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Tag: Particle Physics

  • Dive Into the Elusive World of Particles With the Global Physics Photowalk Finalists

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    Here’s something you rarely see so up close. The photograph above shows one of 18 optical modules inside KM3NeT, a massive detector for neutrinos, which are nearly massless, neutrally charged particles that permeate every corner of the universe. The bubble-like demeanor of the module is reminiscent of where KM3NeT is located: deep under the Mediterranean Sea.

    The photograph, titled “Underwater Hunting,” was a finalist for the 2025 Global Physics Photowalk. The competition, held every three years, seeks to highlight the “visual testaments that capture the beauty, precision, and nature of humankind’s search to understand the universe,” according to the Interactions Collaboration.

    This year, 16 science laboratories around the world each submitted their top three images from the year. Then, a judging panel of physics experts and photographers chose three winners. The public also voted for their top three photographs during a brief selection period.

    “The photographs move between abstraction and lived experience—finding form, rhythm, and quiet beauty in scientific spaces, while foregrounding the people whose labor and curiosity make this work possible,” said Will Warasila, a freelance photographer for The New York Times who was part of the judging panel.

    You can see the list of winners here, but we’ve selected some of our favorites from the entire gallery of 48 finalists, which you can also find here. The Photowalk is also currently on display at the annual meeting of the American Association for the Advancement of Science.

    Research at COLD

    © Marco Donghia

    In this photograph, a young researcher sits alone at the Cryogenic Laboratory for Detectors (COLD) at INFN National Laboratories of Frascati, Italy. In the foreground is the facility’s cryostat, which reaches −459.67 degrees Fahrenheit (-273.14 degrees Celsius) in temperature—nearly absolute zero—so that physicists can probe some of the most enigmatic signals in the universe.

    This entry won first place in the judge’s choice category. Tanea Rauscher, a member of the panel and creative lead at the European Molecular Biology Laboratory, praised the image’s “clear visual storytelling and masterful use of light … [which] creates a quiet, almost cinematic atmosphere that captures both the intensity and the solitude of scientific work.”

    The tunnel

    Le Tunnel
    © Yannig Van De Wouwer / GANIL / CNRS

    In contrast to the judges, the public’s choice for first place went to this bright photograph of a corridor at the Large Heavy Ion National Accelerator in Caen, France. According to Interactions, this particular section of the facility is much brighter than in other areas. The colors of the numerous cables and pipes pop against the backdrop of the metallic room, illuminated by star-shaped lights.

    UNDER 33.5m

    J Parc 1
    © Hisahiro Suganuma

    Advanced facilities in particle physics are huge. That’s because getting enough power to accelerate particles for experiments requires a ton of space, both for the particle flinging itself and the facilities to analyze data, maintain gadgets, etc.

    This often means physicists go underground. For Japan’s Proton Accelerator Research Complex, this added up to roughly 110 feet (33.5 meters). Fully capturing the vast scope of this hole took multiple composites, according to photographer Hisahiro Suganuma.

    Ab Profundis, Scientia,

    Here
    © Adam Tomjack

    As you can imagine, building a particle physics facility is truly a labor of love, tears, and grime. But mostly grime. In this photo, a person shines a headlamp on the wall of the Sanford Underground Research Facility (SURF) in South Dakota, which recently got an expansion. Now, the facility lies up to 4,850 feet (1,479 meters) underground, which SURF says will “house future generations of science.”

    Eye of a Neutrino Telescope

    2 Cppm Eye Of A Neutrino Telescope Hugo Pardinilla
    © Hugo Pardinilla / CPPM / CNRS

    Let’s shift gears again and admire this close-up image of a photomultiplier, also from KM3NeT. Each optical module in KM3NeT holds 31 of these photomultipliers. Together, the entire system forms a gigantic line of neutrino detectors that instruments several million cubic meters of water on the seafloor. This image won third place in the judge’s choice category.

    Where’s Waldo?

    2 Ccin2p3 Mais Où Est Charlie Candicetordjmann
    © Candice Tordjmann / CC-IN2P3 / CNRS

    This photograph shows the dizzying array of wires and components making up a fully operating data center at the French National Centre for Scientific Research. We non-physicists get the privilege of seeing physics discoveries in the form of a neatly organized, peer-reviewed papers, but that underscores the sheer load of data collection that goes into these endeavors.

    Vacuum

    Sous Vide
    © Yannig Van De Wouwer / GANIL / CNRS

    Speaking of enormous volumes of data, an essential part of conducting research with accelerators is identifying patterns. This photograph, awarded second place in the public’s choice category, found some interesting patterns in the casing of a vacuum pipe at the Large Heavy Ion National Accelerator in France.

    FYI, the French title for the photograph is “Sous-vide,” literally French for “under vacuum,” but the phrase might remind English speakers of the meat-cooking technique. I wasn’t sure of the parallels at first, but it sure is funny to think of accelerators as machines that slowly cook particles at precisely regulated temperatures (which they kind of are, I guess).

    AGATA–PRISMA Setup for nuclear physics experiments

    Lnl Agata Prisma
    © Matteo Monzali

    Last but not least, this photograph captured the hearts of both the judging panel and the public, winning second and third place, respectively. Shown here is a photon detector coupled with a magnetic spectrometer at INFN National Laboratories of Legnaro, Italy. These instruments support low- and medium-energy experiments in nuclear physics, which investigates how heavy particles break apart.

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    Gayoung Lee

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  • Advisory panel issues field-defining recommendations for investments in particle physics research

    Advisory panel issues field-defining recommendations for investments in particle physics research

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    Newswise — Yesterday marked the release of a highly anticipated report from the Particle Physics Project Prioritization Panel (P5), unveiling an exciting new roadmap for unlocking the secrets of the cosmos through particle physics.

    The report was released by the High Energy Physics Advisory Panel to the High Energy Physics program of the Office of Science of the U.S. Department of Energy (DOE) and the National Science Foundation’s Division of Physics. It outlines particle physicists’ recommendations for research priorities in a field whose projects — such as building new accelerator facilities — can take years or decades, contributions from thousands of scientists and billions of dollars

    The 2023 P5 report represents the major activity in the field of particle physics that delivers recommendations to U.S. funding agencies. This year’s report builds on the output of the 2021 Snowmass planning exercise — a process organized by the American Physical Society’s (APS) Division of Particles and Fields that convened particle physicists and cosmologists from around the world to outline research priorities. This membership division constitutes the only independent body in the U.S. that represents particle physics as a whole.

    “With our state-of-the-art facilities and community of dedicated scientists, Argonne’s contributions are shaping the global trajectory of high-energy physics.” — Rik Yoshida, Argonne High Energy Physics Division Director

    “With our state-of-the-art facilities and community of dedicated scientists, Argonne’s contributions are shaping the global trajectory of high-energy physics.” — Rik Yoshida, Argonne High Energy Physics Division Director

    “The P5 report will lay the foundation for a very bright future in the field,” said R. Sekhar Chivukula, 2023 chair of the APS Division of Particles and Fields and a distinguished professor of physics at the University of California, San Diego. ​“There are extraordinarily important scientific questions remaining in particle physics, which the U.S. particle physics community has both the capability and opportunity to help address, within our own facilities and as a member of the global high energy physics community.”

    The report includes a range of budget-conscious recommendations for federal investments in research programs, the U.S. technical workforce and the technology and infrastructure needed to realize the next generation of transformative discoveries related to fundamental physics and the origin of the universe. For example, the report recommends continued support for the Deep Underground Neutrino Experiment (DUNE), based out of DOE’s Fermilab in Illinois, for CMB-S4, a network of ground-based telescopes designed to observe the cosmic microwave background (CMB), and for the planned expansion of the South Pole’s neutrino observatory, an international collaboration known as IceCube-Gen2, in a facility operated by the University of Wisconsin–Madison.

    Researchers at DOE’s Argonne National Laboratory stand at the forefront of high energy physics and are poised to contribute significantly to the advancement of the field over the next decade. They are exploring the fundamental nature of the universe and pioneering innovative technologies with far-reaching implications. In particular, Argonne’s High Energy Physics (HEP) division leverages the laboratory’s suite of multidisciplinary facilities and equipment — including world-class scientific computing capabilities — to further scientific discovery and advance accelerator technology. For example, Argonne’s contributions to key high energy physics collaborations include the design and fabrication of components for DUNE, the development of cutting-edge detectors for CMB-S4 and more.

    “With our state-of-the-art facilities and community of dedicated scientists, Argonne’s contributions are helping to shape the global trajectory of high-energy physics,” said Rik Yoshida, director of Argonne’s HEP division. ​“This report reflects the collective wisdom of the high energy physics community, and we look forward to leveraging our expertise and capabilities here at Argonne to help uncover the mysteries of the universe, drive innovation, inspire future generations of scientists and bolster our nation’s vital role in the future of particle physics.”

    “In the P5 exercise, it’s really important that we take this broad look at where the field of particle physics is headed, to deliver a report that amounts to a strategic plan for the U.S. community with a 10-year budgetary timeline and a 20-year context. The panel thought about where the next big discoveries might lie and how we could maximize impact within budget, to support future discoveries and the next generation of researchers and technical workers who will be needed to achieve them,” said Karsten Heeger, P5 panel deputy chair and Eugene Higgins Professor and chair of physics at Yale University.

    New knowledge, and new technologies, set the stage for the most recent Snowmass and P5 convenings. ​“The Higgs boson had just been discovered before the previous P5 process, and now our continued study of the particle has greatly informed what we think may lie beyond the standard model of particle physics,” said Hitoshi Murayama, P5 panel chair and the MacAdams Professor of physics at the University of California, Berkeley. ​“Our thinking about what dark matter might be has also changed, forcing the community to look elsewhere — to the cosmos. And in 2015, the discovery of gravitational waves was reported. Accelerator technology is changing too, which has shifted the discussion to the technology R&D needed to build the next-generation particle collider.”

    The U.S. participates in several major international scientific collaborations in high energy physics and cosmology, including the European Council for Nuclear Research (CERN), which operates the Large Hadron Collider, where the Higgs boson was discovered in 2012. The P5 report recommends that the U.S. support a significant in-kind contribution to a new international facility, the ​“Higgs factory,” to further our understanding of the Higgs boson.

    It also recommends that the U.S. study the possibility of hosting the next most-advanced particle collider facility to reinforce the country’s leading role in international high energy physics for decades to come.

    Activities of the P5 are supported in part by the APS’s Division of Particles and Fields.

    The American Physical Society is a nonprofit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy, and international activities. APS represents more than 50,000 members, including physicists in academia, national laboratories, and industry in the United States and throughout the world.

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    Argonne National Laboratory

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  • New Material Enables an Ultrafast Electron Diffraction Probe for Quantum Materials

    New Material Enables an Ultrafast Electron Diffraction Probe for Quantum Materials

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    Newswise — The Science

    Quantum materials have a host of exotic electronic, magnetic, and optical properties that make them prime candidates for use in future computing and energy technologies. Their properties arise from a complex interaction of their electrons and atomic nuclei. Researchers can observe these interactions as they happen using short pulses of X-rays or electron beams. These pulses last less than a trillionth of a second. Using new materials that emits a narrow electron probe, researchers have developed an ultrafast electron beam technique to probe small, thin pieces of quantum materials with very high resolution.

    The Impact

    Scientists so far cannot create many newly emerging quantum materials as large crystals. Instead, these materials form crystals only one-tenth as wide as a human hair. This poses a challenge for researchers probing these materials using ultrafast electron beam accelerators, as electron beam quality often limits how small an area these beams can focus on. In this study, researchers used a specialized source of electrons to produce a substantial improvement in electron beam quality. This enables crisp images of samples only a few microns wide and of processes that take place in less than a trillionth of a second. This work could lead to a clearer image and understanding of how quantum materials function at atomic space and time scales.

    Summary

    These accelerators typically generate ultrafast electron pulses via a process called photoemission, wherein laser light knocks electrons out of a material, usually a simple metal like copper. If the laser pulse is short in duration, the emitted electron beam will also be short. One challenge with typical photoemission sources is that the electrons emitted do not all travel in the same direction. This spread in emission angle can ultimately limit researchers’ ability to focus the electron beam on a small spot.

    In this work, researchers developed a photoemission-based electron accelerator with an advanced, in-house grown photoemission material that produces many electrons with a much smaller spread in emission angle. Using this source in conjunction with precise electron focusing optics, the researchers performed proof-of-principle ultrafast electron diffraction experiments which showed the ability to resolve subtle atomic details in samples as small as just a few microns in size.

    Funding

    This research was supported by the Department of Energy Office of Science, Basic Energy Sciences and by the National Science Foundation.


    Journal Link: Structural Dynamics, Mar-2022

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    Department of Energy, Office of Science

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  • Researchers Test Quantum Theory with Precision-Engineered Thin Films

    Researchers Test Quantum Theory with Precision-Engineered Thin Films

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    The Science

    Comparing experimental results and theoretical calculations can be difficult for quantum materials. These are materials that have special properties, such as superconductivity, that can only be understood using the rules of quantum mechanics. One way that scientists compare experiments and computations is to use sample materials that isolate and emphasize an atomic line with one dimensional (1D) properties. In this study, scientists grew thin films of layered copper-oxygen (cuprate) materials to isolate 1D copper chains. This allowed them to test theories of how electrons interact in quantum materials. They grew the films under conditions that allowed them to carefully modify the films’ chemistry and electronic structure. They then measured the electronic structure. The research was possible in part because of a specialized synchrotron X-ray beam line designed and built for this purpose.

    The Impact

    Describing how the properties of quantum materials interact and testing related theories are mathematically very complex and time consuming. This work enabled a direct comparison of computational results against experimental measurements. The study indicates that standard theory is not sufficient and requires a new term to fit the experimental data. The work will help scientists refine theories that are essential to describing and engineering new quantum materials and effects. This could eventually lead to new quantum electronic devices.

    Summary

    It is currently impossible to computationally solve the electronic structure of multi-dimensional quantum materials. 1D theory is computationally possible but difficult to test because most materials have 3D structures. The structure of inherently layered 2D cuprate materials can be rearranged, when synthesized in the ultra-thin limit, resulting in 1D copper-oxygen chains that run parallel to the material surface. However, to fully test theories of electron interactions and transport, researchers also need well characterized “doping” defects in the cuprate oxygen stoichiometry.

    In this research, scientists figured out a synthesis method, using ozone during molecular beam epitaxial growth, to add extra oxygen atoms that grab electrons from the copper atoms and create holes in the electronic structure. This was done at a thin film deposition station connected to a synchrotron X-ray beamline that was designed with a sensitive X-ray photoemission spectroscopy capability that can map out the resulting electronic structure. By comparing experimental results with theory, the researchers showed that the standard theory of electron interactions and transport could not predict the 1D doping effects without a modification used to show an unusually strong attraction between certain electrons at longer separations. This attraction is mediated by atomic vibrations. Understanding the coupling between chemistry, defects, vibrations, and the spin direction of electrons are a necessary part of engineering quantum materials for future devices. This work provides a needed direct connection between theory and experiment at the level of correlated electron theory.

     

    Funding

    This work was supported by the Department of Energy (DOE) Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. Film growth and X-ray ARPES experiments were performed at Beamline 5-2 of the Stanford Synchrotron Radiation Light Source, a DOE Office of Science user facility at SLAC National Accelerator Laboratory. Computational resources were provided by the National Energy Research Scientific Computing Center, a DOE Office of Science user facility.

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    Department of Energy, Office of Science

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  • In Preparation for DUNE, Scientists Examine Modern Nuclear Theory for Neutrino Oscillation Physics

    In Preparation for DUNE, Scientists Examine Modern Nuclear Theory for Neutrino Oscillation Physics

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    The Science

    Newswise — The U.S. particle physics community is preparing for a major research program with the Deep Underground Neutrino Experiment (DUNE). DUNE will study neutrino oscillations. These quantum mechanical oscillations are only possible because neutrinos have mass, albeit it very small masses. Research at DUNE will address key questions about neutrinos, such as whether they and their antineutrino counterparts behave differently. Answering these questions could help explain why the universe is composed of matter and not antimatter. These studies require a detailed understanding of how neutrinos interact with atomic nuclei and the nucleons (protons and neutrons) that make up nuclei. By providing new data, DUNE will help scientists advance beyond the current understanding of neutrino-nucleon interactions, which relies upon data from experiments in the 1970s and ‘80s.

    The Impact

    Scientists use the nuclear theory method called Lattice Quantum Chromodynamics (LQCD) to predict neutrino-nucleon interactions. The LQCD results predict a stronger neutrino-nucleon interaction than predictions determined from older, less precise, experimental data. This research demonstrated important implications of how scientists interpret neutrino oscillation signals from LQCD. It also identified the next results to tackle with LQCD. These findings, combined with modern many-body nuclear theory methods, will reduce the potential biases due to incorrect modeling. The findings will also improve scientists’ predictions of these interactions for DUNE and other neutrino experiments.

    Summary

    A recent project by researchers at the University of California, Berkeley and Lawrence Berkeley National Laboratory demonstrated the importance of incorporating state-of-the-art theoretical predictions of the “nucleon axial form factor” into simulations of neutrino-nucleus reactions (a form factor is a measure of the “squishiness” of a particle — the smaller the value, the squishier). Scientists need these form factors to determine oscillation properties of the elusive neutrinos that will be explored by DUNE and other leading neutrino oscillation experiments. The most advanced LQCD predictions conflict with the older phenomenological models of the axial form-factor, leading to a 30% larger neutrino-nucleon cross-section. This has important implications for the interpretation of the oscillation experiments. These LQCD calculations are made possible by the Department of Energy’s Leadership Class Computing Facilities, which house the fastest supercomputers in the world.

    In the exascale computing era, scientists will further refine the LQCD results and tackle additional, more complicated processes. The results will be combined with modern many-body nuclear theory methods to provide more robust predictions of the neutrino-nucleus reactions. These predictions are essential ingredients for interpreting the next-generation neutrino oscillation experiments, such as DUNE, and inferring properties of neutrinos.

     

    Funding

    This work is supported in part by the Department of Energy Office of Science, High Energy Physics and Nuclear Physics programs.


    Journal Link: Annual Reviews in Nuclear and Particle Science, Sep-2022

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    Department of Energy, Office of Science

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  • Four Brookhaven Scientists Receive Early Career Research Awards

    Four Brookhaven Scientists Receive Early Career Research Awards

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    Newswise — UPTON, NY—Four scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have been selected by DOE’s Office of Science to receive significant funding through its Early Career Research Program. The program, which began in 2010, bolsters the nation’s scientific workforce by supporting exceptional researchers at the outset of their careers, when many scientists do their most formative work.

    The awards are a part of the DOE’s long-standing efforts to develop the next generation of STEM leaders to solidify America’s role as the driver of science and innovation around the world.

    “Supporting America’s scientists and researchers early in their careers will ensure the United States remains at the forefront of scientific discovery,” said U.S. Secretary of Energy Jennifer M. Granholm. “The funding announced today gives the recipients the resources to find the answers to some of the most complex questions as they establish themselves as experts in their fields.”

    DOE is recognizing a total of 93 awardees representing 47 universities and 12 DOE National Laboratories in 27 states. Awardees were selected based on peer review by outside scientific experts.

    The projects announced today are selections for negotiation of a financial award, and cover projects lasting up to five years in duration. The final details for each are subject to final grant and contract negotiations between DOE and the awardees. The Early Career Research Program is funded by DOE’s Office of Science.

    Information about the 93 awardees and their research projects is available on the Early Career Research Program webpage.

    This year’s Brookhaven Lab awardees are:

    Elizabeth (Liza) Brost, “Shining Light on the Higgs Self-Interaction”

    Elizabeth Brost, an associate scientist in Brookhaven Lab’s Physics Department, will receive funding through the DOE’s Office of High Energy Physics to study properties of the Higgs boson, including its self-interaction.

    Discovered in 2012 at the Large Hadron Collider (LHC) at CERN in Switzerland, the Higgs boson is the fundamental particle associated with the Higgs field, which imparts mass to other fundamental particles. The Standard Model of particle physics, scientists’ best understanding of the particles and forces that make up our world, predicts that the Higgs field can interact with itself. This self-interaction should contribute to the production of pairs of Higgs bosons at the LHC. Brost’s studies of Higgs pair production will provide a path towards measuring the Higgs self-interaction—and ultimately a deeper understanding of the Higgs boson’s role in the Standard Model.

    One major challenge is that pair production of Higgs bosons is extraordinarily rare in proton-proton collisions at the LHC—more than 1000 times rarer than collisions producing single Higgs bosons! In this project, Brost will lead the development of novel techniques to select fruitful collision data in real time using machine learning algorithms. Using data from the LHC’s ATLAS detector, she and her collaborators will search for the direct and indirect effects of “new physics” beyond the Standard Model on Higgs pair production. These measurements may confirm that the Higgs behaves as expected in the Standard Model. Or they may point to the influences of new physics, which must then be incorporated into explanations of the Higgs mechanism and other areas of physics.

    “I am honored to receive this Early Career Award, which will enable me to pursue some of the most interesting open questions in high energy physics,” Brost said. “The analysis and data-collection techniques developed through this project will advance our understanding of the Higgs boson at unprecedented scales, not only at the LHC but also at proposed future colliders.”

    Brost earned her undergraduate degree in physics and French from Grinnell College in 2010 and her Ph.D. in physics from the University of Oregon in 2016. After serving as a postdoctoral research associate at Northern Illinois University from 2016 to 2019, she joined Brookhaven National Laboratory as an assistant physicist. She was promoted to associate physicist in 2021. Stationed at Europe’s CERN laboratory, home to the LHC, Brost has led groups of hundreds of ATLAS physicists on a range of analyses and detector upgrades, many associated with “di-Higgs” searches. She also has extensive experience mentoring students and postdocs, who will play important roles in executing the goals of this Early Career Award project.

    Esther Tsai, “Virtual Scientific Companion for Synchrotron Beamlines” 

    Esther Tsai, a scientist in the Electronic Nanomaterials Group of the Center for Functional Nanomaterials (CFN), aims to strengthen the interactions between human scientists and the artificial intelligence/machine learning (AI/ML) tools that can accelerate their research. With funding from the DOE Office of Basic Energy Sciences, she is developing a revolutionary system that will allow scientists to launch experiments and analyze data using a conversational interface.

    She’s particularly interested in alleviating bottlenecks at the National Synchrotron Light Source II (NSLS-II)—a source of extremely intense x-rays used by more than 1,700 researchers from universities, industry, and other national laboratories each year to study the properties of a wide range of materials. Currently, CFN and NSLS-II staff collaborate with these facility “users,” assisting in the setup, scientific planning/discussion, and analysis of data from experiments at several beamlines run in partnership by these two DOE Office of Science user facilities. Their research on complex materials has the potential to improve the performance of electronics, solar cells, batteries, and other applications. But the beamlines are often understaffed and oversubscribed.

    “Beamline scientists have the daunting mission of supporting various aspects of beamline operation and user science through tireless and sleepless efforts,” Tsai said.

    Her goal is to develop a virtual scientific companion, known as VISION, that will synergistically connect researchers with computational tools to speed up the experimentation so everyone can make more discoveries—and possibly get more sleep.

    The virtual assistant will leverage modern developments in natural language (NL) processing and language models—the technology underpinning the revolutionary capabilities of chatbots and AI assistants. Tsai will tailor these methods to scientific experiments, allowing researchers to input queries in ordinary language without the need for complex coding. VISION will transcribe NL voice to text, acquire and analyze data, visualize results, and provide advanced learning algorithms and physics modeling to suggest optimal experiment design or hypotheses for further exploration. This powerful, general approach can be extended to a host of scientific instruments to accelerate the pace of discovery across the DOE complex.

    “We’re not taking humans out of the picture; we’re actually making it easier for humans to use their natural form of expression, whether speaking or texting, to leverage the strengths of powerful AI/ML programming. We envision a new era where human NL-based communication will be the only needed interface for scientific experimentation and design,” said Tsai.

    “It is a great honor and responsibility to receive this Early Career Award. I am so very grateful for the support I’ve received from colleagues at Brookhaven and especially my group leader, Kevin Yager,” Tsai said. “I will continue to need their support to introduce this new paradigm of NL-controlled scientific expedition.”

    Tsai earned a bachelor’s degree in electrical engineering in 2009 and a Ph.D. in electrical and computer engineering in 2014, both from Purdue University. Before joining Brookhaven Lab’s CFN as an assistant scientist in 2018, she conducted postdoctoral research and provided user support at the Swiss Light Source at the Paul Scherrer Institute from 2015 to 2018. She was promoted to associate scientist at Brookhaven in 2021, and to scientist in 2023.

    Derong Xu, “Luminosity Maximization with Flat Hadron Beams”

    Derong Xu, an assistant physicist working on the future Electron-Ion Collider (EIC) at Brookhaven Lab, is striving to maximize the collider’s most important figure of merit by maintaining the flatness of a beam of ions travelling at nearly the speed of light.

    The EIC will collide two beams—one containing electrons and the other containing protons or other atomic nuclei. The collisions between individual electrons and other ions will produce data that scientists will use to study the internal structure of protons and nuclei, including the arrangement of those particles’ quarks and gluons. If more particle collisions occur, scientists can produce and analyze more data that contribute to our understanding of how visible matter evolved from the quark-gluon plasma studied over the past two decades at the Relativistic Heavy Ion Collider (RHIC), an Office of Science user facility at Brookhaven.

    Physicists can increase the likelihood of these collisions occurring by reducing beam size—packing the same number of particles into a smaller space. This methodology, known as maximizing “luminosity,” is exactly what Xu will work on for the EIC with funding from DOE’s Office of Nuclear Physics. According to calculations by Xu and his colleagues, flattening the ion beam of the EIC will help attain the maximum luminosity. This approach has never been used in a hadron collider—a machine that collides composite particles made of quarks and gluons.

    Though scientists can generate flat ion beams, maintaining this flatness as trillions of charged particles whirl around a collider is a challenge. There are numerous potential interactions, such as those between beams and the superconducting accelerator magnets, that could compromise the quality of the beam and make it harder to focus it to a small, flat spot size at the collision point. Xu’s work will dissect the interactions that could alter beam flatness and investigate methods to reduce or eliminate these effects to maintain high luminosity.

    “Our efforts to improve the luminosity for the EIC will also benefit other future colliders,” said Xu. “I am excited to contribute to this important research endeavor.”

    “I am deeply honored to receive this award and express my heartfelt gratitude for this exceptional opportunity,” Xu added. “The challenge of using a flat beam in future colliders captivates me, and I am eager to explore this topic further.”

    Xu studied accelerator physics at the University of Science and Technology of China (USTC), receiving a bachelor’s degree in 2011 and a Ph.D. in 2016. Xu was a postdoctoral fellow from 2017 to 2018 and then a research fellow from 2018 to 2019 at the National Synchrotron Radiation Laboratory at USTC. Xu’s work on the EIC began at Michigan State University in 2019 and continued at Brookhaven when he joined the Lab in 2021 as an assistant physicist.

    Joanna M Zajac, “Interactions of QDs’ Fast Light in Rb Vapors for Hybrid Quantum Information Science and Technology” 

    Joanna M Zajac, a quantum scientist in the Instrumentation Division, is tackling one of the biggest challenges in quantum networking—developing a fundamental understanding of fast light-matter interconnects that could one day facilitate long distance quantum networks.

    With funding from the DOE Office of Basic Energy Sciences, she will design and build systems that use quantum dots (QD) to generate identical single photons (the simplest fundamental portions of light) in the wavelengths used for optical telecommunication. Quantum dots are light-emitting semiconductor nanostructures whose emission can be tuned to different wavelengths. They could potentially generate photons suitable to work at telecommunication and atomic wavelengths. That would help to reduce the high losses currently experienced when quantum information travels through the telecommunication optical fibers network. 

    The goal is then to couple QD single photons with alkali vapors, such as rubidium (Rb), which can reliably store quantum information. These light-matter interconnects may one day operate as a basis for quantum repeaters that receive and then re-emit quantum information making up nodes of quantum network connected by optical links over long distances. This research could be applied to a range of areas in quantum information science and technology such as quantum computing, quantum communications, and quantum sensing.

    “Fast light-matter interconnects made of alkali atomic ensembles and photons from quantum dots (QDs) create a heterogenous system that combines the advantages of its homogenous components’, Zajac said. “Within this project we are going to develop fundamental understanding of interactions therein allowing us to develop components of long-distance quantum networks in the future. This DOE award gives me a fantastic opportunity to explore this important topic among the vibrant scientific community in Brookhaven Lab’s Instrumentation Division and beyond.”

    Zajac pursued her education in the United Kingdom, earning her master’s degree in physics from Southampton University in 2008 and her Ph.D. in physics from Cardiff University in 2013. She was a postdoctoral research associate at Heriot-Watt University from 2013 to 2016 and a research fellow at St. Andrews University in 2016. Before joining Brookhaven Lab’s Instrumentation Division as a quantum scientist in 2021, she was a senior researcher at Oxford University (2020-21), United Kingdom.

    Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.

    Follow @BrookhavenLab on social media. Find us on Instagram, LinkedIn, Twitter, and Facebook.

    Denise Yazak and Danielle Roedel contributed to the writing of this news release.

     

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    Brookhaven National Laboratory

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  • Nuclear Charge Distribution Measurements May Solve Outstanding Puzzle In Particle Physics

    Nuclear Charge Distribution Measurements May Solve Outstanding Puzzle In Particle Physics

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    The Science

    What scientists call the “nuclear weak distribution” describes the distribution of “active” protons in a nucleus. These are protons that are eligible to transition into neutrons through what scientists call the “weak interaction.” Researchers recently reviewed the existing standard procedure to determine this distribution. In the study, they abandoned previous treatments using nuclear shell models. Instead, they related the weak distribution to the distribution of electric charges in a nucleus. Scientists can measure this distribution by scattering electrons off nuclear targets or by studying energy levels through atomic spectroscopy.

    The Impact

    The new data-driven analysis found significant differences with the results of previous model-based determinations of the nuclear weak distribution. This result advances the search for new physics based on nuclear beta decay experiments. It does so by providing a partial explanation for a discrepancy between predictions from particle physics theory and experimental measurement of a fundamental quantity called “Vud.” This term describes how quarks transition from one type to another inside a proton or neutron, thus changing the particles.

    Summary

    The extracted value of “Vud” from nuclear beta decays seems to be substantially smaller than what is required by the Standard Model of Particle Physics, the commonly-acknowledged best theory for elementary particle physics. This observed anomaly stimulates vibrant discussions of possibilities of new physics discoveries. To study its origin, researchers at the Facility for Rare Isotope Beams (FRIB) at Michigan State University investigated the so-called “nuclear weak distribution.” They found that the current understanding of this distribution is based on rather simple models that assume non-interacting nucleons inside a nucleus. Furthermore, they showed that this distribution may be determined independently of models using measurements of nuclear charge distributions, which can be done either through electron-nucleus scattering experiments or through atomic spectroscopy.

    Upon analyzing existing data, the researchers found that the value of Vud moved closer to the Standard Model prediction. Future measurements of nuclear charge distributions, for example at FRIB, may provide further insights towards the resolution of the Vud anomaly.

     

    Funding

    This work is supported in part by the Department of Energy Office of Science, Office of Nuclear Physics.


    Journal Link: Physical Review Letters, Apr-2023

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    Department of Energy, Office of Science

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  • Noise-free comms via structured light, say researchers

    Noise-free comms via structured light, say researchers

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    Newswise — The patterns of light hold tremendous promise for a large encoding alphabet in optical communications, but progress is hindered by their susceptibility to distortion, such as in atmospheric turbulence or in bent optical fibre.  Now researchers at the University of the Witwatersrand (Wits) have outlined a new optical communication protocol that exploits spatial patterns of light for multi-dimensional encoding in a manner that does not require the patterns to be recognised, thus overcoming the prior limitation of modal distortion in noisy channels.  The result is a new encoding state-of-the-art of over 50 vectorial patterns of light sent virtually noise-free across a turbulent atmosphere, opening a new approach to high-bit-rate optical communication.  

    Published this week in Laser & Photonics Reviews, the Wits team from the Structured Light Laboratory in the Wits School of Physics used a new invariant property of vectorial light to encode information.  This quantity, which the team call “vectorness”, scales from 0 to 1 and remains unchanged when passing through a noisy channel.  Unlike traditional amplitude modulation which is 0 or 1 (only a two-letter alphabet), the team used the invariance to partition the 0 to 1 vectorness range into more than 50 parts (0, 0.02, 0.04 and so on up to 1) for a 50-letter alphabet.  Because the channel over which the information is sent does not distort the vectorness, both sender and received will always agree on the value, hence noise-free information transfer.  

    The critical hurdle that the team overcame is to use patterns of light in a manner that does not require them to be “recognised”, so that the natural distortion of noisy channels can be ignored.  Instead, the invariant quantity just “adds up” light in specialised measurements, revealing a quantity that doesn’t see the distortion at all.

    “This is a very exciting advance because we can finally exploit the many patterns of light as an encoding alphabet without worrying about how noisy the channel is,” says Professor Andrew Forbes, from the Wits School of Physics. “In fact, the only limit to how big the alphabet can be is how good the detectors are and not at all influenced by the noise of the channel.”

    Lead author and PhD candidate Keshaan Singh adds: “To create and detect the vectorness modulation requires nothing more than conventional communications technology, allowing our modal (pattern) based protocol to be deployed immediately in real-world settings.”

    The team have already started demonstrations in optical fibre and in fast links across free-space, and believe that the approach can work in other noisy channels, including underwater.

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    University of the Witwatersrand

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  • Rouven Essig: Then and Now / 2012 Early Career Award Winner

    Rouven Essig: Then and Now / 2012 Early Career Award Winner

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    WHAT DID THE 2012 EARLY CAREER AWARD ALLOW YOU TO DO?

    Extensive evidence suggests that a staggering 85% of the matter in our universe is dark matter. However, its identity remains unknown. Even its most basic properties – such as how much it weighs and how it interacts with known matter – remain unknown.

    As a theoretical particle physicist, I conceive of new ideas for what constitutes dark matter. I also develop new experimental concepts for how to detect dark matter particles and any unknown forces that allow dark matter to interact with ordinary matter. My theoretical research impacts how other scientists do research at the cosmic, intensity, and energy frontiers.

    For the cosmic frontier, I have helped pioneer novel detection concepts to search for dark matter below the mass of protons. This has led to new exciting experiments, such as SENSEI, as well as new DOE research and development efforts, such as OSCURA. These projects have unprecedented sensitivity to a multitude of dark matter candidates that were previously unexplored.

    For the intensity frontier, I have conceived of new experiments. In these experiments, intense beams of electrons hit a target and potentially create particles that mediate new forces beyond the known electromagnetic, strong, and weak forces. This has led to new fixed-target experiments at DOE’s Jefferson Lab, including APEX and HPS.  

    For the energy frontier, I have shown how the Higgs bosons produced in high-energy proton-proton collisions at the Large Hadron Collider can shed light on dark matter and new forces. This has led to new searches for non-standard decays of the Higgs boson, in which it disintegrates in ways not expected by our standard theory.

    Most importantly, the DOE Early Career Award allowed me to train several graduate students and a postdoctoral researcher in particle physics. It enabled me to establish a strong research program and research group early on in my career, providing a strong foundation from which I continue to benefit.

    ABOUT:

    Rouven Essig is a professor in the C.N. Yang Institute for Theoretical Physics at Stony Brook University.

    SUPPORTING THE DOE SC MISSION:

    The Early Career Research Program provides financial support that is foundational to early career investigators, enabling them to define and direct independent research in areas important to DOE missions. The development of outstanding scientists and research leaders is of paramount importance to the Department of Energy Office of Science. By investing in the next generation of researchers, the Office of Science champions lifelong careers in discovery science.

    For more information, please go to the Early Career Research Program.

    THE 2012 PROJECT ABSTRACT:

    Title: Particle Physics at the Cosmic, Intensity, and Energy Frontiers

    Abstract

    Major efforts at the intensity, cosmic, and energy frontiers of particle physics are rapidly furthering our understanding of the fundamental constituents of Nature and their interactions. The overall objectives of this research project are (1) to interpret and develop the theoretical implications of the data collected at these frontiers and (2) to provide the theoretical motivation, basis, and ideas for new experiments and for new analyses of experimental data.

    Within the Intensity Frontier, an experimental search for a new force mediated by a GeV‐scale gauge boson will be carried out with the A’ Experiment (APEX) and the Heavy Photon Search (HPS), both at Jefferson Laboratory. Within the Cosmic Frontier, contributions are planned to the search for dark matter particles with the Fermi Gamma‐ray Space Telescope and other instruments. A detailed exploration will also be performed of new direct detection strategies for dark matter particles with sub‐GeV masses to facilitate the development of new experiments. In addition, the theoretical implications of existing and future dark‐ matter‐related anomalies will be examined. Within the Energy Frontier, the implications of the data from the Large Hadron Collider will be investigated. Novel search strategies will be developed to aid the search for new phenomena not described by the Standard Model of particle physics. By combining insights from all three particle physics frontiers, this research aims to increase our understanding of fundamental particle physics.

    RESOURCES:

    D Curtin, R Essig, S Gori, P Jaiswal, A Katz, T Liu, Z Liu, D McKeen, J Shelton, M Strassler, Z Surujon, B Tweedie, and YM Zhong, “Exotic decays of the 125 GeV Higgs boson.” Phys Rev D 90, 75004 (2014). [DOI: /10.1103/PhysRevD.90.075004]

    R Essig, M Fernández-Serra, J Mardon, A Soto, T Volansky & TT Yu, “Direct detection of sub-GeV dark matter with semiconductor targets.” Journal of High Energy Physics 2016, 46 (2016). [DOI: /10.1007/JHEP05(2016)046]

    R Essig, T Volansky, and TT Yu, “New constraints and prospects for sub-GeV dark matter scattering off electrons in xenon.” Phys Rev D 96, 043017 (2017). [DOI: 10.1103/PhysRevD.96.043017] 

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    Department of Energy, Office of Science

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  • Princeton University awards plasma physics graduate student Suying Jin a highly selective honorific fellowship

    Princeton University awards plasma physics graduate student Suying Jin a highly selective honorific fellowship

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    Jin expressed deep appreciation on receiving the fellowship. “I feel truly honored, and I’m fortunate to be at an institution that lifts up its students in this way,” she said. “I am also deeply grateful for all the support, academic and otherwise, that has made this possible.”

    The Program in Plasma Physics is based at the Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) and is a graduate program within the Department of Astrophysical Sciences at Princeton University. Graduates of the program have shaped the field of plasma physics in recent decades, working in academia, national laboratories, industry and beyond.

    Spontaneously arising order

    Jin’s dissertation is investigating the challenging question of how plasmas self-organize in the presence of magnetic fields. “You see it happening all the time, everywhere in the universe, where you have order spontaneously arising from turbulence or chaos,” she said. “I like to go after things that defy intuition and much about the mechanism by which this self-organization occurs remains mysterious.  

    When her advisor, principal research physicist Ilya Dodin, offered Jin several thesis topics to choose from, “Suying fearlessly chose the most challenging project over low-hanging fruits,” Dodin said. “She felt that although immediate rewards were not to be expected, the results of that project would be more important in the long run. I have much respect for that attitude,” he said. “Suying is an outstanding researcher and a classic role model who strongly deserves a Princeton honorific fellowship.”

    Jin traces her passionate interest in plasma science to her preparation for a final exam at the University of California, Los Angeles  (UCLA), where she graduated in physics with honors in 2018. “I was working my way through an electrodynamics textbook, and I came across this problem that introduced me to the whole idea of plasma,” she said. “It was my first time thinking about what would happen if you had a bunch of charged particles together and it seemed like anything would be possible in a medium like that.”

    Basic Science

    While her thesis topic “is basic science and not fusion focused, ultimately, I think the fusion effort will benefit greatly from just fundamental plasma research,” she said. “There’s a lot we still need to understand about plasmas, period.”

    Her dedication to learning extends to teaching, which she has pursued as a teaching assistant at the graduate and undergraduate levels. She’s taught in Dodin’s graduate class in plasma waves, where “she was very proactive and did a great job,” he recalls. She also helped teach an undergraduate course in fusion and fission that has expanded her interest in real-world problems.

    Her research has led to frequent peer-reviewed publications, including five papers as a first author and two as a co-author. In addition, she shares a patent disclosure with two PPPL physicists.

    Outside the classroom, Jin has been an active participant in plasma programs. She was a cofounder of Princeton Women in Plasma Physics (PWiPP), whose mission includes promoting “a supportive community for women and gender minorities in plasma physics at Princeton.”  She has lectured at plasma physics workshops and been a panelist and discussion leader at a local conference for undergraduate women in physics.

    Tae Kwon Do

    When not deeply engaged in plasma physics, Jin pursues long-time hobbies including the Korean martial art Tae Kwon Do, in which she holds a black belt and has practiced for 15 years. She also enjoys cooking and playing the piano.

    Looking ahead, Jin says she would prefer a teaching job to a purely research position and sees herself “continuing down the path of academia. “I’ve had such fantastic mentors from day one when I entered this field, and I would really like to work with students to pass that mentorship along.”

    The Program in Plasma Physics has graduated more than 300 students since it began in 1959.
    In an environment that, over the past few decades, has seen enormous changes in the fields of plasma physics and controlled fusion, the program has consistently focused on fundamentals in physics and mathematics and on intense exposure to contemporary experimental and theoretical research in plasma physics. Learn more.

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    Princeton Plasma Physics Laboratory

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  • Quantum-Enhanced Microscope Doubles Resolution

    Quantum-Enhanced Microscope Doubles Resolution

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    Newswise — Using a “spooky” phenomenon of quantum physics, Caltech researchers have discovered a way to double the resolution of light microscopes.

    In a paper appearing in the journal Nature Communications, a team led by Lihong Wang, Bren Professor of Medical Engineering and Electrical Engineering, shows the achievement of a leap forward in microscopy through what is known as quantum entanglement. Quantum entanglement is a phenomenon in which two particles are linked such that the state of one particle is tied to the state of the other particle regardless of whether the particles are anywhere near each other. Albert Einstein famously referred to quantum entanglement as “spooky action at a distance” because it could not be explained by his relativity theory.

    According to quantum theory, any type of particle can be entangled. In the case of Wang’s new microscopy technique, dubbed quantum microscopy by coincidence (QMC), the entangled particles are photons. Collectively, two entangled photons are known as a biphoton, and, importantly for Wang’s microscopy, they behave in some ways as a single particle that has double the momentum of a single photon.

    Since quantum mechanics says that all particles are also waves, and that the wavelength of a wave is inversely related to the momentum of the particle, particles with larger momenta have smaller wavelengths. So, because a biphoton has double the momentum of a photon, its wavelength is half that of the individual photons.

    This is key to how QMC works. A microscope can only image the features of an object whose minimum size is half the wavelength of light used by the microscope. Reducing the wavelength of that light means the microscope can see even smaller things, which results in increased resolution.

    Quantum entanglement is not the only way to reduce the wavelength of light being used in a microscope. Green light has a shorter wavelength than red light, for example, and purple light has a shorter wavelength than green light. But due to another quirk of quantum physics, light with shorter wavelengths carries more energy. So, once you get down to light with a wavelength small enough to image tiny things, the light carries so much energy that it will damage the items being imaged, especially living things such as cells. This is why ultraviolet (UV) light, which has a very short wavelength, gives you a sunburn.

    QMC gets around this limit by using biphotons that carry the lower energy of longer-wavelength photons while having the shorter wavelength of higher-energy photons.

    “Cells don’t like UV light,” Wang says. “But if we can use 400-nanometer light to image the cell and achieve the effect of 200-nm light, which is UV, the cells will be happy, and we’re getting the resolution of UV.”

    To achieve that, Wang’s team built an optical apparatus that shines laser light into a special kind of crystal that converts some of the photons passing through it into biphotons. Even using this special crystal, the conversion is very rare and occurs in about one in a million photons. Using a series of mirrors, lenses, and prisms, each biphoton—which actually consists of two discrete photons—is split up and shuttled along two paths, so that one of the paired photons passes through the object being imaged and the other does not. The photon passing through the object is called the signal photon, and the one that does not is called the idler photon. These photons then continue along through more optics until they reach a detector connected to a computer that builds an image of the cell based on the information carried by the signal photon. Amazingly, the paired photons remain entangled as a biphoton behaving at half the wavelength despite the presence of the object and their separate pathways.

    Wang’s lab was not the first to work on this kind of biphoton imaging, but it was the first to create a viable system using the concept. “We developed what we believe a rigorous theory as well as a faster and more accurate entanglement-measurement method.  We reached microscopic resolution and imaged cells.”

    While there is no theoretical limit to the number of photons that can be entangled with each other, each additional photon would further increase the momentum of the resulting multiphoton while further decreasing its wavelength.

    Wang says future research could enable entanglement of even more photons, although he notes that each extra photon further reduces the probability of a successful entanglement, which, as mentioned above, is already as low as a one-in-a-million chance.

    The paper describing the work, “Quantum Microscopy of Cells at the Heisenberg Limit,” appears in the April 28 issue of Nature Communications. Co-authors are Zhe He and Yide Zhang, both postdoctoral scholar research associates in medical engineering; medical engineering graduate student Xin Tong (MS ’21); and Lei Li (PhD ’19), formerly a medical engineering postdoctoral scholar and now an assistant professor of electrical and computer engineering at Rice University.

    Funding for the research was provided by the Chan Zuckerberg Initiative and the National Institutes of Health.

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    California Institute of Technology

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  • Zeroing in on a Fundamental Property of the Proton’s Internal Dynamics

    Zeroing in on a Fundamental Property of the Proton’s Internal Dynamics

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    The Science

    Inside the proton are elementary particles called quarks. Quarks and protons have an intrinsic angular momentum called spin. Spin can point in different directions. When it is perpendicular to the proton’s momentum, it is called a transverse spin. Just like the proton carries an electric charge, it also has another fundamental charge called the tensor charge. The tensor charge is the net transverse spin of quarks in a proton with transverse spin. The only way to obtain the tensor charge from experimental data is using the theory of quantum chromodynamics (QCD) to extract the “transversity” function. This universal function encodes the difference between the number of quarks with their spin aligned and anti-aligned to the proton’s spin when it is in a transverse direction. Using state-of-the-art data science techniques, researchers recently made the most precise empirical determination of the tensor charge.

    The Impact

    Due to the phenomenon known as “confinement,” quarks are always bound in the proton or other hadrons (particles with multiple quarks). The challenge is to connect the theory of quark interactions (QCD) to experimental measurements of high-energy collisions involving hadrons. In this study, researchers used a complete collection of transverse-spin data from electron-positron, electron-proton, and proton-proton scattering in the first global analysis of its kind. They employed this data to make the most precise known empirical calculation of the tensor charge. Scientists need a precise and accurate determination of the proton’s tensor charge to understand the proton’s internal structure and the dynamics of QCD strong interactions. This information is also very important in searches for new physics.

    Summary

    Researchers from the Coordinated Theoretical Approach to Transverse Momentum Dependent Hadron Structure in QCD Topical Collaboration (TMD Collaboration) , working in conjunction with the Thomas Jefferson National Accelerator Facility (Jefferson Lab) Angular Momentum Collaboration (JAM Collaboration), analyzed data from a wide range of experiments where protons and/or quarks were transversely polarized. This allowed for the most precise empirical determination of the proton’s tensor charge. The tensor charge is not only a fundamental property of the proton but also needed in searches for new physics. The results were then compared to computations of the proton’s tensor charge by lattice QCD, which simulates the proton’s structure on a supercomputer. After about a decade of results showing disagreement between empirical methods and lattice QCD for the proton’s tensor charge, researchers for the first time found agreement between the two.

    The empirical study was performed using QCD theory and state-of-the-art numerical methods. A crucial part of the analysis was the utilization of data from electron-positron, electron-proton, and proton-proton scattering. This opens a new frontier in QCD global analyses to simultaneously include all possible measurements, like those from the future Electron-Ion Collider and Jefferson Lab 12 GeV, to continue to increase the precision and accuracy of extracting the proton’s tensor charge.

     

    Funding

    This work was supported by the Department of Energy Office of Science, Nuclear Physics program under the Coordinated Theoretical Approach to Transverse Momentum Dependent Hadron Structure in QCD (TMD Topical Collaboration). This work was also supported in part by the Department of Energy and the National Science Foundation and the agencies’ Early Career Programs.


    Journal Link: Physical Review D, Aug-2022

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    Department of Energy, Office of Science

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  • Farm waste turned into air-cleaning substance

    Farm waste turned into air-cleaning substance

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    Newswise — Air pollution and its high concentration in cities is one of the problems facing society today, due to its harmful effects on the environment, but also on human health. One of the causes of this pollution is the increase in nitrogen oxide emissions, mainly due to the use of fossil fuels.

    While the emissions of these gases are being reduced, photocatalysis is proving to be a tool for decontaminating air in cities: materials called semiconductors are created which, when coming into contact with the pollutant, under the effect of ultraviolet light, cause it to degrade, thus reducing its concentration in the air.

    Two research groups of the University of Cordoba, belonging to the Chemical Institute for Energy and the Environment (IQUEMA),and the Department of Inorganic Chemistry and Chemical Engineering,have been working to produce these materials. The team,formed by the BioPrEn and Inorganic Chemistry groups, has obtained biodegradable materials to fix nanoparticles with photocatalytic activity (in this case, titanium dioxide), augmentingthe power and, therefore,the decontaminating effect.

    The advances made by this work consist of “first, the creation of a biodegradable medium based on nanocellulose, obtained from agricultural waste; and, second, the development of a surface modification process of these nanoparticles, which results on their greater dispersion and immobilization,and, therefore, enhanced photocatalytic activity”, explains one of the authors of the article, researcher Eduardo Espinosa.

    The progress is twofold: it is possible to create a sustainable material by recovering a form of agricultural waste(thus contributing to the Circular Economy) and the process of fixing photocatalytic nanoparticles to this biodegradable medium is simplified. The benefit is, in fact, exponential, since the result is greater air decontamination due to the porosity and the three-dimensional nature of the material, which means that more photocatalytic particles are exposed to ultraviolet light compared to an opaque material or one in which only one surface is exposed to light.

    What is it like? Where is it used?

    Those who see this material will recognize a light, solid foam, but with very little density, similar to insulation coverings used in construction,or the popular corn “puffs.” To effect decontamination “it can be used as a porous filter through which the gas stream passes, always exposed to ultraviolet light, and the gas comes out decontaminated,” says Espinosa. Thus, gases released by industry, for example, would come out almost clean of nitrogen oxides.

    A further step in this research would be to modify the photocatalytic particle so that it is more sensitive to light from the visible spectrum, without having to resort to ultraviolet sources. In this way the photocatalytic power would be activated by sunlight alone, and this type of technology could be applied to textiles and other types of materials,thereby reducing the concentration of gases only through exposure to the sun.

    References:

    Carrasco, Sergio & Espinosa Víctor, Eduardo & González, Zoilo & Cruz-Yusta, Manuel & Sánchez, Luis & Rodríguez, Alejandro (2023). Simple Route to Prepare Composite Nanocellulose Aerogels: A Case of Photocatalytic De-NO x Materials Application. ACS Sustainable Chemistry &Engineering. https://doi.org/10.1021/acssuschemeng.2c06170

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    University of Cordoba

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  • Signs of Gluon Saturation Emerge from Particle Collisions

    Signs of Gluon Saturation Emerge from Particle Collisions

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    The Science

    Nuclear physicists collide protons with heavier ions (atomic nuclei) to explore the fundamental constituents that make up those ions. By tracking particles that stream out of the collisions, they can zoom in beyond the ions’ protons and neutrons to study those particles’ innermost building blocks—quarks and gluons. Recent results revealed a suppression of certain back-to-back pairs of particles that emerge from interactions of single quarks from the proton with single gluons in the heavier ion. The suppression was greatest in collisions with the heaviest nuclei. The results suggest that gluons in heavy nuclei recombine, as predicted by the theory of the strong force, quantum chromodynamics.

    The Impact

    Previous experiments have shown that when ions are accelerated to high energies, gluons split to multiply to very high numbers. But scientists suspect that gluon multiplication can’t go on forever. Instead, in nuclei moving close to the speed of light, where relativistic motion flattens the nuclei into speeding gluon “pancakes,” overlapping gluons should start to recombine. Seeing evidence of recombination would be a step toward proving that gluons reach a postulated steady state called saturation, where gluon splitting and recombination balance out. The new results match with theoretical models postulating this saturated state.

    Summary

    To search for signs of gluon recombination, scientists with the STAR Collaboration used the STAR detector at the Relativistic Heavy Ion Collider, a Department of Energy Office of Science user facility. They were looking for a telltale signal produced in collisions of protons with a range of ions when a single quark from the proton interacts with an individual gluon in the ion. That signal is a pair of neutral pions striking a forward detector at back-to-back angles. If gluons in the nuclei recombine, scientists would expect to see a suppression in this back-to-back signal because fewer gluons would be available for the quark-gluon interactions. They looked for the signal in collisions of protons with different sized ions.

    Theorists had predicted that gluon recombination would be more prominent the larger the ion. That’s because heavy ions (nuclei) have more quark-and-gluon-containing protons and neutrons. When accelerated to near the speed of light, these ions flatten out, making the abundant gluons overlap and more likely to merge. Bigger nuclei with more gluons, should mean more merging and more suppression in the signal. That’s exactly what the scientists found. The results provide evidence that gluons recombine—and a strong suggestion that gluon splitting and recombination could produce the predicted saturated state.

     

    Funding

    This research was funded by the Department of Energy Office of Science, Nuclear Physics program, the National Science Foundation, and a range of international agencies listed in the published paper.

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    Department of Energy, Office of Science

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  • A surprising way to trap a microparticle

    A surprising way to trap a microparticle

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    • New study finds obstacles can trap rolling microparticles in fluid
    • Through simulations and experiments, physicists attribute the trapping effect to stagnant pockets of fluid, created by hydrodynamics
    • Random motions of the molecules within the fluid then ‘kick’ the microroller into a stagnant pocket, effectively trapping it
    • Size of the obstacle also controls how easy it is to trap a microroller and how long it remains trapped

    Newswise — EVANSTON, Ill. — When physicists steered a tiny microparticle toward a cylindrical obstacle, they expected one of two outcomes to occur. The particle would either collide into the obstacle or sail around it. The particle, however, did neither.

    The researcher team — led by Northwestern University and École Polytechnique in France — was surprised and puzzled to watch the particle curve around the obstacle and then stick to its backside. The obstacle, it seemed, had the particle effectively trapped.

    After a series of simulations and experiments, the researchers unraveled the physics at play behind this strange phenomenon. Three factors caused the unexpected trapping behavior: electrostatics, hydrodynamics and erratic random movement of the surrounding molecules. The size of the obstacle also determined how long the particle remained trapped before escaping.

    The new insights could be leveraged to advance microfluidic applications and drug delivery systems — both of which rely on microparticles to navigate complex, structured landscapes.

    The study will be published March 8 in the journal Science Advances.

    “I didn’t expect to see trapping in this system at all,” said Northwestern’s Michelle Driscoll, who co-led the study. “But trapping adds a lot of utility to the system because now we have a way to gather up particles. Tasks like trapping, mixing and sorting are very difficult to do at such small scales. You can’t just scale down standard processes for mixing and sorting because a different kind of physics kicks in at this size limit. So, it’s important to have different ways to manipulate particles.”

    Driscoll is an assistant professor of physics at Northwestern’s Weinberg College of Arts and Sciences. She co-led the study with Blaise Delmotte, a researcher at École Polytechnique.

    Similar in size to bacteria, microrollers are synthetic, microscopic particles with the ability to move in a fluid environment. Driscoll and her team are particularly interested in microrollers for their ability to move freely — and quickly — in different directions and their potential to carry and deliver cargo in complex, confined environments, including within the human body.

    The microrollers in Driscoll’s lab are plastic with an iron oxide core, which gives them a weak magnetic field. By putting the microrollers in a sealed microchamber (100 millimeters by 2 millimeters by 0.1 millimeters in size), researchers can control the direction they move by manipulating a rotating magnetic field around the sample. To change the way the microrollers move, researchers simply reprogram the motion of the magnetic field to pull the microrollers in different directions.

    But microfluidic devices and the human body are, of course, much more complex landscapes compared to a featureless sample chamber. So, Driscoll and her collaborators added obstacles to the system to see how microrollers could navigate the environment.

    “For true-to-life applications, you aren’t just going to have this system with particles sitting in an open space,” Driscoll said. “It’s going to be a complex landscape. You might have to move the particles through winding channels. So, we wanted to first explore the simplest version of the problem: One microroller and one obstacle.”

    In both computer simulations and the experimental environment, Driscoll and her team added cylindrical obstacles to the sample chamber. Sometimes the microroller sailed around the obstacle without issue, but other times it would swing around the obstacle and then get trapped behind it.

    “We watched the particle stop moving past the obstacle and kind of get stuck,” Driscoll said. “We saw the same behavior in the simulations and in the experiments.”

    By changing the parameters within the simulations and analyzing the data, Driscoll and her team found the hydrodynamics of the fluid inside the sample chamber created stagnant areas. In other words, the spinning microroller caused the fluid to flow in the chamber. But the flows also created pockets — including one directly behind the obstacle — where the fluid remained still and unflowing. When the particle entered the stagnant area, it stopped moving and became stuck.

    But to reach the stagnant area, the particle had to perform a baffling U-turn. After moving past the obstacle, the microroller curved around it, becoming stuck to its backside. Driscoll found that random motions (called Brownian motion) of the molecules within the fluid “kicked” the microroller into the stagnant area.

    “Tiny materials are subject to Brownian fluctuations,” Driscoll explained. “The fluid is not actually a continuum but is composed of individual, little molecules. Those molecules are constantly ramming into the particle at random orientations. If the particle is small enough, these collisions can move it. That’s why if you look at tiny particles under a microscope, they look like they are juggling around a little bit.”

    Driscoll’s team also found that the size of the obstacle controls how long the particle will remain trapped before escaping. For example, it’s easier for Brownian fluctuations to kick the particle into the trapping region when the obstacle is smaller. By changing the obstacle size, researchers can increase the trapping time by orders of magnitude.

    “Usually, Brownian fluctuations are destructive to experiments because they are a source of noise,” Driscoll said. “Here, we can leverage Brownian motion to do something useful. We can enable this hydrodynamic trapping effect.”

    The study, “A simple catch: Fluctuations enable hydrodynamic trapping of microrollers by obstacles,” was supported by the National Science Foundation under award number CBET-1706562, “la Caixa” Foundation (award numbers 100010434 and fellowship LCF/BQ/-PI20/11760014), the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant (award number 847648), the French National Research Agency (award number ANR- 20-CE30-0006) and the NVIDIA Academic Partnership.

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    Northwestern University

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  • Hitting Nuclei with Light May Create Fluid Primordial Matter

    Hitting Nuclei with Light May Create Fluid Primordial Matter

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    The Science

    A new analysis supports the idea that particles of light (photons) colliding with heavy ions create a fluid of “strongly interacting” particles. The calculations are based on the hydrodynamic particle flow seen in collisions of various types of ions at both the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC). With only modest changes, these calculations also describe flow patterns seen in near-miss collisions at the LHC. In these collisions, photons that form a cloud around the speeding ions collide with the ions in the opposite beam.

    The Impact

    The results indicate that photon-heavy ion collisions can create a strongly interacting fluid that responds to the initial collision geometry, exhibiting hydrodynamic behavior. This further means that these collisions can form a quark-gluon plasma, a system of quarks and gluons liberated from the protons and neutrons that make up the ions. These findings will help guide future experiments at the Electron-Ion Collider (EIC), a facility planned to be built at Brookhaven National Laboratory over the next decade.

    Summary

    It may seem surprising that photon-heavy ion collisions can produce a hot and dense fluid. But it’s possible because a photon can undergo quantum fluctuations to become another particle with the same quantum numbers. A likely example is a rho meson, made of a quark and antiquark held together by gluons. When a rho meson collides with a nucleus, it forms a collision system very similar to a proton-nucleus collision, which also exhibits flow-like signals.

    The current analysis by theorists at Brookhaven National Laboratory and Wayne State University sought to explain data from the ATLAS experiment at the LHC. The theorists found that accounting for the energy difference between the rho meson and the much higher energy of the incoming nucleus was the most important ingredient for their calculations’ ability to reproduce the experimental results. In the most energetic heavy ion collisions, the pattern of particles emerging transverse to the colliding beams generally persists no matter how far you look from the collision point along the beamline. But in lower-energy photon-lead collisions, the model showed that the geometry of the particle distributions changes rapidly with increasing longitudinal distance. This decorrelation had a large effect on the observed flow pattern, showing that 3D hydrodynamic modeling is essential for simulating these low energy photon-lead collisions.

     

    Funding

    This research was funded by Department of Energy Office of Science, Office of Nuclear Physics and the National Science Foundation. The research used computational resources of the Open Science Grid, supported by the National Science Foundation.


    Journal Link: Physical Review Letters

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    Department of Energy, Office of Science

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  • Proposed quantum device may succinctly realize emergent particles such as the Fibonacci anyon

    Proposed quantum device may succinctly realize emergent particles such as the Fibonacci anyon

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    Newswise — Long before Dr. Jukka Vayrynen was an assistant professor at the Purdue Department of Physics and Astronomy, he was a post-doc investigating a theoretical model with emergent particles in a condensed matter setting. Once he arrived at Purdue, he intended to expand on the model, expecting it to be relatively easy. He gave the seemingly straightforward calculations to Guangjie Li, a graduate student working with Vayrynen, but the calculations yielded an unexpected result.  These results were a surprising roadblock which nearly brought their research to a screeching halt.  Team tenacity has taken this roadblock and turned it into a possible route to the development of quantum computing.

    At the Aspen Center for Physics in Colorado, Vayrynen discussed this issue with a colleague from the Weizmann Institute of Science in Israel, Dr. Yuval Oreg, who helped circumvent the obstacle. The team used this new understanding of their calculations to propose a quantum device that could be tested experimentally to succinctly realize emergent particles such as the Fibonacci anyon. They have published their findings, “Multichannel topological Kondo effect,” in Physical Review Letters on February 10, 2023.

    Condensed matter theory is a field of physics that studies, for example, the properties of electronic quantum systems, with applications to technologies such as superconductors, transistors, or quantum computing devices. One of the challenges in this field is understanding the quantum mechanical behavior of many electrons, also known as the “many-body problem.” It is a problem because it can only be theoretically modeled in very limited cases. However, even in those limited cases, rich emergent phenomena such as collective excitations or fractionally charged emergent “quasi”-particles are known to emerge. These phenomena are a result of the complex interactions between electrons and can lead to the development of new materials and technologies.

    “In our paper, we propose a quantum device that is simple enough to be theoretically modeled and tested experimentally in the future, yet also complex enough to display non-trivial emergent particles,” says Vayrynen. “Our results indicate that the proposed device can realize an emergent particle called a Fibonacci anyon that can be used as a building block of a quantum computer. The device is therefore a promising candidate for the development of quantum computing technology.”

    This discovery could be used in future quantum computers in a way that allows one to make them more resistant to decoherence, a.k.a. noise.

    According to their publication, the team introduced a physically motivated N-channel generalization of a topological Kondo model.  Starting from the simplest case N = 2, they conjecture a stable intermediate coupling fixed point and evaluate the resulting low-temperature impurity entropy. The impurity entropy indicates that an emergent Fibonacci anyon can be realized in the N = 2 model. 

    According to Li, “a Fibonacci anyon is an emergent particle with the property that as you add more particles to the system, the number of quantum states grows like the Fibonacci sequence, 1, 2, 3, 5, 8, etc. In our system, a small quantum device is connected to conduction electron leads which will overly screen the device and can result in an emergent Fibonacci anyon.”

    The team also gives a number of predictions that could be experimentally tested in future quantum devices.

     “We evaluate the zero-temperature impurity entropy and conductance to obtain experimentally observable signatures of our results. In the large-N limit we evaluate the full cross over function describing the temperature-dependent conductance,” says Vayrynen.

    This research is the first in a series that the Purdue team of Li and Vayrynen will work on. They collaborated with a senior scientist from Max Planck Institute for Solid State Research in Germany, Dr. Elio König, and posted a related work, “Topological Symplectic Kondo Effect,” in a preprint arXiv (2210.16614) on October 20, 2022.

    This research was based on work supported by the Quantum Science Center, a U.S. Department of Energy National Quantum Information Science Research Center headquartered at DOE’s Oak Ridge National Laboratory. Dr. Yong Chen, the Karl Lark-Horovitz Professor of Physics and Astronomy and Professor of Electrical and Computer Engineering, is on the QSC’s Governance Advisory Board, and Purdue is one of the center’s core partners.

    About the Department of Physics and Astronomy at Purdue University

    Purdue Department of Physics and Astronomy has a rich and long history dating back to 1904. Our faculty and students are exploring nature at all length scales, from the subatomic to the macroscopic and everything in between. With an excellent and diverse community of faculty, postdocs, and students who are pushing new scientific frontiers, we offer a dynamic learning environment, an inclusive research community, and an engaging network of scholars.  

    Physics and Astronomy is one of the seven departments within the Purdue University College of Science. World-class research is performed in astrophysics, atomic and molecular optics, accelerator mass spectrometry, biophysics, condensed matter physics, quantum information science, particle and nuclear physics. Our state-of-the-art facilities are in the Physics Building, but our researchers also engage in interdisciplinary work at Discovery Park District at Purdue, particularly the Birck Nanotechnology Center and the Bindley Bioscience Center.  We also participate in global research including at the Large Hadron Collider at CERN, Argonne National Laboratory, Brookhaven National Laboratory, Fermilab, the Stanford Linear Accelerator, the James Webb Space Telescope, and several observatories around the world. 

    About Purdue University

    Purdue University is a top public research institution developing practical solutions to today’s toughest challenges. Ranked in each of the last five years as one of the 10 Most Innovative universities in the United States by U.S. News & World Report, Purdue delivers world-changing research and out-of-this-world discovery. Committed to hands-on and online, real-world learning, Purdue offers a transformative education to all. Committed to affordability and accessibility, Purdue has frozen tuition and most fees at 2012-13 levels, enabling more students than ever to graduate debt-free. See how Purdue never stops in the persistent pursuit of the next giant leap at https://stories.purdue.edu.

     

    Contributors:

    Dr. Jukka Vayrynen, Assistant Professor of Physics and Astronomy

    Guangjie Li, Graduate Student

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  • A quasiparticle that can transfer heat under electrical control

    A quasiparticle that can transfer heat under electrical control

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    Newswise — COLUMBUS, Ohio – Scientists have found the secret behind a property of solid materials known as ferroelectrics, showing that quasiparticles moving in wave-like patterns among vibrating atoms carry enough heat to turn the material into a thermal switch when an electrical field is applied externally.

    A key finding of the study is that this control of thermal conductivity is attributable to the structure of the material rather than any random collisions among atoms. Specifically, the researchers describe quasiparticles called ferrons whose polarization changes as they “wiggle” in between vibrating atoms – and it’s that ordered wiggling and polarization, receptive to the externally applied electrical field, that dictates the material’s ability to transfer the heat at a different rate. 

    “We figured out that this change in position of these atoms, and the change of the nature of the vibrations, must carry heat, and therefore the external field which changes this vibration must affect the thermal conductivity,” said senior author Joseph Heremans, professor of mechanical and aerospace engineering, materials science and engineering, and physics at The Ohio State University.  

    “People tend to think atom vibrations are a given fact and don’t respond to an electric field or a magnetic field. And we are saying you can affect them with an electric field.” 

    With the use of a simple external electrical stimulus, the thermal conductivity in this type of material can be changed at room temperature rather than at the extremely low temperatures required to control most candidate materials for solid-state heat switches, enhancing the possibilities for real-world applications of the technology, the researchers say. 

    The study is published Feb. 1, 2023, in the journal Science Advances. 

    The material used in the study is a common lead zirconium titanate ceramic belonging to a class of materials called piezoelectrics, which change shape when an electric field is applied to them or produce an electrical charge under mechanical stress. 

    Ferroelectrics, a subset of piezoelectrics, are materials in which the electrical charges on the atoms can spontaneously form electrical dipoles that all align in the same direction, forming what is known as polarization. These dipoles can be switched by an external electric field.  

    Until now, scientists had not formally written down how this polarization will move when heat is applied. In this new article, this motion is described by introducing the quasiparticle – called a ferron – that carries waves of polarization and heat at the same time. The ferron is sensitive to an external electric field, and that means the application of an external electrical field can turn the material into a heat switch. 

    “The quasiparticle has always been there. It just hasn’t been identified and measured,” said first author Brandi Wooten, a PhD student in materials science and engineering at Ohio State. 

    Wooten likened ferrons’ behavior to a stadium wave, with each sports fan representing a cell of atoms collected together in a crystal. 

    “You have all these atoms, and they have this special dipole – an atom with an electrical charge that moves up and down creates a dipole. You can think of people’s hands going up doing the wave as the dipole’s strength – if their hands are up, it’s really strong. If they’re a little bit down, it’s weaker, and if they’re all the way down, it’s negative,” she said. “That’s the dipole’s strength. We found that these special waves carry both heat and polarization, and we labeled them ferrons.” 

    This heat-transferring property is induced by the electric field through a phenomenon known as the piezoelectric strain: The lattice contracts or stretches when the voltage is applied, with atoms and forces between them moving back and forth, ultimately changing the mechanical properties of the material and, as a result, changing its thermal conductivity, said Heremans, also an Ohio Eminent Scholar in Nanotechnology. 

    “The ferron is also sensitive to strain in the solid. Since the ferron carries heat, that makes the amount of heat carried dependent on the electrical field,” he said. “So we wrote a new theory that relates an external electric field, the strain it induces in a ferroelectric, and ultimately how this strain affects the thermal conductivity.” 

    The theory is predictive, so researchers can now use it to find materials where the effect is much larger, ultimately leading to materials where it is large enough to be used in heat switches in everyday applications, like collection of solar power. 

    The application of an electrical field to the material produced a 2% difference between maximum and minimum conductivity – as the new theory predicted would be the case. A series of experiments quantifying the atomic vibrations through measuring the velocity of the material’s sound waves and equilibrium and transport properties validated “that this all depends only on the material structure, not necessarily what’s scattering the vibrations,” Wooten said.

    The researchers are now studying other materials that might increase that change in thermal conductivity by up to 15%, as the new theory predicts. 

    “Any application depends on us finding a material where the effect is much larger,” Heremans said. “We are looking for materials that have the right parameters.”

    This work was supported by the National Science Foundation, the U.S. Department of Defense, the Japanese Society for the Promotion of Science and the Japanese Science and Technology Agency. 

    Additional co-authors include Ryo Iguchi and Ken-ichi Uchida of the National Institute for Materials Science in Japan; Ping Tang and Gerrit Bauer of Tohoku University; and Joon Sang Kang of Ohio State.

     

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  • Celebrating the Upcoming sPHENIX Detector

    Celebrating the Upcoming sPHENIX Detector

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    Newswise — UPTON, NY— Asmeret Asefaw Berhe, Director of the U.S. Department of Energy’s (DOE) Office of Science, visited DOE’s Brookhaven National Laboratory on Jan. 27 to celebrate the fast-approaching debut of a state-of-the-art particle detector known as sPHENIX. The house-sized, 1000-ton detector is slated to begin collecting data at Brookhaven Lab’s Relativistic Heavy Ion Collider (RHIC), a DOE Office of Science User Facility for nuclear physics research, this spring.

    Like a massive, 3D digital camera, sPHENIX will capture snapshots of 15,000 particle collisions per second to provide scientists with data to better understand the properties of quark-gluon plasma (QGP)—an ultra-hot and ultra-dense soup of subatomic particles that are the building blocks of nearly all visible matter. RHIC collisions briefly recreate the conditions of the universe a fraction of a second after the Big Bang, some 14 billion years ago. Studying QGP can help physicists learn about the origins of matter as we know it and how nature’s strongest force binds quarks and gluons into protons and neutrons, the particles that make up ordinary atomic nuclei.  

    “Brookhaven National Laboratory continues to be a central hub of nuclear physics expertise, making it the world’s premier facility for studying the quark gluon plasma,” said Asmeret Asefaw Berhe, DOE’s Director of the Office of Science. “The sPHENIX detector, and the talented collaboration that will operate it, will strive to give us that answer and the final piece of the quark-gluon puzzle.”

    Brookhaven Lab Director Doon Gibbs said, “sPHENIX marks a key milestone in the RHIC science program. It will allow us to explore many questions raised by incredible discoveries already made at RHIC, especially the surprising liquid nature of the quark-gluon plasma, and lay the foundation for future discoveries at the Electron-Ion Collider. I congratulate and thank all the scientists, engineers, technicians, and support staff at Brookhaven—and sPHENIX collaborators around the world—who have worked together to make this detector possible.”

    At the core of sPHENIX is a 20-ton cylindrical superconducting magnet that will bend the trajectories of charged particles produced in RHIC collisions. The magnet is surrounded and filled with subsystems that include complex silicon detectors, a Time Projection Chamber, and calorimeters that will capture details of particle jets, heavy quarks, and rare, high-momentum particles fast and accurately. These advanced particle tracking systems will allow nuclear physicists to probe properties of the quark-gluon plasma with higher precision than ever before to understand how the interactions between quarks and gluons give rise to the unique, liquid-like behavior of QGP.

    “Our detector employs 100,000 silicon photomultipliers, calorimeter elements built using 3-D printing techniques and a 300 million channel radiation-hard silicon detector that has its sensor and electronics integrated into a monolithic device,” said sPHENIX project director Ed O’Brien.

    Many sPHENIX detector components build on experience gained throughout RHIC operations and draw on expertise throughout the nuclear and particle physics communities, including running experiments at Europe’s Large Hadron Collider.

    “These technologies were barely on the drawing board when RHIC began operations over 20 years ago,” O’Brien said. “Now they are a reality in sPHENIX.”

    “We’ve pulled together the field’s most sophisticated technologies and pushed them to new limits to design a detector unlike any that have come before,” said Brookhaven Lab physicist and sPHENIX co-spokesperson David Morrison. “It’s really a technological marvel.”

    sPHENIX will generate an enormous amount of data to realize its science goals. Developing the capabilities to collect, store, share, and analyze that data will help push the limits of data handling in ways that could benefit other fields including climate modeling, public health, and any fields that require the analysis of huge datasets.

    Learn more about sPHENIX and watch as some of its components came together.

    sPHENIX was built by an international collaboration of physicists, engineers, and technicians from 80 universities and labs from 14 countries—close to 400 collaborators overall, including students. Students, for example, joined efforts to assemble and test complex detector subsystems, studied cost-effective materials for high-speed electronics, and contributed to accelerator improvements that will increase collision rates at RHIC.

    “These hands-on educational experiences are providing valuable training for our nation’s future scientists, technicians, and engineers,” said sPHENIX co-spokesperson Gunther Roland, a physicist at the Massachusetts Institute of Technology. “Their expertise and future work may impact fields well beyond fundamental physics that rely on similar sophisticated electronics and cutting-edge technologies—including medical imaging and national security.”

    sPHENIX and operations at RHIC are funded by the DOE Office of Science (NP). 

    Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov. 

    Follow @BrookhavenLab on Twitter or find us on Facebook. 

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  • Physicists observe global spin alignment in heavy-ion collisions

    Physicists observe global spin alignment in heavy-ion collisions

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    Newswise — Physicists from the STAR Collaboration have reported the first observation of a global spin alignment signal in heavy-ion collisions. Published in Nature on Jan. 18, the study provides a potential new avenue for understanding the strong interaction at work at the sub-nucleon level. 

    The STAR (Solenoidal Tracker at RHIC) Experiment is based at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). The STAR Collaboration comprises 717 collaborators from 71 institutions in 14 countries.  

    This study was performed by researchers from the Institute of Modern Physics of the Chinese Academy of Sciences, Fudan University, BNL, Kent State University, and the University of Illinois Chicago. 

    As its name implies, the strong force is the strongest of the four fundamental forces in nature. It’s what holds together the building blocks of atoms—the protons and neutrons that make up atomic nuclei, as well as their inner building blocks, quarks and gluons. 

    At RHIC, heavy ions (e.g., gold nuclei) were accelerated to close to the speed of light and collided from opposite directions. The collisions “melted” the boundaries of individual protons and neutrons, setting free the quarks and gluons normally confined within to create a quark-gluon plasma (QGP). 

    In collisions that are not exactly head-on, the colliding system generates a very large orbital angular momentum (OAM). Part of the OAM is transferred to the preferential alignment of the spin of particles along the OAM direction. Since the STAR detector couldn’t directly measure the spin direction, the physicists measured the spin alignment of these particles by tracking the distribution of their decay products relative to the direction perpendicular to the reaction plane of the colliding nuclei. 

    In this study, the researchers measured the spin alignment of the phi and the K*0 mesons. For these particles, there are three possible orientations along the OAM. If no special physics mechanism presents, the probability of each of these three states should be equal to one-third. 

    The researchers found that there was no preference for the K*0 mesons. However, the phi mesons showed a strong signal of global spin alignment, which increased with decreasing collision energy, clearly indicating that they prefer one state over the other two. It is the first time ever that such an alignment has been observed in heavy-ion collisions. 

    The surprising spin-alignment pattern and magnitude for phi mesons cannot be explained by conventional mechanisms, such as the magnetic field strength, vorticity or fragmentation of polarized quarks. 

    Theorists recently came up with the idea that local fluctuations in the strong force within the quark-gluon plasma could be driving the phi mesons’ apparent spin alignment preference. This explanation is still under debate and further experimental verification is needed. This connection, if fully established, will open a potential new avenue for studying the behavior of strong force fields. 

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