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  • richardmitnick 12:14 pm on August 25, 2017 Permalink | Reply
    Tags: , Basic science research seeks to improve our understanding of the world around us, , BNL RHIC, Center for Frontiers of Nuclear Science, , , Nucleons, ,   

    From BNL: “Research Center Established to Explore the Least Understood and Strongest Force Behind Visible Matter” 

    Brookhaven Lab

    August 22, 2017
    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174

    1
    In an Electron-Ion Collider, a beam of electrons (e-) would scatter off a beam of protons or atomic nuclei, generating virtual photons (λ)—particles of light that penetrate the proton or nucleus to tease out the structure of the quarks and gluons within.

    Science can explain only a small portion of the matter that makes up the universe, from the earth we walk on to the stars we see at night. Stony Brook University and the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory (BNL) have established the Center for Frontiers of Nuclear Science to help scientists better understand the building blocks of visible matter. The new Center will push the frontiers of knowledge about quarks, gluons and their interactions that form protons, neutrons, and ultimately 99.9 percent of the mass of atoms – the bulk of the visible universe.

    “The Center for Frontiers in Nuclear Science will bring us closer to understanding our universe in ways in which it has never before been possible,” said Samuel L. Stanley Jr., MD, President of Stony Brook University. “Thanks to the vision of the Simons Foundation, scientists from Stony Brook, Brookhaven Laboratory and many other institutions are now empowered to pursue the big ideas that will lead to new knowledge about the structure of the building blocks of everything in the universe today.”

    Bolstered by a new $5 million grant from the Simons Foundation and augmented by $3 million in research grants received by Stony Brook University, the Center will be a research and education hub to ultimately help scientists unravel more secrets of the universe’s strongest and least-understood force to advance both fundamental science and applications that transform our lives.

    Jim Simons, PhD, Chairman of the Simons Foundation said, “Nuclear physics is a deep and important discipline, casting light on many poorly understood facets of matter in our universe. It is a pleasure to support research in this area conducted by members of the outstanding team to be assembled by Brookhaven Lab and Stony Brook University. We much look forward to the results of this effort.”

    “Basic science research seeks to improve our understanding of the world around us, and it can take human understanding to wonderful and unexpected places,” said Marilyn Simons, President of the Simons Foundation. “Exploring the qualities and behaviors of fundamental particles seems likely to do just that.”

    The Center brings together current Stony Brook faculty and BNL staff, and scientists around the world with students and new scientific talent to investigate the structure of nucleons and nuclei at a fundamental level. Despite the importance of nucleons in all visible matter, scientists know less about their internal structure and dynamics than about any other component of visible matter. Over the next several decades, the Center is slated to become a leading international intellectual hub for quantum chromodynamics (QCD), a branch of physics that describes the properties of nucleons, starting from the interactions of the quarks and gluons inside them.

    2
    An Electron-Ion Collider would probe the inner microcosm of protons to help scientists understand how interactions among quarks (colored spheres) and glue-like gluons (yellow) generate the proton’s essential properties and the large-scale structure of the visible matter in the universe today.

    As part of the Center’s mission as a destination of research, collaboration and education for international scientists and students, workshops and seminars are planned for scientists to discuss and investigate theoretical concepts and promote experimental measurements to advance QCD-based nuclear science. The Center will support graduate education in nuclear science and conduct visitor programs to support and promote the Center’s role as an international research hub for physics related to a proposed Electron Ion Collider (EIC).

    One of the central aspects of the Center’s focus during its first few years will be activities on the science of a proposed EIC, a powerful new particle accelerator that would create rapid-fire, high-resolution “snapshots” of quarks and gluons contained in nucleons and complex nuclei. An EIC would enable scientists to see deep inside these objects and explore the still mysterious structures and interactions of quarks and gluons, opening up a new frontier in nuclear physics.

    “The role of quarks and gluons in determining the properties of protons and neutrons remains one of the greatest unsolved mysteries in physics,” said Doon Gibbs, Ph.D., Brookhaven Lab Director. “An Electron Ion Collider would reveal the internal structure of these atomic building blocks, a key part of the quest to understand the matter we’re made of.”

    Building an EIC and its research program in the United States would strengthen and expand U.S. leadership in nuclear physics and stimulate economic benefits well into the 2040s. In 2015, the DOE and the National Science Foundation’s Nuclear Science Advisory Committee recommended an EIC as the highest priority for new facility construction. Similar to explorations of fundamental particles and forces that have driven our nation’s scientific, technological, and economic progress for the past century — from the discovery of electrons that power our sophisticated computing and communications devices to our understanding of the cosmos — groundbreaking nuclear science research at an EIC will spark new innovations and technological advances.

    Stony Brook and BNL have internationally renowned programs in nuclear physics that focus on understanding QCD. Stony Brook’s nuclear physics group has recently expanded its expertise by adding faculty in areas such as electron scattering and neutrino science. BNL operates the Relativistic Heavy Ion Collider, a DOE Office of Science User Facility and the world’s most versatile particle collide. RHIC has pioneered the study of quark-gluon matter at high temperatures and densities—known as quark-gluon plasma— and is exploring the limits of normal nuclear matter. Together, these cover a major part of the course charted by the U.S. nuclear science community in its 2015 Long Range Plan.

    Abhay Deshpande, PhD, Professor of experimental nuclear physics in the Department of Physics and Astronomy in the College of Arts and Sciences at Stony Brook University, has been named Director of the Center. Professor Deshpande has promoted an EIC for more than two decades and helped create a ~700-member global scientific community (the EIC Users Group, EICUG) interested in pursuing the science of an EIC. In the fall of 2016, he was elected as the first Chair of its Steering Committee, effectively serving as its spokesperson, a position from which he has stepped down to direct the new Center. Concurrently with his position as Center Director, Dr. Deshpande also serves as Director of EIC Science at Brookhaven Lab.

    Scientists at the Center, working with EICUG, will have a specific focus on QCD inside the nucleon and how it shapes fundamental nucleon properties, such as spin and mass; the role of high-density many-body QCD and gluons in nuclei; the quark-gluon plasma at the high temperature frontier; and the connections of QCD to weak interactions and nuclear astrophysics. Longer term, the Center’s programmatic focus is expected to reflect the evolution of nuclear science priorities in the United States.

    See the full article here .

    Please help promote STEM in your local schools.

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    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 5:12 pm on June 29, 2017 Permalink | Reply
    Tags: , , , BNL RHIC, , , , HPSS -High Performance Storage System, , , , RACF - Resource Access Control Facility, Scientific Data and Computing Center   

    From BNL: “Brookhaven Lab’s Scientific Data and Computing Center Reaches 100 Petabytes of Recorded Data” 

    Brookhaven Lab

    Ariana Tantillo
    atantillo@bnl.gov

    Total reflects 17 years of experimental physics data collected by scientists to understand the fundamental nature of matter and the basic forces that shape our universe.

    1
    (Back row) Ognian Novakov, Christopher Pinkenburg, Jérôme Lauret, Eric Lançon, (front row) Tim Chou, David Yu, Guangwei Che, and Shigeki Misawa at Brookhaven Lab’s Scientific Data and Computing Center, which houses the Oracle StorageTek tape storage system where experimental data are recorded.

    Imagine storing approximately 1300 years’ worth of HDTV video, nearly six million movies, or the entire written works of humankind in all languages since the start of recorded history—twice over. Each of these quantities is equivalent to 100 petabytes of data: the amount of data now recorded by the Relativistic Heavy Ion Collider (RHIC) and ATLAS Computing Facility (RACF) Mass Storage Service, part of the Scientific Data and Computing Center (SDCC) at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory. One petabyte is defined as 10245 bytes, or 1,125,899,906,842,624 bytes, of data.

    “This is a major milestone for SDCC, as it reflects nearly two decades of scientific research for the RHIC nuclear physics and ATLAS particle physics experiments, including the contributions of thousands of scientists and engineers,” said Brookhaven Lab technology architect David Yu, who leads the SDCC’s Mass Storage Group.

    SDCC is at the core of a global computing network connecting more than 2,500 researchers around the world with data from the STAR and PHENIX experiments at RHIC—a DOE Office of Science User Facility at Brookhaven—and the ATLAS experiment at the Large Hadron Collider (LHC) in Europe.

    BNL/RHIC Star Detector

    BNL/RHIC PHENIX

    CERN/ATLAS detector

    In these particle collision experiments, scientists recreate conditions that existed just after the Big Bang, with the goal of understanding the fundamental forces of nature—gravitational, electromagnetic, strong nuclear, and weak nuclear—and the basic structure of matter, energy, space, and time.

    Big Data Revolution

    The RHIC and ATLAS experiments are part of the big data revolution.

    BNL RHIC Campus


    BNL/RHIC

    These experiments involve collecting extremely large datasets that reduce statistical uncertainty to make high-precision measurements and search for extremely rare processes and particles.

    For example, only one Higgs boson—an elementary particle whose energy field is thought to give mass to all the other elementary particles—is produced for every billion proton-proton collisions at the LHC.

    CERN CMS Higgs Event


    CERN/CMS Detector

    CERN ATLAS Higgs Event

    More, once produced, the Higgs boson almost immediately decays into other particles. So detecting the particle is a rare event, with around one trillion collisions required to detect a single instance. When scientists first discovered the Higgs boson at the LHC in 2012, they observed about 20 instances, recording and analyzing more than 300 trillion collisions to confirm the particle’s discovery.

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    At the end of 2016, the ATLAS collaboration released its first measurement of the mass of the W boson particle (another elementary particle that, together with the Z boson, is responsible for the weak nuclear force). This measurement, which is based on a sample of 15 million W boson candidates collected at LHC in 2011, has a relative precision of 240 parts per million (ppm)—a result that matches the best single-experiment measurement announced in 2007 by the Collider Detector at Fermilab collaboration, whose measurement is based on several years’ worth of collected data. A highly precise measurement is important because a deviation from the mass predicted by the Standard Model could point to new physics. More data samples are required to achieve the level of accuracy (80 ppm) that scientists need to significantly test this model.

    The volume of data collected by these experiments will grow significantly in the near future as new accelerator programs deliver higher-intensity beams. The LHC will be upgraded to increase its luminosity (rate of collisions) by a factor of 10. This High-Luminosity LHC, which should be operational by 2025, will provide a unique opportunity for particle physicists to look for new and unexpected phenomena within the exabytes (one exabyte equals 1000 petabytes) of data that will be collected.

    Data archiving is the first step in making available the results from such experiments. Thousands of physicists then need to calibrate and analyze the archived data and compare the data to simulations. To this end, computational scientists, computer scientists, and mathematicians in Brookhaven Lab’s Computational Science Initiative, which encompasses SDCC, are developing programming tools, numerical models, and data-mining algorithms. Part of SDCC’s mission is to provide computing and networking resources in support of these activities.

    A Data Storage, Computing, and Networking Infrastructure

    Housed inside SDCC are more than 60,000 computing cores, 250 computer racks, and tape libraries capable of holding up to 90,000 magnetic storage tape cartridges that are used to store, process, analyze, and distribute the experimental data. The facility provides approximately 90 percent of the computing capacity for analyzing data from the STAR and PHENIX experiments, and serves as the largest of the 12 Tier 1 computing centers worldwide that support the ATLAS experiment. As a Tier 1 center, SDCC contributes nearly 23 percent of the total computing and storage capacity for the ATLAS experiment and delivers approximately 200 terabytes of data (picture 62 million photos) per day to more than 100 data centers globally.

    At SDCC, the High Performance Storage System (HPSS) has been providing mass storage services to the RHIC and LHC experiments since 1997 and 2006, respectively. This data archiving and retrieval software, developed by IBM and several DOE national laboratories, manages petabytes of data on disk and in robot-controlled tape libraries. Contained within the libraries are magnetic tape cartridges that encode the data and tape drives that read and write the data. Robotic arms load the cartridges into the drives and unload them upon request.

    3
    Inside one of the automated tape libraries at the Scientific Data and Computing Center (SDCC), Eric Lançon, director of SDCC, holds a magnetic tape cartridge. When scientists need data, a robotic arm (the piece of equipment in front of Lançon) retrieves the relevant cartridges from their slots and loads them into drives in the back of the library.

    When ranked by the volume of data stored in a single HPSS, Brookhaven’s system is the second largest in the nation and the fourth largest in the world. Currently, the RACF operates nine Oracle robotic tape libraries that constitute the largest Oracle tape storage system in the New York tri-state area. Contained within this system are nearly 70,000 active cartridges with capacities ranging from 800 gigabytes to 8.5 terabytes, and more than 100 tape drives. As the volume of scientific data to be stored increases, more libraries, tapes, and drives can be added accordingly. In 2006, this scalability was exercised when HPSS was expanded to accommodate data from the ATLAS experiment at LHC.

    “The HPSS system was deployed in the late 1990s, when the RHIC accelerator was coming on line. It allowed data from RHIC experiments to be transmitted via network to the data center for storage—a relatively new idea at the time,” said Shigeki Misawa, manager of Mass Storage and General Services at Brookhaven Lab. Misawa played a key role in the initial evaluation and configuration of HPSS, and has guided the system through significant changes in hardware (network equipment, storage systems, and servers) and operational requirements (tape drive read/write rate, magnetic tape cartridge capacity, and data transfer speed). “Prior to this system, data was recorded on magnetic tape at the experiment and physically moved to the data center,” he continued.

    Over the years, SDCC’s HPSS has been augmented with a suite of optimization and monitoring tools developed at Brookhaven Lab. One of these tools is David Yu’s scheduling software that optimizes the retrieval of massive amounts of data from tape storage. Another, developed by Jérôme Lauret, software and computing project leader for the STAR experiment, is software for organizing multiple user requests to retrieve data more efficiently.

    Engineers in the Mass Storage Group—including Tim Chou, Guangwei Che, and Ognian Novakov—have created other software tools customized for Brookhaven Lab’s computing environment to enhance data management and operation abilities and to improve the effectiveness of equipment usage.

    STAR experiment scientists have demonstrated the capabilities of SDCC’s enhanced HPSS, retrieving more than 4,000 files per hour (a rate of 6,000 gigabytes per hour) while using a third of HPSS resources. On the data archiving side, HPSS can store data in excess of five gigabytes per second.

    As demand for mass data storage spreads across Brookhaven, access to HPSS is being extended to other research groups. In the future, SDCC is expected to provide centralized mass storage services to multi-experiment facilities, such as the Center for Functional Nanomaterials and the National Synchrotron Light Source II—two more DOE Office of Science User Facilities at Brookhaven.

    “The tape library system of SDCC is a clear asset for Brookhaven’s current and upcoming big data science programs,” said SDCC Director Eric Lançon. “Our expertise in the field of data archiving is acknowledged worldwide.”

    See the full article here .

    Please help promote STEM in your local schools.

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    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 2:25 pm on April 24, 2017 Permalink | Reply
    Tags: BNL RHIC, , , , ,   

    From Symmetry: “A tiny droplet of the early universe?” 

    Symmetry Mag

    Symmetry

    04/24/17
    Sarah Charley

    Particles seen by the ALICE experiment hint at the formation of quark-gluon plasma during proton-proton collisions. [ALREADY COVERED WITH AN ARTICLE FROM CERN HERE.]

    1
    Mona Schweizer, CERN

    About 13.8 billion years ago, the universe was a hot, thick soup of quarks and gluons—the fundamental components that eventually combined into protons, neutrons and other hadrons.

    Scientists can produce this primitive particle soup, called the quark-gluon plasma, in collisions between heavy ions. But for the first time physicists on an experiment at the Large Hadron Collider have observed particle evidence of its creation in collisions between protons as well.

    The LHC collides protons during the majority of its run time. This new result, published in Nature Physics by the ALICE collaboration, challenges long-held notions about the nature of those proton-proton collisions and about possible phenomena that were previously missed.

    “Many people think that protons are too light to produce this extremely hot and dense plasma,” says Livio Bianchi, a postdoc at the University of Houston who worked on this analysis. “But these new results are making us question this assumption.”

    Scientists at the LHC and at the US Department of Energy’s Brookhaven National Laboratory’s Relativistic Heavy Ion Collider, or RHIC, have previously created quark-gluon plasma in gold-gold and lead-lead collisions.

    BNL RHIC Campus

    BNL/RHIC Star

    BNL RHIC PHENIX

    CERN/LHC Map

    CERN LHC Tunnel


    CERN LHC

    In the quark gluon plasma, mid-sized quarks—such as strange quarks—freely roam and eventually bond into bigger, composite particles (similar to the way quartz crystals grow within molten granite rocks as they slowly cool). These hadrons are ejected as the plasma fizzles out and serve as a telltale signature of their soupy origin. ALICE researchers noticed numerous proton-proton collisions emitting strange hadrons at an elevated rate.

    “In proton collisions that produced many particles, we saw more hadrons containing strange quarks than predicted,” says Rene Bellwied, a professor at the University of Houston. “And interestingly, we saw an even bigger gap between the predicted number and our experimental results when we examined particles containing two or three strange quarks.”

    From a theoretical perspective, a proliferation of strange hadrons is not enough to definitively confirm the existence of quark-gluon plasma. Rather, it could be the result of some other unknown processes occurring at the subatomic scale.

    “This measurement is of great interest to quark-gluon-plasma researchers who wonder how a possible QGP signature can arise in proton-proton collisions,” says Urs Wiedemann, a theorist at CERN. “But it is also of great interest for high energy physicists who have never encountered such a phenomenon in proton-proton collisions.”

    Earlier research at the LHC found that the spatial orientation of particles produced during some proton-proton collisions mirrored the patterns created during heavy-ion collisions, suggesting that maybe these two types of collisions have more in common than originally predicted. Scientists working on the ALICE experiment will need to explore multiple characteristics of these strange proton-proton collisions before they can confirm if they are really seeing a miniscule droplet of the early universe.

    “Quark-gluon plasma is a liquid, so we also need to look at the hydrodynamic features,” Bianchi says. “The composition of the escaping particles is not enough on its own.”

    This finding comes from data collected the first run of the LHC between 2009 and 2013. More research over the next few years will help scientists determine whether the LHC can really make quark-gluon plasma in proton-proton collisions.

    “We are very excited about this discovery,” says Federico Antinori, spokesperson of the ALICE collaboration. “We are again learning a lot about this extreme state of matter. Being able to isolate the quark-gluon-plasma-like phenomena in a smaller and simpler system, such as the collision between two protons, opens up an entirely new dimension for the study of the properties of the primordial state that our universe emerged from.”

    Other experiments, such as those using RHIC, will provide more information about the observable traits and experimental characteristics of quark-gluon plasmas at lower energies, enabling researchers to gain a more complete picture of the characteristics of this primordial particle soup.

    “The field makes far more progress by sharing techniques and comparing results than we would be able to with one facility alone,” says James Dunlop, a researcher at RHIC. “We look forward to seeing further discoveries from our colleagues in ALICE.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 10:04 am on March 10, 2017 Permalink | Reply
    Tags: , , , BNL RHIC, , , , , , , Xiaofeng Guo   

    From Brookhaven: Women in STEM – “Secrets to Scientific Success: Planning and Coordination” Xiaofeng Guo 

    Brookhaven Lab

    March 8, 2017
    Lida Tunesi

    1
    Xiaofeng Guo

    Very often there are people behind the scenes of scientific advances, quietly organizing the project’s logistics. New facilities and big collaborations require people to create schedules, manage resources, and communicate among teams. The U.S. Department of Energy’s Brookhaven National Laboratory is lucky to have Xiaofeng Guo in its ranks—a skilled project manager who coordinates projects reaching across the U.S. and around the world.

    Guo, who has a Ph.D. in theoretical physics from Iowa State University, is currently deputy manager for the U.S. role in two upgrades to the ATLAS detector, one of two detectors at CERN’s Large Hadron Collider that found the Higgs boson in 2012.


    CERN ATLAS Higgs Event


    CERN/ATLAS detector

    Brookhaven is the host laboratory for both U.S. ATLAS Phase I and High Luminosity LHC (HL-LHC) upgrade projects, which involve hundreds of millions of dollars and 46 institutions across the nation. The upgrades are complex international endeavors that will allow the detector to make use of the LHC’s ramped up particle collision rates. Guo keeps both the capital and the teams on track.

    “I’m in charge of all business processes, project finance, contracts with institutions, baseline plan reports, progress reports—all aspects of business functions in the U.S. project team. It keeps me very busy,” she laughed. “In the beginning I was thinking ‘in my spare time I can still read physics papers, do my own calculations’… And now I have no spare time!”

    Guo’s dual interest in physics and management developed early in her career.

    “When I was an undergraduate there was a period when I actually signed up for a double major, with classes in finance and economics in addition to physics,” Guo recalled. “I’m happy to explore different things!”

    Later, while teaching physics part-time at Iowa State University, Guo desired career flexibility and studied to be a Chartered Financial Analyst. She passed all required exams in just two years but decided to continue her research after receiving a grant from the National Science Foundation.

    Guo joined Brookhaven Lab in 2010 to fill a need for project management in Nuclear and Particle Physics (NPP). The position offered her a way to learn new skills while staying up-to-date on the physics world.

    Early in her time at Brookhaven, Guo participated in the management of the Heavy Flavor Tracker (HFT) upgrade to the STAR particle detector at the Relativistic Heavy Ion Collider (RHIC), a DOE Office of Science User Facility for nuclear physics research. The project was successfully completed $600,000 under budget and a whole year ahead of schedule.


    BNL/RHIC Star Detector

    “This was a very good learning experience for me. I participated in all the manager meeting discussions, updated the review documents, and helped them handle some contracts. Through this process I learned all the DOE project rules,” Guo said.

    While working on the HFT upgrade, Guo also helped develop successful, large group proposals for increased computational resources in high-energy physics and other fields of science. She joined the ATLAS Upgrade projects after receiving her Project Management Certification, and her physics and finance background as well as experience with large collaborations have enabled her to orchestrate complex planning efforts.

    For the two phases of the U.S. ATLAS upgrade, Guo directly coordinates more than 140 scientists, engineers, and finance personnel, and oversees all business processes, including finance, contracts, and reports. And taking her job one step further, she’s developed entirely new management tools and reporting procedures to keep the multi-institutional effort synchronized.

    “Dr. Guo is one of our brightest stars,” said Berndt Mueller, Associate Lab Director of NPP. “We are fortunate to have her to assist us with many challenging aspects of project development and execution in NPP. In the process of guiding the work of scores of scientists and engineers, she has single-handedly created a unique and essential role in the development of complex projects with an international context, demonstrating skills of unusual depth and breadth and the ability to apply them across a wide array of disciplines.”

    Guo’s management of Phase I won great respect for the project from the high-energy physics community and the Office of Project Assessment (OPA) at the DOE’s Office of Science. The OPA invited her to participate in a panel discussion to share her expertise and help develop project management guidelines that can be used in other Office of Science projects. Guo also worked with BNL’s Project Management Center to help the lab update its own project management system description to meet DOE standards and lay down valuable groundwork for future large projects.

    As the ATLAS Phase I upgrade proceeds through the final construction stage, Guo is simultaneously managing the planning stages of HL-LHC.

    “We haven’t completely defined the project timeline yet, but it’s projected to go all the way to the end of 2025,” Guo said.

    Like Phase I, HL-LHC will ensure ATLAS can perform well while the LHC operates at much higher collision rates so that physicists can further explore the Higgs as well as search for signs of dark matter and extra dimensions.

    Although she admits to missing doing research herself, Guo is not disheartened.

    “I’m still in the physics world; I’m still working with physicists,” she said. “I enjoy working and interacting with people. So I’m happy.”

    Brookhaven’s work on RHIC and ATLAS is funded by the DOE Office of Science.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 2:36 pm on February 10, 2017 Permalink | Reply
    Tags: , , BNL RHIC, , , Exploring the Matter that Filled the Early Universe, , , , Quark Matter 2017 conference (QM17), , Ultrarelativistic heavy-ion collisions   

    From BNL: “Exploring the Matter that Filled the Early Universe” 

    Brookhaven Lab

    February 6, 2017
    Karen McNulty Walsh
    kmcnulty@bnl.gov

    (631) 344-8350
    Peter Genzer
    (631) 344-3174
    genzer@bnl.gov

    1
    Credit for conference logo design: Anjali Chandrashekar, student, Pratt Institute

    Theorists and scientists conducting experiments that recreate matter as it existed in the very early universe are gathered in Chicago this week to present and discuss their latest results. These experiments, conducted at the world’s premier particle colliders — the Relativistic Heavy Ion Collider (RHIC) at the U.S. Department of Energy’s Brookhaven National Laboratory, and the Large Hadron Collider (LHC) at the European Center for Nuclear Research (CERN) — are revealing intriguing information about the building blocks of visible matter and the force that holds them together in the universe today.

    BNL RHIC Campus
    BNL/RHIC Star Detector
    RHIC map and STAR detector

    CERN/LHC Map
    CERN LHC Grand TunnelCERN LHC particles
    LHC at CERN

    The Quark Matter 2017 conference (QM17) will feature new results describing the particles created as atomic nuclei smash into one another at nearly the speed of light at RHIC and the LHC. These “ultrarelativistic heavy-ion collisions” melt ordinary protons and neutrons, momentarily setting free their inner constituents — quarks and gluons — so scientists can study their behavior and interactions. The physicists want to sort out the detailed properties of the hot “quark-gluon plasma” (QGP), and understand what happens as this primordial soup cools and coalesces to form the more familiar matter of today’s world.

    The two scientific collaborations conducting nuclear physics research at RHIC—STAR and PHENIX, named for their house-sized detectors—will present findings that build on earlier discoveries at this DOE Office of Science User Facility.

    Brookhaven Phenix
    Brookhaven Phenix

    The two collaborations perform cross-checking analyses to verify results, while also exploiting each detector’s unique capabilities and strengths for independent explorations. The QM17 presentations will showcase precision measurements made possible by recent detector upgrades.

    “These results illustrate how a global community of dedicated scientists is taking full advantage of RHIC’s remarkable versatility to explore in depth the structure of nuclear matter over a wide range of temperatures and densities to better understand the dynamic behavior of quarks and gluons and the strong nuclear force,” said Berndt Mueller, Associate Laboratory Director for Nuclear and Particle Physics at Brookhaven Lab. “The latest RHIC findings indicate that RHIC sits at the ‘sweet spot’ for probing the most interesting questions about the quark-gluon plasma and its transition to matter as we know it.”

    The meeting will also feature talks on the planned upgrade of the PHENIX experiment to a new RHIC detector known as sPHENIX, which will have greatly increased capabilities for tracking subatomic interactions.

    3
    The solenoid magnet that will form the core of the sPHENIX detector. No image credit

    In addition, at least one talk will focus on the scientific rationale for building an Electron-Ion Collider, a proposed future facility that would enable an in-depth exploration of gluons in protons and other nuclei, opening a new frontier in nuclear physics.

    In addition, at least one talk will focus on the scientific rationale for building an Electron-Ion Collider, a proposed future facility that would enable an in-depth exploration of gluons in protons and other nuclei, opening a new frontier in nuclear physics.

    Select QM 2017 Highlights from RHIC

    Does size really matter?

    Before RHIC began operations in 2000, nuclear physicists suspected it would take collisions of large nuclei such as gold to produce enough heat to create quark-gluon plasma. Since then, RHIC’s gold-gold smashups (and later collisions of lead nuclei at the LHC) have reliably recreated a soup of quarks and gluons that flows like a nearly “perfect” liquid with extraordinarily low viscosity. Scientists detect the flow by observing correlations in certain characteristics of particles streaming from the collisions even when they are relatively far apart. More recently, smashups of smaller nuclei such as helium and even single protons with the large nuclei have produced correlation patterns that suggest that smaller drops of QGP might be possible. The latest results, to be presented by PHENIX, come from collisions of protons with aluminum nuclei, and also from deuteron-gold collisions over a range of collision energies. Lowering the energy changes how long the QGP phase lasts, which should change the strength of the correlations. The new results also include the first analysis of particles emerging closest to the colliding beams in the forward and rearward directions, as tracked by the recently installed Forward Silicon Vertex Tracker. Adding this tracker to detector components picking up particles emerging more centrally, perpendicular to the colliding beams, gives the physicists a way to test in three dimensions how the correlations vary with the pressure gradients created by the asymmetrical collisions.

    Discerning differences among heavy quarks


    A virtual tour of the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC).

    PHENIX’s Central Barrel and Forward Silicon Vertex Tracker and STAR’s high precision Heavy Flavor Tracker (HFT) give RHIC physicists access to studying the behavior of so-called heavy quarks, which go by the exotic names of “charm” and “bottom.” These particles, produced in the QGP, start to decay into other particles a short distance from the collision zone, but those decay products eventually strike the trackers. By tracing their tracks, scientists can identify precisely where the decay took place. And since charm and bottom quarks have slightly different lifetimes before decaying, and therefore different travel distances, this method gives the scientists a way to tell them apart.

    Going with the flow

    One way scientists will use this data is to see how heavy quarks are affected by the QGP, and whether there are differences among them. Earlier indirect findings by PHENIX, later confirmed by STAR, already indicated that heavy quarks get swept up in the flow of the QGP, somewhat like a rock getting pulled along by a stream instead of sinking to the bottom. These observations formed part of the motivation for the construction of the STAR HFT. New data from the HFT to be presented by STAR provide the first direct evidence of heavy quark flow, and show that the interactions of these heavy particles with the QGP medium are strong. STAR’s HFT is the first application of the silicon based Monolithic Active Pixel Sensor technology in a collider environment. The measurements show that the flow of a type of heavy particles called D0s, which contain a charm quark, follows the same trend as seen for lighter particles and can be described by the same viscous hydrodynamics. The unprecedented precision in this measurement will pave the path towards precisely determining one of the intrinsic transport properties of the QGP and tell us how quarks interact with it.

    PHENIX will present precision results from its Central Barrel Vertex Detector showing that some heavy quarks are more affected by the QGP than others. The results show that charm quarks lose more energy in the QGP than heavier bottom quarks. With this high statistics data set, PHENIX will now be able to study how the energy-loss is affected by how central, or head-on, the collisions are. PHENIX will also present its first heavy-quark result from the Forward Silicon Vertex Tracker, measuring the total cross section of bottom quarks emerging in the forward and rearward directions in collisions between copper and gold ions.

    Learning how particles grow


    A virtual tour of the STAR detector at the Relativistic Heavy Ion Collider (RHIC).

    The STAR HFT has also made it possible to make the first measurements of a particle called Lambda c emerging from RHIC collisions. Lambda c is made of three quarks—just like protons and neutrons—but with one of the three being a heavy quark. These Lambda c particles are extremely difficult to tease out from the data. But because they can only be created in energetic particle collisions, they carry unique information about the conditions within. Studying this “sentry” information carried by the Lambda c should help scientists learn how relatively “free” quarks that populate the early-stage QGP eventually coalesce and combine to form the more familiar composite particles of ordinary matter.

    Tracking high-momentum jets

    Observing how jets of particles springing from individual quarks or gluons lose energy, or get “quenched,” as they interact with the medium has been one major sign that RHIC’s energetic collisions of gold on gold were forming QGP. STAR will present several new jet studies that provide further insights into both how this quenching occurs and how the lost energy re-emerges, In addition, PHENIX will present new results exploring the question of whether collisions of smaller particles with gold, which appear to create the flow patterns of QGP, also show evidence of jet quenching. Their results include data on jet energy loss in a variety of collision systems, both large and small. The method uses photons emitted opposite the jet to calibrate how much energy the jet should have to determine whether or not there was quenching. The data show some modifications to the jet structure and the yield of high-momentum particles inside the jets, but it is not yet clear how to interpret these results.

    Taking the QGP’s temperature

    Tracking heavy quarks and particles made from them gives RHIC physicists a new way to zero in on a more precise temperature of the QGP—already known to be more than 250,000 times hotter than the center of the sun. The new precision comes from measuring how different bound states of heavy quark-antiquark pairs, held together with different amounts of energy, melt in the plasma. STAR counts up different types of these particles (for example, Upsilons, pairs of bottom and anti-bottom quarks, that come in several binding varieties) using another recently upgraded detector component called the Muon Telescope Detector. Muons are the decay products of the Upsilons. STAR uses these counts to look for a deficit of one type of Upsilon relative to another to set boundaries on the QGP temperature. The physicists are eager to compare their results with those from the LHC, where with higher collision energies, they expect to see higher temperatures.

    PHENIX’s measurements of temperature have relied on tracking photons, particles of light, emitted from the hot matter (think of the glow of an iron bar in a blacksmith’s fire, where the color of the light is related to how hot the iron is). But PHENIX’s photon data have uncovered something unusual: While collisions initially emit photons equally in all directions, fractions of a second later the emitted photons appear to have a directional preference that resembles the elliptical flow pattern of the perfect liquid QGP. This is intriguing because photons shouldn’t interact with the matter—or even be produced in such measurable quantities as the matter produced in the collisions cools and expands. To explore this mystery, PHENIX measured thermal direct photons at different gold-gold collision energies (39, 62, and 200 billion electron volts, or GeV), as well as in the smaller collision system. The results they present will shed light on the sources of these direct photons.

    Disentangling the effects of cold nuclear matter

    RHIC physicists are also learning more about “cold” nuclear matter—the state of the nucleus, filled with a field of gluons, before it collides—and how to account for its effects when studying the hot QGP. In order to disentangle the effects of cold nuclear matter, PHENIX is comparing the suppression of the excited state of the bound charm-anti-charm particle known as Psi to its ground state. They are studying collisions of protons and helium with gold or aluminum—small systems where cold nuclear matter predominates—and will use these as a baseline for better understanding the sequential melting of the bound states in the hot QGP. Their findings indicate that the less tightly bound version of the Psi is more than twice as susceptible to the effects of cold nuclear matter than the more tightly bound version. This effect must be accounted for in analyzing the data from QGP-creating collisions where the presence of both cold and hot nuclear matter influences the results.

    New way to turn down the energy

    STAR has exploited RHIC’s ability to collide nuclei over a wide range of collision energies, conducting a Beam Energy Scan to explore the creation of QGP and its transition to ordinary nuclear matter over a wide range of conditions. At QM17 they’ll present data from collisions at the lowest energy yet. Instead of colliding one beam into the beam coming into the detector from the opposite direction, as occurs in most RHIC experiments, STAR placed a stationary target (a foil of gold) within the beam pipe inside STAR and aimed just one beam at the target. Like a collision in which one moving car crashes into one that is parked, this fixed-target collision lowered the impact compared to what would occur if both beams (or cars) were moving and colliding head on. Data from these low energy collisions will be an integral part of phase two of the Beam Energy Scan, which is enabled by improvements to the RHIC accelerator complex that allow for higher collision rates.

    Research at RHIC is funded primarily by the U.S. Department of Energy’s Office of Science and by these agencies and organizations.

    See the full article here .

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  • richardmitnick 12:59 pm on January 13, 2017 Permalink | Reply
    Tags: , BNL RHIC, , ,   

    From BNL: “sPHENIX Gets CD0 for Upgrade to Experiment Tracking the Building Blocks of Matter” 

    Brookhaven Lab

    January 13, 2017
    Karen McNulty Walsh
    kmcnulty@bnl.gov

    First step on a path toward a detector with unprecedented capabilities for deciphering how the properties of the hottest matter in the universe emerge from the interactions of its fundamental particles.

    [SEE? THE USA CAN STILL GET IT DONE IN HEP IF WE JUST MAKE THE RIGHT DECISIONS.]

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    The solenoid magnet that will form the core of the sPHENIX detector. No image credit.

    The U.S. Department of Energy (DOE) has granted “Critical Decision-Zero” (CD-0) status to the sPHENIX project, a transformation of one of the particle detectors at the Relativistic Heavy Ion Collider (RHIC)—a DOE Office of Science User Facility at Brookhaven National Laboratory—into a research tool with unprecedented precision for tracking subatomic interactions.

    BNL RHIC Campus
    BNL/RHIC
    RHIC a BNL, with map.

    This decision is an important first step in the DOE process for starting new projects, stating that there is a “mission need” for the capabilities described by the proposal.

    “We are very excited that the Department of Energy has recognized the importance of the sPHENIX project,” said Berndt Mueller, Associate Laboratory Director for Nuclear and Particle Physics at Brookhaven. “This upgrade will offer new insight into how the interactions of the smallest building blocks of matter give rise to the remarkable properties of ‘quark-gluon plasma’—a four-trillion-degree soup of fundamental particles that existed in the universe a microsecond after its birth and recreated regularly in particle collisions at RHIC.”

    As Brookhaven Lab physicist Dave Morrison, a co-spokesperson for the sPHENIX collaboration, explained, “sPHENIX will be an essential tool for exploring the quark-gluon plasma, including its ability to flow like a nearly ‘perfect’ liquid. The capabilities we develop and scientific insight we gain will also help us to prepare for the coming research directions in nuclear physics,” he said.

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    A schematic of the sPHENIX experiment at BNL. No image credit.

    The sPHENIX project is an upgrade of RHIC’s former PHENIX detector, which completed its data-taking mission in June 2016.

    “We’ll be leveraging scientific and financial investments already made when building RHIC,” said Gunther Roland, a physicist at the Massachusetts Institute of Technology and the other co-spokesperson for sPHENIX. “But at the same time, the transformation will introduce new, state-of-the-art detector systems.”

    With a superconducting solenoid magnet recycled from a physics experiment at DOE’s SLAC National Laboratory at its core, state-of-the-art particle-tracking detectors, and an array of novel high-acceptance calorimeters, sPHENIX will have the speed and precision needed to track and study the details of particle jets, heavy quarks, and rare, high-momentum particles produced in RHIC’s most energetic collisions. These capabilities will allow nuclear physicists to probe properties of the quark-gluon plasma at varying length scales to make connections between the interactions among individual quarks and gluons and the collective behavior of the liquid-like primordial plasma.

    Conceptual studies and R&D are already underway for key components, including the solenoid, calorimeters, and tracking detectors. The CD0 decision—the go-ahead that enables conceptual design and R&D to proceed—will enable these efforts and set sPHENIX on the path toward an exciting physics program starting in 2022.

    Research at RHIC and the sPHENIX project are supported primarily by the DOE Office of Science.

    See the full article here .

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  • richardmitnick 2:06 pm on January 6, 2017 Permalink | Reply
    Tags: BNL RHIC, ,   

    From BNL: “Theory Provides Roadmap in Quest for Quark Soup ‘Critical Point'” 

    Brookhaven Lab

    January 4, 2017
    Karen McNulty Walsh
    kmcnulty@bnl.gov

    Scientists seek to discover key point in transition from early universe soup of quarks and gluons to matter as we know it.

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    The nuclear theorists behind the new analysis: Swagato Mukherjee, Raju Venugopalan, and Yi Yin.

    Thanks to a new development in nuclear physics theory, scientists exploring expanding fireballs that mimic the early universe have new signs to look for as they map out the transition from primordial plasma to matter as we know it. The theory work, described in a paper recently published as an Editor’s Suggestion in Physical Review Letters (PRL), identifies key patterns that would be proof of the existence of a so-called “critical point” in the transition among different phases of nuclear matter. Like the freezing and boiling points that delineate various phases of water—liquid, solid ice, and steam—the points nuclear physicists seek to identify will help them understand fundamental properties of the fabric of our universe.

    Nuclear physicists create the fireballs by colliding ordinary nuclei—made of protons and neutrons—in an “atom smasher” called the Relativistic Heavy Ion Collider (RHIC), a U.S. Department of Energy Office of Science User Facility at Brookhaven National Laboratory.

    BNL RHIC Campus
    BNL/RHIC
    BNL/RHIC

    The subatomic smashups generate temperatures measuring trillions of degrees, hot enough to “melt” the protons and neutrons and release their inner building blocks—quarks and gluons. The collider essentially turns back the clock to recreate the “quark-gluon plasma” (QGP) that existed just after the Big Bang. By tracking the particles that emerge from the fireballs, scientists can learn about nuclear phase transitions—both the melting and how the quarks and gluons “freeze out” as they did at the dawn of time to form the visible matter of today’s world.

    “We want to understand the properties of QGP,” said nuclear theorist Raju Venugopalan, one of the authors on the new paper. “We don’t know how those properties might be used, but 100 years ago, we didn’t know how we’d use the collective properties of electrons, which now form the basis of almost all of our technologies. Back then, electrons were just as exotic as the quarks and gluons are now.”

    Changing phases

    RHIC physicists believe that two different types of phase changes can transform the hot QGP into ordinary protons and neutrons. Importantly, they suspect that the type of change depends on the collision energy, which determines the temperatures generated and how many particles get caught up in the fireball. This is similar to the way water’s freezing and boiling points can change under different conditions of temperature and the density of water molecules, Venugopalan explained.

    In low energy RHIC collisions, scientists suspect that while the change in phase from QGP to ordinary protons/neutrons occurs, both distinct states (QGP and ordinary nuclear matter) coexist—just like bubbles of steam and liquid water coexist at the same temperature in a pot of boiling water. It’s as if the quarks and gluons (or liquid water molecules) have to stop at that temperature and pay a toll before they can gain the energy needed to escape as QGP (or steam).

    In contrast, in higher energy collisions, there is no toll gate at the transition temperature where quarks and gluons must “stop.” Instead they move on a continuous path between the two phases.

    But what happens between these low-energy and high-energy realms? Figuring that out is now one of the major goals of what’s known as the “beam energy scan” at RHIC. By systematically colliding nuclei at a wide range of energies, physicists in RHIC’s STAR collaboration are searching for evidence of a special point on their map of these nuclear phases and the transitions between them—the nuclear phase diagram.

    At this so-called “critical point,” there would be a toll stop, but the cost would be $0, so the quarks and gluons could transition from protons and neutrons to QGP very quickly—almost as if all the water in the pot turned to steam in a single instant. This can actually happen when water reaches its boiling point under high pressure, where the distinction between the liquid and the compressed gas phases blurs to the point of the two being virtually indistinguishable. In the case of QGP, the physicists would expect to see signs of this dramatic effect—patterns in the fluctuations of particles observed striking their detectors—the closer and closer they get to this critical point.

    In experiments already conducted at the intermediate energies, STAR physicists have observed such patterns, which may be signs of the hypothesized critical point. This search will continue with increased precision over a wider range of energies during a second beam energy scan, beginning in 2019. The new theoretical work of Brookhaven physicist Swagato Mukherjee, Venugopalan, and former postdoc Yi Yin (now at MIT)—part of a newly funded Beam Energy Scan Theory (BEST) Topical Collaboration in Nuclear Theory—will provide a roadmap to guide the experimental researchers.

    2
    The STAR collaboration’s exploration of the “nuclear phase diagram” shows signs of a sharp border—a first-order phase transition—between the hadrons that make up ordinary atomic nuclei and the quark-gluon plasma (QGP) of the early universe when the QGP is produced at relatively low energies/temperatures. The data may also suggest a possible critical point, where the type of transition changes from the abrupt, first-order kind to a continuous crossover at higher energies.

    BNL/RHIC Star Detector
    BNL/RHIC Star Detector

    Signposts to look for

    Certain characteristics of the patterns that occur during phase changes are universal—no matter whether you are studying water, or quarks and gluons, or magnets. But one key advance of the new theory work was using a different set of universal characteristics to account for the dynamic conditions of the expanding quark-gluon plasma.

    “All the predictions, the way we started looking for a critical point so far, were based on patterns calculated assuming you have a pot boiling on a stove—a somewhat static system,” said Mukherjee. “But QGP is expanding and changing over time. It’s more like water boiling as it flows rapidly through a pipe.”

    To account for the evolving conditions of the QGP in their calculations, the theorists incorporated “dynamic universalities” that were first developed to describe similar pattern formation in the cosmological expansion of the universe itself.

    “These ideas have since been applied to other systems like liquid helium and liquid crystals,” Venugopalan said. “Yin realized that the specific mechanisms of dynamic universality identified in cosmology and condensed matter systems can be applied to the search for the critical point in heavy ion collisions. This paper is the first explicit demonstration of this conjecture.”

    Specifically, the paper predicts exactly what patterns to look for in the data—patterns in how the properties of particles emitted from the collisions are correlated—as the energy of the collisions changes.

    “If the STAR collaboration looks at the data in a particular way and sees these patterns, they can claim without any ambiguity that they have seen a critical point,” Venugopalan said.

    The Beam Energy Scan Theory Collaboration and research at RHIC are supported by the DOE Office of Science.

    Related Links

    Scientific paper: Universal Off-Equilibrium Scaling of Critical Cumulants in the QCD Phase Diagram

    See the full article here .

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  • richardmitnick 12:12 pm on August 3, 2016 Permalink | Reply
    Tags: , BNL RHIC, Scientists Model the 'Flicker' of Gluons in Subatomic Smashups   

    From BNL: “Scientists Model the ‘Flicker’ of Gluons in Subatomic Smashups” 

    Brookhaven Lab

    August 2, 2016
    Karen McNulty Walsh
    kmcnulty@bnl.gov
    (631) 344-8350
    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174

    Model identifies fluctuations in the glue-like particles that bind quarks within protons as essential to explaining experimental data on proton structure

    1
    Brookhaven Lab nuclear theorists Björn Schenke and Heikki Mäntysaari

    BNL RHIC Campus
    BNL RHIC Campus

    Scientists exploring the dynamic behavior of particles emerging from subatomic smashups at the Relativistic Heavy Ion Collider (RHIC)—a U.S. Department of Energy Office of Science User Facility for nuclear physics research at DOE’s Brookhaven National Laboratory—are increasingly interested in the role of gluons. These glue-like particles ordinarily bind quarks within protons and neutrons, and appear to play an outsized role in establishing key particle properties.

    A new study just published in Physical Review Letters reveals that a high degree of gluon fluctuation—a kind of flickering rearrangement in the distribution of gluon density within individual protons—could help explain some of the remarkable results at RHIC and also in nuclear physics experiments at the Large Hadron Collider (LHC) in Europe.

    Right now it’s impossible to directly “see” the distribution of gluons within individual protons and nuclei—even at the most powerful particle accelerators. So Brookhaven Lab theoretical physicists Björn Schenke and Heikki Mäntysaari developed a mathematical model to represent a variety of arrangements of gluons within a proton.

    “It is very accurately known how large the average gluon density is inside a proton,” Mäntysaari said. “What is not known is exactly where the gluons are located inside the proton. We model the gluons as located around the three valance quarks. Then we control the amount of fluctuations represented in the model by setting how large the gluon clouds are, and how far apart they are from each other.”

    The fluctuations represent the behavior of gluons in particles accelerated to high energies as they are in colliders like RHIC and the LHC. Under those conditions, the gluons are virtual particles that continuously split and recombine, essentially flickering in and out of existence like fireflies blinking on and off in the nighttime sky.

    Scientists would like to know if and how these fluctuations affect the behavior of the particles created when protons collide with heavy nuclei, like the gold ions accelerated at RHIC. Data from RHIC’s proton-gold collisions, and from the LHC’s proton-lead collisions, have shown evidence of “collective phenomena”—particles emerging with some “knowledge” of one another and in some preferred directions rather than in a uniform fashion. In RHIC and LHC smashups of two large particles (gold-gold or lead-lead), this collective behavior and direction-dependent flow has been explained by the liquid state of quarks and gluons—the “perfect liquid” quark-gluon plasma (QGP)—created in these collisions. But collisions of tiny protons with the larger nuclei aren’t supposed to create QGP. And the current understanding of the QGP can’t completely explain the experimental results.

    “If we want to understand what happens, we have to know the geometry of the proton just before the collisions. It makes a difference if you have a round object hitting a nucleus vs. something with a more irregular structure hitting the nucleus,” Mäntysaari said. “The collective behavior we see in the experiments might imply that there is some more complex structure to the proton,” he added, noting that exploring the internal structure of the proton is a fundamental research endeavor for nuclear physicists.

    The model developed by Mäntysaari and Schenke describes how the proton structure can fluctuate. To test the model, they turned to a different set of experimental data—results from collisions of electrons with protons at the HERA accelerator in Germany.

    4
    HERA at DESY

    6
    DESY campus

    A particular reaction that sometimes occurs in these collisions—where a particle called a J/psi is produced and the proton breaks up into a spray of other particles—is highly dependent on the level of structural fluctuations in the proton.

    The Brookhaven theorists used their model to predict the frequency of this interaction while varying the level of gluon fluctuations, and compared their calculations with the experimentally observed data. They found that the version of their model with the highest degree of fluctuations was the one that fit the data best.

    3
    Four snapshots of the gluon density in a proton at high energy, as modeled by Mäntysaari and Schenke. Red indicates high gluon density, blue indicates low density.

    “This process doesn’t happen at all if the proton always looks the same. The more fluctuations we have, the more likely this process is to happen,” Mäntysaari said.

    He and Schenke are now looking to apply this knowledge to the proton-nucleus collisions.

    “When the gluon fluctuations are incorporated into the hydrodynamic models of QGP, we get a better agreement with the experimental data from these proton-nucleus collisions,” Mäntysaari said.

    As Schenke noted, “This implies that the formation of a strongly interacting QGP in proton-nucleus collisions provides a possible explanation of the experimentally observed collectivity.”

    If the nuclear physics community gets to build a proposed future project called an Electron-Ion Collider (EIC), they’ll have an opportunity to improve on the precision of these results.

    “An EIC will allow us to measure this more precisely, and in different kinematics—how the fluctuations depend on energy, for example,” Mäntysaari said. “And an EIC can also do the same kind of studies in nuclear targets to see how much the structure of the nucleus fluctuates event by event.”

    In essence, the EIC would be a true gluon-imaging machine—a way to directly probe the internal structure of the building blocks of visible matter, including the glue that binds everything in the universe today.

    This research was funded by the DOE Office of Science.

    See the full article here .

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    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 3:51 pm on June 23, 2016 Permalink | Reply
    Tags: BNL RHIC, , , ,   

    From DEIXIS via ORNL: “Early-universe soup” 

    i1

    Oak Ridge National Laboratory

    DEIXIS

    June 22nd, 2016
    Sarah Webb

    ORNL’s Titan supercomputer is helping Brookhaven physicists understand the matter that formed microseconds after the Big Bang.

    ORNL Titan Supercomputer
    ORNL Crfay Titan Supercomputer

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    An experimental and theoretical exploration of the quantum chromodynamics (QCD) phase diagram. The matter produced in collisions at the highest energies and the smallest baryon chemical potentials can change from quark-gluon plasma (QGP) to a hadron gas through a smooth crossover. But lower energy collisions can access higher baryon chemical potentials where a first-order phase transition line is thought to exist. The reach of the future DOE Basic Energy Sciences program at RHIC is shown, as are the trajectories on the phase diagram followed by the cooling droplets of QGP produced in collisions with varying energy. The present reach of lattice QCD calculations is illustrated by the yellow band. (Illustration: Swagato Mukherjee, Brookhaven National Laboratory.)

    At the dawn of the universe – just after the Big Bang – all matter was in the form of a hot-flowing soup called quark-gluon plasma, or QGP. Though a few ambitious, atom-smashing experiments have produced transient samples of this extreme phase of matter, researchers still have much to learn about its fundamental behavior.

    Experimental physicists have tried to produce quark-gluon plasma since the 1980s and first reported observing it in 2000. Over the past 45 years, theorists have outlined the equations that govern QGP and many have combined theory and experiment to describe it.

    Large-scale computations have been critical to the theoretical study of QGP’s novel characteristics. As part of a theoretical effort funded by the Department of Energy, Brookhaven National Laboratory’s Swagato Mukherjee and his colleagues are using an allotment of 167 million processor hours from the ASCR Leadership Computing Challenge (ALCC) to better understand QGP. Their findings will help physicists plan the next wave of experiments. “Neither theory nor experiment can do this alone,” Mukherjee says.

    At the heart of every atom lies the nucleus, a super-tight ball of subatomic protons and neutrons. Those particles are made of even smaller parts, including quarks, which comprise just one thousandth of the mass. Gluons, the adhesive particles that hold quarks together, carry the strong interaction, a fundamental physical force that binds the atomic nucleus and generates the other 99.9 percent of all matter’s mass.

    But at temperature extremes 70,000 times hotter than the center of the sun, even tightly packed quarks and gluons begin to flow. The transition to the flowing state is much like phase changes in matter such as water. Water exists as liquid, steam or ice, based on how much heat and pressure are applied. Scientists long ago carefully mapped the underlying conditions and boundaries between water’s different forms as a phase diagram, information that’s been critical for understanding water’s behavior. If researchers can understand how changes in temperature and density affect QGP, physicists can create a similar roadmap documenting conditions that form it.

    Because of the extreme conditions required for QGP creation, the only way to observe it on Earth is to bombard matter with high-energy particles at either the Relativistic Heavy Ion Collider (RHIC) at Brookhaven or the Large Hadron Collider at CERN in Switzerland.

    BNL/RHIC
    BNL/RHIC

    CERN LHC Grand Tunnel
    CERN/LHC

    Fast-moving nuclei of lead and gold collide at high energy, briefly producing the plasma-soup researchers can study.

    Experiments aren’t the only way to study QGP’s properties. Physicists have worked out the theory of how quarks and gluons interact, known as quantum chromodynamics, or QCD. However, the complexity of these interactions, with billions of variables, requires sophisticated parallel computing resources to solve, Mukherjee says.

    Using their ALCC allotment, Mukherjee and his colleagues have concentrated on a version of this theory, lattice QCD, to computationally study the plasma on Titan, a Cray XK7 at Oak Ridge National Laboratory. The calculations line up quarks at the intersection points on a grid, with gluons positioned on each of the crossbars between them. Initially, the researchers omitted the density component and solely calculated how increasing heat eventually produces the flowing QGP. Now they’ll need to consider the density component as well. With their ongoing ALCC allotment, they’re simulating how increasing density changes the phase diagram and eventually the plasma’s behavior.

    These types of computations will be critical for future experiments at the big colliders. In 2019 and 2020, DOE will support a large collaborative effort, the Beam Energy Scan II at RHIC, to observe the full phase diagram of quark-gluon plasma, including the density component, Mukherjee says, an effort that will cost hundreds of millions of dollars. The calculations Mukherjee and his colleagues perform will provide information that helps the experimental physicists plan those experiments. The calculations will provide temperature benchmarks – a range needed to generate QGP.

    In large particle accelerators, researchers can’t control the temperature or density, only the energy of the atomic collisions, Mukherjee says. So calculations will help researchers translate that collision energy into the heat and density parameters they need to observe the full range of changes in the phase diagram of quark-gluon plasma.

    Ultimately, the exercise is about fundamental discovery and collaboration between theorists and experimentalists to discover the quark-gluon soup recipe. Mukherjee is part of a larger Brookhaven theoretical team, the Nuclear Physics Lattice Gauge Theory group led by Fritjof Karsch. This work is an integral part of the BEST collaboration – for Beam Energy Scan Theory – a DOE-funded, multi-institutional Topical Collaboration in Nuclear Theory, looking at the phases and properties of hot-dense QCD matter. Mukherjee’s research is supported by DOE Office of Science’s Nuclear Physics program.

    See the full article here .

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  • richardmitnick 12:27 pm on March 29, 2016 Permalink | Reply
    Tags: A View of the Colorful Microcosm Within a Proton, , BNL RHIC, ,   

    From BNL: “A View of the Colorful Microcosm Within a Proton” 

    Brookhaven Lab

    March 28, 2016
    Karen McNulty Walsh, (631) 344-8350
    kmcnulty@bnl.gov

    Peter Genzer, (631) 344-3174
    genzer@bnl.gov

    Probing the “color” interactions among quarks tests a theoretical concept of nature’s strongest force to pave a way toward mapping protons’ 3D internal structure

    1
    Brookhaven physicist Elke Aschenauer, a member of the STAR collaboration.

    The proton sounds like a simple object, but it’s not.

    The quark structure of the proton 16 March 2006 Arpad Horvath
    The quark structure of the proton 16 March 2006 Arpad Horvath

    Inside, there’s a teeming microcosm of quarks and gluons with properties such as spin and color charge that contribute to the particle’s seemingly simplistic role as a building block of visible matter. By analyzing the particle debris emitted from collisions of polarized protons at the Relativistic Heavy Ion Collider (RHIC), scientists say they’ve found a new way to glimpse that internal microcosm. They’ve measured a key effect of the so-called color interaction—the basis for the strong [interaction] that binds quarks within the proton. This new measurement tests, for the first time, theoretical concepts that are essential for mapping the proton’s three-dimensional internal structure.

    The research, described in a paper to be published as an Editor’s Suggestion in Physical Review Letters, is only possible at RHIC, a 2.4-mile circular particle collider that operates as a U.S. Department of Energy (DOE) Office of Science User Facility for nuclear physics research at DOE’s Brookhaven National Laboratory. RHIC is unique in that it uses specialized magnets to strategically align the spins of billions of tiny protons so they are mostly pointing in a particular direction as they circulate and collide.

    This adjustable polarization is essential for teasing out details of the particles’ internal structure, including how their constituent quarks and glue-like binding particles called gluons contribute to the protons’ overall spin, and how these particles interact.

    “In this experiment, the polarization gives scientists a unique way to understand hard-to-catch details of how the ‘color’ charges of quarks and gluons affect their microcosmic interactions,” explained Brookhaven physicist Elke Aschenauer, a member of the scientific collaboration using RHIC’s STAR detector to analyze the subatomic smashups.

    Colors seen and unseen

    If you’ve ever seen the colorful images of particle tracks emerging from collisions at STAR, you might wonder what all the fuss over “color” is about. STAR has been producing these firework-like displays since RHIC started operating in June 2000. The colors of those tracks help identify the types of particles emerging from RHIC collisions. But the “color” of the quarks that make up the colliding ions is a rather different concept. It’s a type of charge that borrows a naming convention from our understanding of visible light because it comes in three forms that must be combined to form a neutral state—similar to the way the three primary colors of light (red, green, and blue) combine to form “neutral” white light.

    2
    RHIC physicists used collisions of protons with their spins aligned transverse (perpendicular) to their direction of motion (left) with an unpolarized proton beam (right) to search for the effects of the interaction between “like” color charges. They were looking for a lopsided production of particles called W bosons, but in the opposite direction to that observed by experiments measuring the effects of “unlike” color interactions. The scientists can’t measure W particles directly because they decay quickly, in the case shown, into an electron (e) and a neutrino (ν)—another notoriously difficult-to-detect particle. Instead they track a jet of particles that recoil in the opposite direction as the neutrino disappears, and add their energy to the energy of the electron to reconstruct each W. So far these experiments at RHIC’s STAR detector reveal a hint of this effect of the repulsive color interaction—a hint physicists hope to nail with future experiments.

    As is the case with more-familiar positive and negative electric charges, in color charge, opposites attract and like charges repel.

    “To get neutral (white) you need all three colors. So the opposite of each individual color charge is the other two combined,” Aschenauer said.

    The need for three differently colored quarks to combine is the defining property of the strong nuclear force—which makes it impossible for quarks to be free, and ultimately binds protons and neutrons to form the atoms of visible matter. While several experiments have sought to measure the effects of the attractive interaction that binds “unlike” color charges, scientists have now, for the first time, measured an effect of the repulsive color interaction when “like” color charges meet up in particle collisions at RHIC.

    Same asymmetry, opposite sign

    3
    Brookhaven Lab/STAR physicist Salvatore Fazio, who led the analysis of these results

    Probing the effects of color charge interactions in particle collisions at STAR is no easy task. As STAR collaborator Salvatore Fazio explained, the RHIC physicists do it by measuring the number, trajectory, and energy level of particles called W bosons that emerge from RHIC’s collisions of polarized protons. But Ws decay in a flash—into an electron, which is fairly easy to pick up, and a neutrino, a notoriously elusive particle that quickly escapes. To get a read on the neutrino’s energy, the scientists must detect all the particles that recoil in the opposite direction from the escaping neutrino—then add all that together with the energy of the electron to get the information they need about each W.

    This reconstruction of a particle from a jet-like spray of debris requires a big detector with a very large acceptance—the ability to track a wide variety of particles over a very large area. In other words, you need STAR, a tracking detector that, like a giant barrel, covers the region around the point where the beams collide and is capable of catching thousands of particle sprays per second.

    “The details about this measurement are very technical,” Fazio said, “but counting up all the Ws can point to something called a ‘single transverse spin asymmetry’—an imbalance in the number of these particles emerging to one side of the detector compared to the other depending on where the spin of the proton is pointing.” This measurement is a big step toward verifying a long-standing theoretical prediction based on insights into the workings of the color interaction.

    As Aschenauer pointed out, “There are a lot of initiatives in the world to measure this asymmetry in electron- or muon-proton collisions, using fixed targets at other facilities such as COMPASS, HERMES, and Thomas Jefferson National Accelerator Facility.

    CERN/COMPASS
    CERN/COMPASS

    DESY HERMES
    DESY/HERMES

    JLab campus
    JLab

    But all the measurements from those experiments reflect the effects of the attractive force between ‘unlike’ color charges. The only way to test the theory of the color interaction being in one case attractive and in the other repulsive is to have an observable that is driven by the repulsive interaction between ‘like’ color charges—which is what we were able to test with polarized proton-proton collisions at RHIC.”

    BNL/RHIC Star
    BNL/RHIC Star Detector

    The hypothesis was that the RHIC experiment would produce the same spatial imbalance in W production, but in the opposite direction as seen in the experiments sensitive to the interactions of “unlike” color charges. The experimental test of this “sign change” is one of the open questions in hadronic physics and was recently noted as a priority by the nation’s Nuclear Science Advisory Committee (NSAC).

    Even after conducting these studies for a relatively short time as a way to prove the concept, the STAR team says they’ve seen a hint of the sign change, but more data are needed to be sure.

    “Because it is such a complicated measurement, we initially did not dedicate an entire run to this. But now we do have a hint we want to pursue,” Fazio said. The team hopes to nail the case in the RHIC run of 2017, which for STAR, will be dedicated to this measurement.

    In addition, because these new findings align with the theory scientists have been using to describe the inner structure of the proton, they also support their plan to use future collisions of electrons with polarized protons at a proposed electron ion collider (EIC) to conduct detailed studies of the internal structure of the proton.

    “These STAR measurements give an indication of the internal momentum of quarks and gluons, both in the direction of motion but also transverse momentum. An EIC would unravel all the necessary details to produce 3D pictures of the proton’s momentum structure,” Aschenauer said.

    STAR Collaboration: L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, A. Aparin, D. Arkhipkin, E. C. Aschenauer, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Banerjee, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, I. Bunzarov, J. Butterworth, H. Caines, M. Calderón de la Barca Sánchez, J. M. Campbell, D. Cebra, I. Chakaberia, P. Chaloupka, Z. Chang, S. Chattopadhyay, J. H. Chen, X. Chen, J. Cheng, M. Cherney, W. Christie, G. Contin, H. J. Crawford, S. Das, L. C. De Silva, R. R. Debbe, T. G. Dedovich, J. Deng, A. A. Derevschikov, B. di Ruzza, L. Didenko, C. Dilks, X. Dong, J. L. Drachenberg, J. E. Draper, C. M. Du, L. E. Dunkelberger, et al. (280 additional authors not shown) [Institutions not named.]

    Research at RHIC is supported primarily by the DOE Office of Science.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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