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  • richardmitnick 8:46 am on September 4, 2015 Permalink | Reply
    Tags: Accelerator Science, , BNL PHENIX, , ,   

    From BNL: “Tiny Drops of Early Universe ‘Perfect’ Fluid” 

    Brookhaven Lab

    August 31, 2015
    Karen McNulty Walsh, (631) 344-8350 or Peter Genzer, (631) 344-3174

    1
    The upper panel of this image represents initial hot spots created by collisions of one, two, and three-particle ions with heavy nuclei. The lower panel shows the geometrical patterns of particle flow that would be expected if the small-particle collisions are creating tiny hot spots of quark-gluon plasma.

    The Relativistic Heavy Ion Collider (RHIC), a particle collider for nuclear physics research at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, smashes large nuclei together at close to the speed of light to recreate the primordial soup of fundamental particles that existed in the very early universe.

    BNL RHIC Campus
    BNL RHIC

    RHIC

    Experiments at RHIC—a DOE Office of Science User Facility that attracts more than 1,000 collaborators from around the world—have shown that this primordial soup, known as quark-gluon plasma (QGP), flows like a nearly friction free “perfect” liquid. New RHIC data just accepted for publication in the journal Physical Review Letters now confirm earlier suspicions that collisions of much smaller particles can also create droplets of this free-flowing primordial soup, albeit on a much smaller scale, when they collide with the large nuclei.

    “These tiny droplets of quark-gluon plasma were at first an intriguing surprise,” said Berndt Mueller, Associate Laboratory Director for Nuclear and Particle Physics at Brookhaven. “Physicists initially thought that only the nuclei of large atoms such as gold would have enough matter and energy to set free the quark and gluon building blocks that make up protons and neutrons. But the flow patterns detected by RHIC’s PHENIX collaboration in collisions of helium-3 nuclei with gold ions now confirm that these smaller particles are creating tiny samples of perfect liquid QGP.”

    These results build on earlier findings from collisions of two-particle ions known as deuterons with gold ions at RHIC, as well as proton-lead and proton-proton collisions at Europe’s Large Hadron Collider (LHC).

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    They also set the stage for the current run colliding protons with gold at RHIC.

    “The idea that collisions of small particles with larger nuclei might create minute droplets of primordial quark-gluon plasma has guided a series of experiments to test this idea and alternative explanations, and stimulated a rich debate about the implications of these findings,” said University of Colorado physicist Jamie Nagle, a co-spokesperson of the PHENIX collaboration at RHIC. “These experiments are revealing the key elements required for creating quark-gluon plasma and could also offer insight into the initial state characteristics of the colliding particles.”

    Geometrical flow patterns

    2
    Relativistic Heavy Ion Collider’s PHENIX detector

    The discovery of the “perfect” liquid at RHIC, announced definitively in 2005, was largely based on observations of particles flowing in an elliptical pattern from the matter created in RHIC’s most energetic gold-gold collisions. This flow was a clear sign that particles emerging from the collisions were behaving in a correlated, or collective, way that contrasted dramatically with the uniformly expanding gas the scientists had expected. Additional experiments confirmed that this liquid is indeed composed of visible matter’s most fundamental building blocks, quarks and gluons, no longer confined within individual protons and neutrons, and that the flow occurs with minimal resistance—making it a nearly “perfect” liquid QGP.

    “Experiments colliding smaller particles with the heavy ions were originally designed as control experiments because they weren’t supposed to create the QGP,” Nagle said. “But observations at the LHC of very energetic proton-proton collisions and later experiments there colliding protons with lead revealed hints that particles streaming from those tiny collisions were also behaving collectively and flowing. It looked a lot like some of the perfect liquid signatures originally discovered in gold-gold collisions at RHIC, and later in lead-lead collisions at the LHC.”

    When RHIC physicists checked data from the RHIC run of 2008, when deuterons (a nucleus made of one proton and one neutron) were smashed into gold ions, they saw a similar pattern.

    “Since the deuteron is two particles, it creates two separate impacts on the nucleus—two hot spots that appear to merge and form an elongated drop of QGP,” Nagle said.

    Definitive tests

    Those observations triggered the idea of testing for flow patterns in a range of more tightly controlled experiments, which is only possible at RHIC, where physicists can collide a wide variety of ions to control the shape of the droplets of matter created. With additional deuteron-gold collisions already in hand, the RHIC scientists set out to collide three-particle helium-3 nuclei (each made of two protons and one neutron) with gold—and later, single protons with gold.

    “The PHENIX detector can pick up particles coming out of collisions very far forward and backward from the collision point. This large angle coverage allows us to measure the flow in these small collision systems,” said Shengli Huang, a PHENIX collaborator from Vanderbilt University who carried out the analysis. “PHENIX also has a trigger detector that picks up and records the most violent collisions—the ones in which the flow pattern is most apparent,” he said.

    The analysis of those events, as described in the new paper, reveals that the helium-gold collisions exhibit a triangular pattern of flow that the scientists say is consistent with the creation of three tiny droplets of QGP. They also say the data indicate that these small particle collisions could be producing the extreme temperatures required to free quarks and gluons—albeit at a much smaller, more localized scale than in the relatively big domains of QGP created in collisions of two heavy ions.

    “This is a pretty definitive measurement,” Nagle said. “The paper has a plot of elliptical and triangular flow that pretty much matches the hydrodynamic flow calculations we’d expect for QGP. We are really engineering different shapes of the QGP to manipulate it and see how it behaves.”

    There are other key signatures of QGP formation, such as the stopping of energetic particle jets, which have not been detected in the tiny droplets. And other theoretical explanations suggest the flow patterns resulting from some of the small particle-nucleus collisions could emerge from the interactions of gluons within the colliding particles, rather than from the formation of QGP.

    “At this time, the only theoretical framework that reproduces the patterns we’re observing in deuteron-gold and helium-3-gold collisions is fluid dynamics,” said Bjoern Schenke, a nuclear theorist at Brookhaven Lab. “It remains to be seen if alternative models can describe these patterns as well.”

    If other models also turn out to be compatible with the helium-3-gold data, physicists will want to explore whether these models make predictions that differ from those of the hydrodynamic flow model, and for which types of collisions.

    “The good news is that RHIC, with its unrivaled versatility, will likely be able to study any system that can discriminate between different models,” Mueller said.

    Research at RHIC is funded primarily by the DOE Office of Science and also by these agencies and organizations.

    See the full article here.

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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.
    i1

     
  • richardmitnick 1:26 pm on September 1, 2015 Permalink | Reply
    Tags: Accelerator Science, , , , ,   

    From CERN: “ATLAS and CMS experiments shed light on Higgs properties” 

    CERN New Masthead

    01 Sep 2015
    No Writer Credit

    1
    Results of the analyses by individual experiments (coloured) and both experiments together (black), showing the improvement in precision resulting from the combination of results.

    Three years after the announcement of the discovery of a new particle, the so-called Higgs boson, the ATLAS and CMS Collaborations present for the first time combined measurements of many of its properties, at the third annual Large Hadron Collider Physics Conference (LHCP 2015). By combining their analyses of the data collected in 2011 and 2012, ATLAS and CMS draw the sharpest picture yet of this novel boson. The new results provide in particular the best precision on its production and decay and on how it interacts with other particles. All of the measured properties are in agreement with the predictions of the Standard Model and will become the reference for new analyses in the coming months, enabling the search for new physics phenomena. This follows the best measurement of the mass of the Higgs boson, published in May 2015 (link is external) after a combined analysis by the two collaborations.

    “The Higgs boson is a fantastic new tool to test the Standard Model of particle physics and study the Brout-Englert-Higgs mechanism that gives mass to elementary particles,” said CERN* Director General Rolf Heuer.

    1
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    “There is much benefit in combining the results of large experiments to reach the high precision needed for the next breakthrough in our field. By doing so, we achieve what for a single experiment would have meant running for at least 2 more years.”

    There are different ways to produce a Higgs boson, and different ways for a Higgs boson to decay to other particles. For example, according to the Standard Model, the theory that describes best forces and particles, when a Higgs boson is produced, it should decay immediately in about 58% of cases into a bottom quark and a bottom antiquark. By combining their results, ATLAS and CMS determined with the best precision to date the rates of the most common decays.

    Such precision measurements of decay rates are crucially important as they are directly linked to the strength of the interaction of the Higgs particle with other elementary particles, as well as to their masses. Therefore, the study of its decays is essential in determining the nature of the discovered boson. Any deviation in the measured rates compared to those predicted by the Standard Model would bring into question the Brout-Englert-Higgs mechanism and possibly open the door to new physics beyond the Standard Model.

    “This is a big step forward, both for the mechanics of the combinations and in our measurement precision, ” said ATLAS Spokesperson Dave Charlton. “As an example, from the combined results the decay of the Higgs boson to tau particles is now observed with more than 5 sigma significance, which was not possible from CMS or ATLAS alone.”

    “Combining results from two large experiments was a real challenge as such analysis involves over 4200 parameters that represent systematic uncertainties,” said CMS Spokesperson Tiziano Camporesi. “With such a result and the flow of new data at the new energy level at the LHC, we are in a good position to look at the Higgs boson from every possible angle”.

    • CERN, the European Organization for Nuclear Research, is the world’s leading laboratory for particle physics. It has its headquarters in Geneva. At present, its member states are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a Candidate for Accession. Serbia is an Associate Member in the pre-stage to Membership. Pakistan and Turkey are Associate Members. India, Japan, the Russian Federation, the United States of America, the European Union, JINR and UNESCO have observer status.

    See the full article here.

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    Meet CERN in a variety of places:

    Cern Courier

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New
    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New

    LHC

    CERN LHC New
    CERN LHC Grand Tunnel

    LHC particles

    Quantum Diaries

     
  • richardmitnick 11:53 am on August 27, 2015 Permalink | Reply
    Tags: Accelerator Science, , , , , ,   

    From U Maryland: “Evidence Suggests Subatomic Particles Could Defy the Standard Model” 

    U Maryland bloc

    University of Maryland

    August 26, 2015
    Matthew Wright
    301-405-9267
    mewright@umd.edu

    Large Hadron Collider team finds hints of leptons acting out against time-tested predictions

    The Standard Model of particle physics, which explains most of the known behaviors and interactions of fundamental subatomic particles, has held up remarkably well over several decades.

    2
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    This far-reaching theory does have a few shortcomings, however—most notably that it doesn’t account for gravity. In hopes of revealing new, non-standard particles and forces, physicists have been on the hunt for conditions and behaviors that directly violate the Standard Model.

    Now, a team of physicists working at CERN’s Large Hadron Collider (LHC) has found new hints of particles—leptons, to be more precise—being treated in strange ways not predicted by the Standard Model. The discovery, scheduled for publication in the September 4, 2015 issue of the journal Physical Review Letters, could prove to be a significant lead in the search for non-standard phenomena.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    1
    In this event display from the LHCb experiment at CERN’s Large Hadron Collider, proton-proton collisions at the interaction point (far left) result in a shower of leptons and other charged particles. The yellow and green lines are computer-generated reconstructions of the particles’ trajectories through the layers of the LHCb detector. Image credit: CERN/LHCb Collaboration

    3
    LHCb Detector

    The team, which includes physicists from the University of Maryland who made key contributions to the study, analyzed data collected by the LHCb detector during the first run of the LHC in 2011-12. The researchers looked at B meson decays, processes that produce lighter particles, including two types of leptons: the tau lepton and the muon. Unlike their stable lepton cousin, the electron, tau leptons and muons are highly unstable and quickly decay within a fraction of a second.

    According to a Standard Model concept called “lepton universality,” which assumes that leptons are treated equally by all fundamental forces, the decay to the tau lepton and the muon should both happen at the same rate, once corrected for their mass difference. However, the team found a small, but notable, difference in the predicted rates of decay, suggesting that as-yet undiscovered forces or particles could be interfering in the process.

    “The Standard Model says the world interacts with all leptons in the same way. There is a democracy there. But there is no guarantee that this will hold true if we discover new particles or new forces,” said study co-author and UMD team lead Hassan Jawahery, Distinguished University Professor of Physics and Gus T. Zorn Professor at UMD. “Lepton universality is truly enshrined in the Standard Model. If this universality is broken, we can say that we’ve found evidence for non-standard physics.”

    The LHCb result adds to a previous lepton decay finding, from the BaBar experiment at the Stanford Linear Accelerator Center, which suggested a similar deviation from Standard Model predictions.

    SLAC Babar
    SLAC/BaBaR

    (The UMD team has participated in the BaBar experiment since its inception in 1990’s.) While both experiments involved the decay of B mesons, electron collisions drove the BaBar experiment and higher-energy proton collisions drove the LHC experiment.

    “The experiments were done in totally different environments, but they reflect the same physical model. This replication provides an important independent check on the observations,” explained study co-author Brian Hamilton, a physics research associate at UMD. “The added weight of two experiments is the key here. This suggests that it’s not just an instrumental effect—it’s pointing to real physics.”

    “While these two results taken together are very promising, the observed phenomena won’t be considered a true violation of the Standard Model without further experiments to verify our observations,” said co-author Gregory Ciezarek, a physicist at the Dutch National Institute for Subatomic Physics (NIKHEF).

    “We are planning a range of other measurements. The LHCb experiment is taking more data during the second run right now. We are working on upgrades to the LHCb detector within the next few years,” Jawahery said. “If this phenomenon is corroborated, we will have decades of work ahead. It could point theoretical physicists toward new ways to look at standard and non-standard physics.”

    With the discovery of the Higgs boson—the last major missing piece of the Standard Model—during the first LHC run, physicists are now looking for phenomena that do not conform to Standard Model predictions.

    Higgs Boson Event
    Higgs Boson event at CMS

    CERN CMS Detector
    CMS Detector in the LHC at CERN

    Jawahery and his colleagues are excited for the future, as the field moves into unknown territory.

    “Any knowledge from here on helps us learn more about how the universe evolved to this point. For example, we know that dark matter and dark energy exist, but we don’t yet know what they are or how to explain them. Our result could be a part of that puzzle,” Jawahery said. “If we can demonstrate that there are missing particles and interactions beyond the Standard Model, it could help complete the picture.”

    ###

    In addition to Jawahery and Hamilton, UMD Graduate Assistants Jason Andrews and Jack Wimberley are co-authors on the paper. The UMD LHCb team also includes Research Associate William Parker and Engineer Thomas O’Bannon, who are not coauthors on the paper.

    The research paper, “Measurement of the ratio of branching fractions…,” The LHCb Collaboration, is scheduled to appear online August 31, 2015 and to be published September 4, 2015 in the journal Physical Review Letters.

    See the full article here.

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    U Maryland Campus

    Driven by the pursuit of excellence, the University of Maryland has enjoyed a remarkable rise in accomplishment and reputation over the past two decades. By any measure, Maryland is now one of the nation’s preeminent public research universities and on a path to become one of the world’s best. To fulfill this promise, we must capitalize on our momentum, fully exploit our competitive advantages, and pursue ambitious goals with great discipline and entrepreneurial spirit. This promise is within reach. This strategic plan is our working agenda.

    The plan is comprehensive, bold, and action oriented. It sets forth a vision of the University as an institution unmatched in its capacity to attract talent, address the most important issues of our time, and produce the leaders of tomorrow. The plan will guide the investment of our human and material resources as we strengthen our undergraduate and graduate programs and expand research, outreach and partnerships, become a truly international center, and enhance our surrounding community.

    Our success will benefit Maryland in the near and long term, strengthen the State’s competitive capacity in a challenging and changing environment and enrich the economic, social and cultural life of the region. We will be a catalyst for progress, the State’s most valuable asset, and an indispensable contributor to the nation’s well-being. Achieving the goals of Transforming Maryland requires broad-based and sustained support from our extended community. We ask our stakeholders to join with us to make the University an institution of world-class quality with world-wide reach and unparalleled impact as it serves the people and the state of Maryland.

     
  • richardmitnick 9:37 am on August 27, 2015 Permalink | Reply
    Tags: Accelerator Science, , , ,   

    From FNAL- “Frontier Science Result: CDF Never alone” 

    FNAL II photo

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Aug. 27, 2015
    Matthew Jones

    2

    1
    The top plot shows the fraction of charged particles produced around a Ds+ meson that are kaons as a function of the particle transverse momentum. The bottom plot shows the fraction produced around a D+ meson. A larger kaon fraction is observed in association with Ds+ production because the kaon contains the strange quark produced in association with the antistrange quark found in the Ds+ meson. The pair of strange quarks is created as the gluon string breaks at the end closest to the heavy quark.

    When produced in high-energy collisions, quarks are never observed in isolation as free particles. Instead, all quarks remain connected to other fundamental particles produced in a collision by a “string” of gluons.

    At low energies, these gluons bind quarks and antiquarks together to form stable mesons. But at higher energies, the string can break and reconnect to new quark-antiquark pairs that are created out of the energy stored in the stretched string.

    We can watch this process in action by studying bottom or charm quarks, which are initially produced in proton-antiproton collisions. The bottom and charm quarks can ultimately be found inside a heavy meson, such as a B+ or D+, respectively. But once the quark is bound inside one of these particles, what happens to the rest of its string?

    Scientists have tuned models to describe the average properties of the mesons created in the fragmentation process, but it would be interesting to watch what happens to the end of the string that remains immediately after the part connected to the heavy quark is broken.

    Recently, the CDF experiment did exactly this by looking at the properties of kaons produced in association with Ds+ mesons.

    FNAL CDF
    CDF

    In this case, when a gluon string breaks, the strange quark in a K- is produced at the same time as the antistrange quark needed to form the Ds+ meson.

    Kaons produced in this way were shown to have distinctly different properties when compared to kaons produced in association with D+ mesons, which instead contain an antidown quark, consistent with fragmentation models.

    See the full article here.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 8:03 am on August 21, 2015 Permalink | Reply
    Tags: Accelerator Science, , ,   

    From DESY: “The Standard Model prevails – so far” 

    DESY
    DESY

    2015/08/20
    No Writer Credit

    1
    A top quark candidate in the CMS detector. Credit: CMS Collaboration

    2
    Top quark pair production cross section measurements compared to the Standard Model predictions as a function of the center-of-mass energy. The new result of the CMS collaboration at 13 TeV is displayed in red and is in agreement with the theory prediction (green band). Credit: CMS Collaboration

    CMS experiment publishes first test at new LHC energy of 13 TeV

    Shortly after the start of Run 2 at the in June 2015, scientists from DESY and their colleagues from the experiments CMS and ATLAS have performed a first important test of the Standard Model of particle physics at the new energy frontier, using data from proton-proton collisions at higher proton beam energies than ever achieved before. They looked at the production rate of a well-known particle called the top quark to see if it behaves differently at higher collision energies. Their study shows: it doesn’t.

    4
    A collision event involving top quarks

    CERN CMS Detector
    CMS

    CERN ATLAS New
    ATLAS

    3
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    Top quarks are the heaviest and among the most puzzling elementary particles. They weigh even more than the Higgs boson discovered in 2012 and might have a special connection to it. To analyse this relation and to test if the top quark is exactly the particle predicted by the current theory, physicists at the LHC perform high-precision measurements of the properties of the top quark.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    One of the most exciting studies to that respect is to measure the production rate, or cross section, for top quark pairs in the new energy range never explored before because it provides an excellent test of the Standard Model and might give scientists a first glimpse of new physics beyond.

    DESY scientists led the effort to measure the top quark pair production cross section at a proton-proton collision energy of 13 TeV. “The results are in good agreement with what we expected. This is a another huge success of the Standard Model,” said Alexander Grohsjean from DESY’s CMS group. The results are presented and discussed this week at the international high energy physics conference “XXVII International Symposium on Lepton Photon Interaction at High Energies”.

    See the full article here.

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    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 6:48 am on August 21, 2015 Permalink | Reply
    Tags: Accelerator Science, , , ,   

    From New Scientist: “Possible new particle hints that universe may not be left-handed” 

    NewScientist

    New Scientist

    19 August 2015
    Michael Slezak

    1
    Mirroring the universe (Image: Claudia Marcelloni/CERN)

    PHYSICS may be shifting to the right. Tantalising signals at CERN’s Large Hadron Collider near Geneva, Switzerland, hint at a new particle that could end 50 years of thinking that nature discriminates between left and right-handed particles.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Like your hands, some fundamental particles are different from their mirror images, and so have an intrinsic handedness or “chirality”. But some particles only seem to come in one of the two handedness options, leading to what’s called “left-right symmetry breaking”.

    In particular, W bosons, which carry the weak nuclear force, are supposed to come only in left-handed varieties. The debris from smashing protons at the LHC has revealed evidence of unexpected right-handed bosons.

    After finding the Higgs boson in 2012, the collider shut down for upgrades, allowing collisions to resume at higher energies earlier this year. At two of the LHC’s experiments, the latest results appear to contain four novel signals. Together, they could hint at a W-boson-like particle, the W’, with a mass of about 2 teraelectronvolts. If confirmed, it would be the first boson discovered since the Higgs.

    The find could reveal how to extend the successful but frustratingly incomplete standard model of particle physics, in ways that could explain the nature of dark matter and why there is so little antimatter in the universe.

    2
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    The strongest signal is an excess of particles seen by the ATLAS experiment (arxiv.org/abs/1506.00962), at a statistical significance of 3.4 sigma. This falls short of the 5 sigma regarded as proof of existence (see “Particle-spotting at the LHC“), but physicists are intrigued because three other unexpected signals at the independent CMS experiment could point to the same thing.

    CERN ATLAS New
    ATLAS

    CERN CMS Detector
    CMS

    “The big question is whether there might be some connection between these,” says Bogdan Dobrescu at Fermilab in Chicago. In a paper posted online last month, Dobrescu and Zhen Liu, also at Fermilab, showed how the signals could fit naturally into modified versions of left-right symmetric models (arxiv.org/abs/1507.01923). They restore left-right symmetry by introducing a suite of exotic particles, of which this possible W’ particle is one.

    Another way to fit the right-handed W’ into a bigger theory was proposed last week by Bhupal Dev at the University of Manchester, UK, and Rabindra Mohapatra at the University of Maryland. They invoke just a few novel particles, then restore left-right symmetry by giving just one of them special properties (arxiv.org/abs/1508.02277).

    Some theorists have proposed that these exotic particles instead hint that the Higgs boson is not fundamental particle. Instead, it could be a composite, and some of its constituents would account for the observed signals.

    “In my opinion, the most plausible explanation is in the context of composite Higgs models,” says Adam Falkowski at CERN. “If this scenario is true, that would mean there are new symmetries and new forces just around the corner.”

    “If the Higgs is really a composite particle, that would mean new forces just around the corner”

    The next step is for the existence of the right-handed W’ boson to be confirmed or ruled out. Dobrescu says that should be possible by October this year. But testing the broader theories could take a couple of years.

    See the full article here.

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  • richardmitnick 1:13 pm on August 7, 2015 Permalink | Reply
    Tags: Accelerator Science, , ,   

    From SLAC: “Unique SLAC Technology to Power X-ray Laser in South Korea” 


    SLAC Lab

    August 7, 2015

    1
    In a diligent, two-month-long process, SLAC engineers tested the first of the XL4 klystrons built for PAL. (SLAC National Accelerator Laboratory)

    Accelerator technology pioneered at the Department of Energy’s SLAC National Accelerator Laboratory is on its way to powering X-ray science in South Korea: On Aug. 6, the lab shipped one of its unique radio-frequency amplifiers – an XL4 klystron – to Pohang Accelerator Laboratory (PAL), where it will become a key component for the optimal performance of a new X-ray free-electron laser under construction.

    Klystrons are the driving force behind many particle accelerators. They generate powerful radio-frequency fields that provide the energy to bring charged particles up to speed for collision experiments and the production of intense X-rays.

    However, SLAC’s XL4 klystron, which operates in a particular frequency range known as the X-band, will serve another purpose at PAL: It will power accelerator structures that let scientists optimize the electron beam in the future X-ray laser.

    “We are the world’s experts for X-band radio-frequency accelerator technology,” says SLAC’s Michael Fazio, who leads the lab’s Technology Innovation Directorate (TID). “PAL and SLAC have a collaborative agreement under which SLAC is providing klystrons and other accelerator components for the new X-ray laser.”

    Optimizing X-ray Laser Performance in South Korea

    PAL is building an X-ray laser similar to SLAC’s Linac Coherent Light Source (LCLS), a DOE Office of Science User Facility that generates the most powerful X-rays on Earth. With their extremely bright and ultrashort light pulses, X-ray lasers enable groundbreaking research in many scientific areas, from materials science to biology to studies of matter in extreme conditions.

    SLAC LCLS Inside
    LCLS interior

    These state-of-the-art light sources produce X-ray light by sending short electron bunches on a wavy path inside special magnets.

    “For the best X-ray laser performance, the electron bunches must be very short, on the order of only tens to hundreds of a quadrillionth of a second,” says SLAC engineer Erik Jongewaard, the project leader of the collaboration with PAL. “However, bunches produced by the laser’s electron source itself are too long and need to be shortened by bunch compressors.”

    This is where SLAC’s XL4 klystron comes in: It delivers energy to a so-called X-band linearizer – an accelerator structure that manipulates bunches in such a way that they can be optimally shortened in the subsequent bunch compressor.

    “This manipulation can conveniently be done in the X-band,” Jongewaard says. “When it comes to X-band accelerator technology, SLAC is the only place in the world where you can go from concept through design, engineering, fabrication, testing and operation all in one place and where the entire system can be specified and optimized.”

    For the South Korean X-ray laser project, PAL therefore began collaborating with SLAC in 2012.

    “Under the $3.4-million agreement, our team built the linearizer components including two XL4 klystrons,” says SLAC’s Lisa Bonetti, head of the TID Advanced Prototyping, Fabrication and Test Facilities department. “We also trained PAL engineers here on site in using our X-band technology.”

    The first klystron and other parts are now on their way to PAL. The second klystron, which will serve as a spare but could potentially also be used in a tool to diagnose the X-ray laser’s electron and X-ray beams, is currently being tested.

    Exporting Expertise Built on Decades of Research

    SLAC’s unparalleled expertise with X-band technology goes back to the 1980s when researchers began thinking about an energy upgrade of the lab’s 2-mile-long linear accelerator to enable new particle physics experiments. Given the choice of either building an even longer accelerator or developing klystrons that drive particles to higher energies, scientists opted for the latter. This marked the birth of SLAC’s X-band program.

    Although the linear accelerator never got its energy upgrade, the X-band technology kept developing. The latest klystron model is the XL4 – an extraordinarily stable radio-frequency source with 50 million watts of peak power. At SLAC, two of them are integrated into LCLS while others power experiments at the lab’s Next Linear Collider Test Accelerator (NLCTA) and Accelerator Structure Test Area (ASTA).

    “SLAC has built a total of 22 XL4 klystrons to date, including a modified version, called the XL5, for accelerator facilities in Europe,” Jongewaard says. “Three are used in Switzerland: one at CERN and two at the Paul Scherrer Institute. We also built another two for the Elettra research center in Italy.” The XL5 model is now commercially produced by Communications & Power Industries, a Palo Alto-based company.

    Soon, SLAC’s X-band radio-frequency technology will also benefit science in East Asia: Hopes are that PAL’s X-ray laser will produce its first light in 2016.

    2
    Members of the Advanced Prototyping, Fabrication and Test Facilities department of SLAC’s Technology Innovation Directorate and engineers of the Pohang Accelerator Laboratory (PAL) in South Korea gather next to an XL4 klystron – a unique high-power radio-frequency amplifier used to accelerate and manipulate particle beams. Over the past 20 months, SLAC has built two klystrons and other parts needed to optimize the performance of PAL’s future X-ray laser. (SLAC National Accelerator Laboratory)

    See the full article here.

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    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
    i1

     
  • richardmitnick 12:32 pm on August 7, 2015 Permalink | Reply
    Tags: Accelerator Science, , ,   

    From FNAL “Frontier Science Result: NOvA sees electron neutrinos 

    FNAL II photo

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Aug. 7, 2015
    Alexander Radovic, College of William and Mary

    1
    This event in the NOvA far detector in Minnesota, shown from two different viewpoints, is a candidate electron neutrino interaction.

    Neutrino physicists have had a rich and storied relationship with the little neutral ones. First suggested by Wolfgang Pauli as a solution to the problem of missing energy in radioactive decay these light neutral particles have always proven to be as frustrating as they are fascinating. Pauli himself famously said, “I have done a terrible thing, I have postulated a particle that cannot be detected.”

    But detect it physicists did, and we found it to be even stranger than we first expected. Perhaps most fascinating is the fact that neutrinos change among the seemingly distinct types as they travel. Physicists around the world and at Fermilab have made much progress in understanding these neutrino oscillations, but key questions remain unanswered. Does the ordering of neutrino masses match our intuition based on what we know of other families of particles, or is it inverted? Do neutrinos oscillate the same as antineutrinos? These questions are themselves compelling and tie in to grander theories. For example, leptogenesis seeks to explain why our universe has far more matter than antimatter.

    Many experiments have worked to answer these questions. At Fermilab the NuMI muon neutrino beam enables a program of study of neutrino oscillations.

    FNAL NUMI Tunnel project
    FNAL NuMI muon neutrino beam tunnel

    Over the long journey from Fermilab to northern Minnesota, these neutrinos change type. The MINOS experiment has already used this beam to study the disappearance of muon neutrinos. The NOvA experiment is now providing another key piece of the puzzle by studying the appearance of electron neutrinos.

    FNAL NOvA experiment
    NOvA

    In many ways the entire NOvA experiment was optimized to see electron neutrino appearance. The detector has a high resolution and is instrumented with specialized photodetectors such that it can resolve the key signatures of an electron neutrino interaction. Excellent timing systems allow us to disentangle neutrino beam events from cosmic activity. The NuMI beam is operating at its highest-ever power to provide as many neutrinos as possible to the experiment, and the detector is off the main axis of the NuMI beam so it sees neutrinos at the perfect energy.

    The first measurement of electron neutrino appearance by NOvA has also required a complex analysis of our data, using sophisticated image processing algorithms trained on large sets of simulated data to pull out a pure sample of electron neutrino candidates and data-driven studies using beam and cosmic events at our near and far detectors. Four graduate students will earn their doctorates with their work on this result, and more have made significant contributions.

    The first appearance result, presented at Thursday’s Joint Experimental-Theoretical Seminar, shows six events selected with our primary analysis and 11 with our secondary analysis, with an expected background of approximately one in each case. This observation proves conclusively that the NOvA experiment can measure electron neutrino appearance and confirms oscillations at greater than 3 sigma with our primary analysis or 5 sigma with our secondary analysis. While this first result represents one-twelfth of the final exposure, it has already reached excellent agreement with measurements from existing experiments such as MINOS and T2K.

    NOvA has shown that it will be able to contribute significantly to the world’s knowledge of neutrino oscillations in the coming decade. It also represents a start of another exciting road as we set out to make the best possible use of world-class detectors and a world-class beam to provide leading discoveries using electron neutrino appearance.

    See the full article here.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 4:01 pm on August 4, 2015 Permalink | Reply
    Tags: Accelerator Science, , , , , Richard Dawkins Foundation   

    From Don Lincoln via Richard Dawkins Foundation: “Physicists find surprising ‘liquid-like’ particle interactions in Large Hadron Collider” 

    Richard Dawkins Foundation

    Richard Dawkins Foundation

    FNAL Don Lincoln
    Don Lincoln

    2
    Rice undergraduate student Benjamin Tran, graduate student Michael Northup, postdoctoral student Maxime Guilbaud and graduate students Zhenyu Chen and Zhoudunming Tu were part of the Rice team of physicists on the Large Hadron Collider’s Compact Muon Solenoid experiment that co-authored a paper describing the unexpected particle interactions from proton and lead-nuclei collisions. Credit: Zhoudunming Tu

    Three years ago, Rice physicists and their colleagues on the Large Hadron Collider’s (LHC’s) Compact Muon Solenoid (CMS) experiment stumbled on an unexpected phenomenon.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    CERN CMS Detector
    LHC with CMS (bottom)

    Physicists smashed protons into lead nuclei at nearly the speed of light, which caused hundreds of particles to erupt from these collisions. But that wasn’t the surprise. What was surprising is where these particles went: Rather than spreading out evenly in all directions, the particles coming out of the collisions preferentially lined up in a specific direction.

    Now, the Rice team has co-authored a paper that describes the unexpected particle interactions from these proton and lead-nuclei collisions.

    Particle detectors are shaped a little like a soup can. In these kinds of collisions, there is a tendency for particles to amass in a line along the axis of the can known as a “ridge.” Up until now, physicists understood a lot about what happens when a pair of protons or a pair of lead nuclei collide, but not a lot about what happens when a proton hits a lead nucleus: Would the hot nuclear matter coming out of the collision act like protons colliding, in which the post-collision particles coast along without feeling the effect of their neighbors? Or would the particles coming out of proton and lead collisions act in a more collective, liquid-like way as in lead-nuclei collisions?

    See the full article here.

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  • richardmitnick 10:18 am on August 2, 2015 Permalink | Reply
    Tags: Accelerator Science, , ,   

    Don Lincoln of FNAL: LHC Computing – Video 

    FNAL II photo

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    The LHC is the world’s highest energy particle accelerator and scientists use it to record an unprecedented amount of data. This data is recorded in electronic format and it requires an enormous computational infrastructure to convert the raw data into conclusions about the fundamental rules that govern matter. In this video, Fermilab’s Dr. Don Lincoln gives us a sense of just how much data is involved and the incredible computer resources that makes it all possible.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles

    LHC at CERN

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
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