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  • richardmitnick 7:49 pm on August 27, 2014 Permalink | Reply
    Tags: , , Fermilab Tevatron, , ,   

    From isgtw: “Preserving three decades of Tevatron data” This is important. 


    international science grid this week

    August 27, 2014
    Hanah Chang

    No longer active, the Tevatron was host to the Collider Detector at Fermilab (CDF) and DZero experiments, and is recognized for the discovery of the top quark and for providing evidence for the existence of the Higgs boson, which was confirmed at CERN in 2012. Several years later, there is a continued effort to preserve the data resulting from the Tevatron’s three-decade legacy.

    Fermilab CDF
    CDF at Fermilab

    Fermilab DZero
    DZero at Fermilab

    Tevatron
    Tevatron

    The Run II Data Preservation system is expected to be sustainable through the year 2020. The project is moving progressively, having successfully tested both the CDF and DZero pilot systems. Tape migration is continuing on schedule, and both the hardware and software infrastructures have been running since February 2012. One of the biggest misconceptions about what data preservation entails, is that only the data is preserved on tape — when, in fact, the more difficult task is preserving the software and an environment on which it can run.

    Willis Sakumoto, a senior scientist at Fermi National Accelerator Laboratory (Fermilab), confirms ongoing efforts to fully integrate CDF data into the Fermilab Intensity Frontier Structure and provide Run II documentation within the scope of the project. These efforts include running compatibility validation tests for the transition from Root4 to Root5, as well as the integration of the Cern Virtual Machine File System (CernVM-FS). “The project is well on its way to accomplishing its goal of handing off CDF analysis and documentation infrastructure to Fermilab Scientific Computing Division (FSCD) operations.”

    Michelle Brochmann, a student working on the DZero data preservation project, is also optimistic about the progress made thus far. “CernVM-FS facilitates cooperation among scientists by enabling them to access a consistent computational analysis environment.” It has some nice features: the software appears local despite being stored remotely, and files are accessed quickly because CernVM-FS uses optimized, existing http infrastructure and only fetches files from the remote server as they are needed. “Fermilab has committed to help maintain the CernVM-FS for the next decade or so,” adds Brochmann.

    Challenges the Run II Data Preservation team must overcome include lack of new resources and manpower. Fortunately, scientists like Kenneth Herner and Bo Jayatilaka — who have worked on the DZero and CDF experiments respectively — recognize the value of the labor they are putting forth and the overall significance it could have for a scientist who may need to revisit a measurement or make new theoretical calculations. “This data has the potential to make new discoveries,” says Jayatilaka.

    The growing spread of digital science means not only data but also software preservation is of critical importance to the long-term value of research outcomes. As the magnitude of the experiments — both in cost and in labor — increase, the need for a common forum of usable data is amplified. In response, projects such as the Data and Software Preservation for Open Science (DASPOS) and the Study Group for Data Preservation in High Energy Physics (DPHEP) are working to expand and improve data preservation technology.

    Sakumoto is planning to integrate the use of cloud-based technology as a possible analysis solution. Regardless of the methodology chosen, the need for sustainable data preservation will continue to increase as science advances, experiments become less replicable, and data sets become more unique.

    See the full article here.

    iSGTW is an international weekly online publication that covers distributed computing and the research it enables.

    “We report on all aspects of distributed computing technology, such as grids and clouds. We also regularly feature articles on distributed computing-enabled research in a large variety of disciplines, including physics, biology, sociology, earth sciences, archaeology, medicine, disaster management, crime, and art. (Note that we do not cover stories that are purely about commercial technology.)

    In its current incarnation, iSGTW is also an online destination where you can host a profile and blog, and find and disseminate announcements and information about events, deadlines, and jobs. In the near future it will also be a place where you can network with colleagues.

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  • richardmitnick 10:20 am on August 12, 2014 Permalink | Reply
    Tags: , , Fermilab Tevatron, , ,   

    From Fermilab: “From the Deputy Director – CMS excitement” 


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

    Tuesday, Aug. 12, 2014
    jl
    Joe Lykken

    When I joined the CMS collaboration seven years ago, I was motivated both by the exciting discovery potential of the Large Hadron Collider and by the fact that many of my friends from the Tevatron experiments were starting to move into leading roles for CMS. In the years leading up to the July 4, 2012, announcement of the Higgs boson discovery, I witnessed from the inside how the momentum carried over from the Tevatron era enabled, on many levels, the remarkable success of the CMS experiment.

    Fermilab Tevatron
    Tevatron rings

    CERN CMS New
    CMS at CERN’s LHC

    Fermilab DZero
    DZero at the Tevatron

    Fermilab CDF
    CDF at the Tevatron

    But wait — there’s more. The LHC will be turning on again early next year with both higher collision energy and higher “luminosity” — the rate at which collisions occur. This raises the prospects for many kinds of discoveries, including new heavy particles (perhaps the “superpartners” predicted by my favorite theory, supersymmetry), or unexpected properties of the Higgs boson. I have placed a friendly bet with Tom LeCompte, the former ATLAS collaboration physics coordinator and our Argonne neighbor, that superpartners will in fact be discovered by CMS and ATLAS during this next LHC run.

    CERN LHC Map
    LHC at CERN

    CERN ATLAS New
    ATLAS at CERN

    Supersymmetry standard model
    Standard Model of Supersymmetry

    Continued success of the CMS experiment requires significant upgrades to the CMS detector to meet the challenges of higher-luminosity running. The U.S. CMS collaboration has taken responsibility for upgrading three major subsystems in a Phase I upgrade project jointly funded by the Department of Energy and the National Science Foundation.

    Last week, this U.S. CMS project passed the simultaneous CD-2/CD-3 reviews, allowing these crucial upgrades to proceed. It was all smiles at the closeout last Thursday. This achievement reflects excellent work by the CMS Detector Upgrade Project team led by Steve Nahn, with deputies Aaron Dominguez and Lucas Taylor, involving CMS collaborators from many universities and labs and lots of talented people at Fermilab.

    A proud day for U.S. CMS, with many more to come.

    See the full article here.

    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.

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  • richardmitnick 11:30 am on July 17, 2014 Permalink | Reply
    Tags: , , Fermilab Tevatron, , ,   

    From Fermilab: “Measuring a fractional charge” 


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

    Thursday, July 17, 2014
    Leo Bellantoni

    In 1909, Robert Millikan and Harvey Fletcher performed a Nobel Prize-winning experiment that showed that elementary particles always have a specific amount of electric charge and that fractional charges do not exist. Now, a century later, we measure fractional charges.

    two
    At left is the apparatus used by Robert Millikan and his student to measure the charge of the electron in the early 20th century. At right is the apparatus used by more than 300 physicists — including students — to measure the charge of the top quark in the early 21st century.

    To be fair, in Millikan’s time, there were few known particles to work with. His experiment was done using electrons, although by inference the result also applies to protons. Particles called quarks were unknown to Millikan and are quite different from electrons. They should have charges of either +2/3 or -1/3 times that of the electron.

    We say “should have charges” because quarks are (nearly) always found inside hadrons, such as protons and neutrons, where they are bound very tightly to other quarks. Unlike electrons, you can’t find just one and measure it. Consequently, the charge assignments for quarks are inferred from the charges of hadrons and from our model of the various quarks that are inside hadrons.

    The top quark is a little different though. Because of its large mass, the top quark decays before becoming bound up in a hadron. Electrical charge being conserved, we know that if we identify the particles that a top quark decays into and add up their electrical charges, then we have the charge of the top quark.

    The tricky part is identifying which particles measured at the Tevatron are the ones that come from the decaying top quark. There is so much energy in Tevatron collisions that the available energy E results in the mc2 of many particles, not all of which are the products of top quark decay.

    Fermilab Tevatron
    Fermilab Tevatron map

    In “lepton + jets” events, there is always a very energetic electron or muon, which very likely is the product of the top decay. The other “particle” produced in that top quark decay is a jet, a narrow spray of particles that are all going in the same direction. They are produced from the decays of a single particle; in the Standard Model, that progenitor is a bottom quark. To determine the charge of the progenitor, we count the charges of all the particles in a jet. Because the more energetic particles are more likely to reflect the progenitor’s charge, we count their charges more heavily in our summation.

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    The prediction of the Standard Model is quite clear: the top quark’s charge should be positive and 2/3 times that of the electron. However, it is still possible that the top quarks that are produced by the Tevatron are not what we think they are. There is some possibility that it is instead an exotic particle with a negative charge 4/3 times that of the electron.

    To check on this possibility, the DZero collaboration used these methods to measure the electrical charge of the top quark. Because there are only two possible answers, +2/3 and -4/3, the primary result is to determine which of the two options is more likely and how much more likely it is. We find with a very high level of confidence that the +2/3 answer is the right one. The probability that an exotic top quark could have given our result is only one in about 16 million. As far as its electric charge is concerned, the top quark looks just as predicted in the Standard Model of elementary particles.

    Fermilab DZero
    Fermilab/DZero

    See the full article here.

    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.


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