Tagged: CERN LHC Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 9:05 am on June 4, 2015 Permalink | Reply
    Tags: , CERN LHC, , , , ,   

    From DOE via FNAL: “U.S. joins the world in a new era of research at the Large Hadron Collider” 

    FNAL Home

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

    The following news release about the restart of the Large Hadron Collider is being issued by the U.S. Department of Energy’s Fermi National Accelerator Laboratory on behalf of the U.S. scientists working on the LHC. Fermilab serves as the U.S. hub for the CMS experiment at the LHC and the roughly 1,000 U.S. scientists who work on that experiment, including about 100 Fermilab employees. Fermilab is a Tier 1 computing center for LHC data and hosts a Remote Operations Center to process and analyze that data. Read more information about Fermilab’s role in the CMS experiment and the LHC. See a list of Fermilab scientists who can speak about the LHC.

    1
    One of the first collisions in the CMS detector at the record-high energy of 13 TeV, taken during testing for the second run of the Large Hadron Collider in late May. Image: CMS/CERN

    New LHC data gives researchers from around the world their best chance yet to study the Higgs boson and search for dark matter and new particles.

    Today scientists at the Large Hadron Collider at CERN, the European research facility, started recording data from the highest-energy particle collisions ever achieved on Earth.

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

    This new proton collision data, the first recorded since 2012, will enable an international collaboration of researchers that includes more than 1,700 U.S. physicists to study the Higgs boson, search for dark matter and develop a more complete understanding of the laws of nature.

    “Together with collaborators from around the world, scientists from roughly 100 U.S. universities and laboratories are exploring a previously unreachable realm of nature,” said James Siegrist, the U.S. Department of Energy’s associate director of science for high-energy physics. “We are very excited to be part of the international community that is pushing the boundaries of our knowledge of the universe.”

    The Large Hadron Collider, the world’s largest and most powerful particle accelerator, reproduces conditions similar to those that existed immediately after the big bang. In 2012, during the LHC’s first run, scientists discovered the Higgs boson—a fundamental particle that helps explain why certain elementary particles have mass. U.S. scientists represent about 20 percent and 30 percent, respectively, of the ATLAS and CMS collaborations, the two international teams that co-discovered the Higgs boson. Hundreds of U.S. scientists played vital roles in the Higgs discovery and will continue to study its remarkable properties.

    CERN ATLAS New
    ATLAS

    CERN CMS Detector
    CMS

    Scientists will use this new LHC data to pin down properties of the Higgs boson and search for new physics and phenomena such as dark matter particles—an invisible form of matter that makes up 25 percent of the entire mass and energy of the universe. Physicists will also endeavor to answer questions such as: Why is there more matter than antimatter? Why is the Higgs boson so light? Are there additional types of Higgs particles? What did matter look like immediately after the big bang?

    NSF-funded researchers at ATLAS, CMS and LHCb are investigating some of nature’s most fundamental properties at collision energies never before explored.

    CERN LHCb New II
    LHCb

    The potential for transformative discoveries is profound,” said Denise Caldwell, NSF’s division director for physics. “We eagerly look forward to LHC operation at almost twice the energy of any other particle accelerator on Earth.”

    The LHC was turned off in early 2013, and engineers spent two years preparing the machine to collide particles at a much higher energy and intensity. During the shutdown, U.S. scientists and their international collaborators installed several new components in the four LHC detectors. These components, together with other upgrades, will allow physicists to record more information about the particles produced during the high-energy collisions.

    These upgrades included a new detector in the heart of the ATLAS experiment, several new muon detectors on the outer shell of the CMS experiment, a new calorimeter inside the ALICE experiment and an innovative new data sorting system for the LHCb experiment.

    CERN ALICE New II
    ALICE

    U.S. scientists played vital roles in the design and instrumentation of these new systems and will operate several of the detector components throughout the next three years of data collection.

    Once collected at CERN in Geneva, Switzerland, the new LHC data travels the globe. New fiber optic cables recently installed by the U.S. Department of Energy bring the data to computers and data centers at 18 U.S. institutions, which provide 35 percent of the worldwide computing power for the CMS experiment and 23 percent for the ATLAS experiment.

    The upgraded LHC will also generate data at a much faster rate. Scientists predict they will match the amount of data generated throughout the collider’s first three-year run within the next five months, eventually accumulating 10 times more data by the end of 2017. These collisions will also produce Higgs bosons 25 percent faster and will increase the chances of seeing other theoretical particles, such as those predicted for supersymmetry, by over 40 percent.

    “The first three-year run of the LHC, which culminated with major discovery in July 2012, was only the start of our journey. It is time for new physics!” said CERN Director-General Rolf Heuer. “We have seen first data beginning to flow. Let’s see what they will reveal to us about how our universe works.”

    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. India, Japan, the Russian Federation, the United States of America, Turkey, the European Union, JINR and UNESCO have Observer Status.

    The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

    The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2015, its budget is $7.3 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 48,000 competitive proposals for funding and makes about 11,000 new funding awards. NSF also awards about $626 million in professional and service contracts yearly.

    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.

     
  • richardmitnick 2:10 pm on June 3, 2015 Permalink | Reply
    Tags: , CERN LHC,   

    From Don Lincoln of FNAL: Video -“The LHC Experiments” 

    The Large Hadron Collider or LHC is the world’s biggest particle accelerator, but it can only get particles moving very quickly. To make measurements, scientists must employ particle detectors. There are four big detectors at the LHC: ALICE, ATLAS, CMS, and LHCb. In this video, Fermilab’s Dr. Don Lincoln introduces us to these detectors and gives us an idea of each one’s capabilities.

    Watch, enjoy, learn.

    See the full article here.

    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

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 9:55 am on May 29, 2015 Permalink | Reply
    Tags: , CERN LHC, , ,   

    From CERN: “Major work to ready the LHC experiments for Run 2″ 

    CERN New Masthead

    29 May 2015
    Corinne Pralavorio

    1
    A magnet is lowered through the ALICE cavern for work on the Large Hadron Collider during Long Shutdown 1 (Image: Maximilien Brice/CERN)

    2
    Installation of a new layer of pixels in the ATLAS tracker (Image: Claudia Marcelloni/CERN)

    3
    The installation of the new pixel luminosity telescope in the CMS detector (Image: Maximilien Brice/CERN)

    4
    The reinstallation of the beam pipe in the LHCb detector (Image: LHCb)

    Next week, the experiments at the Large Hadron Collider (LHC) will be back in action, taking data for the accelerator’s second run. The experiments were shut down two years ago for maintenance and refurbishment in preparation for collisions at the higher energy of 13 teraelectronvolts (TeV).

    Long Shutdown 1 (LS1) saw hundreds of collaboration members working in and around the experiment caverns on improvements to the detectors. Four of these detectors – ALICE, ATLAS, CMS and LHCb – are enormous, sophisticated machines measuring up to 40 metres long and 20 metres long and made up of dozens of subdetectors, themselves composed of millions of sensitive sensors. Each subdetector is designed to determine the characteristics of one or more types of particle emerging from the particle collisions. These subdetectors include trackers, which reveal the paths of charged particles, and calorimeters, which measure the energy of some particles. All the data collected is grouped and analysed with a view to understanding what happened at the moment of collision. During the second run, up to one billion proton collisions could occur every second in the detectors. Most of the collisions do not yield interesting results and given the enormous quantities of data generated, it can’t all be logged. The trigger system therefore sorts the collisions, keeping just the most interesting events – several hundred per second. The data-acquisition system then records the data and sends it to the Worldwide LHC Computing Grid to be analysed by physicists. During the long shutdown, all these systems were verified and some were renovated or upgraded. Below is an overview of the main work projects that took place in the detector caverns ahead of the big restart.

    ALICE

    This experiment, which studies quark-gluon plasma – the matter present in the first moments of the universe’s existence – made improvements to most of its 19 subdetectors. One of these was the electromagnetic calorimeter, which measures the energy of the electrons, positrons and photons produced by the collisions. Its range of detection was extended with the addition of the new di-jet calorimeter. Modules were also added to other subdetectors, and tens of kilometres of cables were replaced as part of a complete overhaul of the electrical infrastructure. In terms of computing, ALICE doubled its data-logging capacity with improvements to the trigger and data-acquisition systems carried out by the collaboration’s IT experts.

    ATLAS

    The ATLAS detector can now see even better, thanks to a fourth layer of pixels in its pixel tracker, the subdetector closest to the collisions and whose function is to reconstruct the particle trajectories. Improvements were also made to the muon detectors and calorimeters, as well as to the entire basic infrastructure (including the electrical power supply and the cooling systems). Sections of the beam pipe, in which the protons circulate and collide, were replaced to reduce the background noise in the detector. With new, more efficient trigger and data-acquisition systems, ATLAS is ready to log more data than before: it will be capable of recording a thousand events every second – more than double its capacity during Run 1. In addition, an improvement plan to upgrade the simulation, reconstruction and data-analysis software used by physicists to conduct their research was carried out.

    CMS

    The CMS collaboration carried out important work on its tracker so that it can function at lower temperatures: it was fitted with a new leak-tightness system and a refurbished cooling system. The central section of the beam tube, where the collisions take place, was replaced with a tube of a smaller diameter to allow a new pixel tracker to be installed during the next long shutdown. A brand-new subdetector, the pixel luminosity telescope, was installed on either side of the detector and will enhance the experiment’s ability to measure luminosity (a measure of the number of collisions produced in the experiment). New muon chambers were installed and the hadron calorimeter, which measures the energy of particles containing quarks, was fitted with upgraded photodetectors. Last but not least, the trigger system was improved and the software and computing systems underwent a significant overhaul to reduce the time needed to produce analysis datasets.

    LHCb

    LHCb, the experiment that investigates beauty particles, added a HeRSChel detector along the beam line in order to identify rare processes in which particles are observed inside the detector but not along the beam line itself. The experiment’s beam pipe was also replaced, as was the pipe’s supporting structure, which is now lighter and more “transparent”. The experiments are constantly striving to achieve transparency as the detectors must detect without influencing the results, for example by intercepting particles that they’re not supposed to stop or by altering the trajectories.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 8:28 am on May 22, 2015 Permalink | Reply
    Tags: , CERN LHC, , , ,   

    From CERN: “First images of collisions at 13 TeV” 

    CERN New Masthead

    21 May 2015
    Cian O’Luanaigh

    1
    Test collisions continue today at 13 TeV in the Large Hadron Collider (LHC) to prepare the detectors ALICE, ATLAS, CMS, LHCb, LHCf, MOEDAL and TOTEM for data-taking, planned for early June (Image: LHC page 1)

    Last night, protons collided in the Large Hadron Collider (LHC) at the record-breaking energy of 13 TeV for the first time. These test collisions were to set up systems that protect the machine and detectors from particles that stray from the edges of the beam.

    A key part of the process was the set-up of the collimators. These devices which absorb stray particles were adjusted in colliding-beam conditions. This set-up will give the accelerator team the data they need to ensure that the LHC magnets and detectors are fully protected.

    Today the tests continue. Colliding beams will stay in the LHC for several hours. The LHC Operations team will continue to monitor beam quality and optimisation of the set-up.

    This is an important part of the process that will allow the experimental teams running the detectors ALICE, ATLAS, CMS, LHCb, LHCf, MOEDAL and TOTEM to switch on their experiments fully. Data taking and the start of the LHC’s second run is planned for early June.

    2
    Protons collide at 13 TeV sending showers of particles through the ALICE detector (Image: ALICE)

    3
    Protons collide at 13 TeV sending showers of particles through the CMS detector (Image: CMS)

    4
    Protons collide at 13 TeV sending showers of particles through the ATLAS detector (Image: ATLAS)

    5
    Protons collide at 13 TeV sending showers of particles through the LHCb detector (Image: LHCb)

    6
    Protons collide at 13 TeV sending showers of particles through the TOTEM detector (Image: TOTEM)

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 10:59 am on May 20, 2015 Permalink | Reply
    Tags: , , CERN LHC, , ,   

    From Nature: “Billion-dollar particle collider gets thumbs up” 

    Nature Mag
    Nature

    19 May 2015
    Edwin Cartlidge

    1
    Brookhaven National Laboratory in New York is a potential host for the Electron-Ion Collider. Brookhaven National Laboratory/CC BY-NC-ND 2.0

    A machine that would allow scientists to peer deeper than ever before into the atomic nucleus is a big step closer to being built. A high-level panel of nuclear physicists is expected to endorse the proposed Electron-Ion Collider (EIC) in a report scheduled for publication by October. It is unclear how long construction would take.

    The panel is the [DOE] Nuclear Science Advisory Committee, or NSAC, which produces regular ten-year plans for the US Department of Energy (DOE) and the National Science Foundation. Its latest plan is still being finalized, but NSAC’s long-range planning group “strongly recommended” construction of the EIC at a meeting last month, says NSAC member Abhay Deshpande, a nuclear physicist at Stony Brook University in New York. The EIC will almost certainly be formally endorsed in the NSAC report, he says. It must then be approved by the DOE, but most projects backed by the expert panel have come to fruition, he says.

    The collider would allow unprecedented insights into how protons and neutrons are built up from quarks and the particles that act between them, known as gluons.

    The current leading facilities for studying quark–gluon matter are the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in Upton, New York, and the Large Hadron Collider at CERN, Europe’s particle-physics laboratory near Geneva, Switzerland.

    BNL RHIC Campus
    BNL RHIC
    BNL RHIC

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

    These facilities smash protons and heavy ions together to recreate the energetic conditions of the early Universe, when quarks and gluons existed as a plasma rather than in atomic nuclei. The EIC would collide point-like electrons with either protons or heavy ions, generating collisions that have a similarly high energy but are more precise and so can be used to study subatomic particles in detail.

    In particular, the EIC would be ideal for studying an exotic state of matter that is made up entirely of gluons. The machine should also solve a puzzle about the proton that has baffled physicists for nearly 30 years. The proton has a quantum-mechanical property called spin, but, strangely, the spins of its three constituent quarks add up to only about one-third of its own spin. The EIC would determine what makes up the difference: options include the spin of the proton’s gluons, the angular momentum of its quarks or of the gluons from their orbital motion, or a mixture of all three.

    “Until we have the EIC, there are huge areas of nuclear physics that we are not going to make progress in,” says Donald Geesaman, a nuclear physicist at Argonne National Laboratory in Illinois, and the chair of NSAC.

    The machine would not be built from scratch. One option is to add an electron-beam facility to RHIC — a plan that is estimated to cost about US$1 billion and would depend on some as-yet-unproven technologies. Another is to add an ion accelerator and new collider rings to the Continuous Electron Beam Accelerator Facility [CEBAF] at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, which would cost about $1.5 billion.

    Jlab CEBAF
    CEBAF at JLab

    Deshpande hopes that the DOE will give the collider the thumbs up within a year of the NSAC plan’s publication. Two or three more years would be needed to finalize the competing bids and choose one, meaning that construction could start in about 2020 and be completed five years later, he says.

    Others say that this outlook is too rosy. The 2008 financial crisis led to a drop in science funding that forced NSAC to review its 2007 ten-year plan. A specially formed subcommittee concluded in 2013 that RHIC would have to shut down if funding for the DOE’s Office of Nuclear Physics remained flat over the following five years. In fact, those funds have grown slightly, keeping RHIC in business, but the scare led to a more cautious approach this time around, says Geesaman. He points out that when the DOE and the National Science Foundation commissioned the ten-year plan, they specified that NSAC should consider what US physicists could achieve if funding remained flat, as well as how much support they would need to maintain a “world-leadership position”.

    Robert McKeown, deputy director for science at the Jefferson lab, thinks that limited funds might delay the start up of the EIC until at least 2030. And Michael Lubell, director of public affairs at the American Physical Society, questions whether it is feasible for the EIC to be built by the United States alone. He notes that the $1.5-billion Long-Baseline Neutrino Experiment became an international project [DUNE managed by FNAL] after a slimmed-down $600-million version failed to pass scientific muster. “It is hard to see how to do this unless you get international buy-in,” he says.

    Deshpande thinks that the United States can go it alone. But he notes that collaborations at CERN and in China are also developing plans for electron–ion colliders and that the three groups are already exchanging ideas.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
  • richardmitnick 10:51 am on March 27, 2015 Permalink | Reply
    Tags: , , CERN LHC,   

    From FNAL- “Frontier Science Result: CMS Rule of three 

    FNAL Home

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

    March 27, 2015
    Jim Pivarski

    CERN CMS New
    CMS

    1
    The three-fold symmetry of electrons, muons and taus may be broken by Higgs decays. (Design adapted from a neolithic spiral and the flag of Sicily.)

    In Rendezvous with Rama, Arthur C. Clarke imagined an artifact built by aliens who have three arms with three fingers each, so everything about it has a three-fold symmetry. One could argue that our fondness for bilateral symmetries (in the design of cars, planes, cathedrals, etc.) comes from the ubiquity of this shape in life on Earth, and creatures from other worlds might have developed differently. However, it is more surprising to find such a pattern imprinted on the universe itself.

    All particles of matter appear in threes: three generations of leptons and three generations of quarks. The second generation is a complete copy of the first with heavier masses, and the third generation is yet another copy. For instance, a muon is a heavy version of an electron, and a tau is a heavy muon. No one knows why matter comes in triplicate like this.

    For quarks, the symmetry isn’t perfect because W bosons can turn quarks of one generation into quarks of another generation. Something else transforms generations of neutrinos. But charged leptons — electrons, muons and taus — appear to be rigidly distinct. Some physicists suspect that we simply haven’t found the particle that mixes them yet.

    Or perhaps we have: Theoretically, the Higgs boson could mix lepton generations the way that the W boson mixes quarks. The Higgs decay modes haven’t all been discovered yet, so it’s possible that a single Higgs could decay into two generations of leptons at once, such as one muon and one tau. CMS scientists searched for muon-tau pairs with the right amount of energy to have come from a Higgs boson, and the results were surprising.

    They saw an excess of events. That is, they considered all the ways that other processes could masquerade as Higgs to muon-tau decays, estimated how many of these spurious events they should expect to find, and found slightly more. The word “slightly” should be emphasized — it is on the border of statistical significance, and other would-be discoveries at this level of significance (and stronger) have been shown to be flukes. On the other hand, if the effect is real, it would start as a weak signal until enough data confirm it.

    Naturally, the physics community is eager to see how this develops. The LHC, which is scheduled to restart soon at twice the energy of the first run, has the potential to produce Higgs bosons at a much higher rate — perhaps enough to determine whether this three-fold symmetry of leptons is broken or not.

    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.

     
  • richardmitnick 12:28 pm on March 17, 2015 Permalink | Reply
    Tags: , , CERN LHC, , , ,   

    From Symmetry: “Experiments combine to find mass of Higgs” 

    Symmetry

    March 17, 2015
    Sarah Charley

    1
    Illustration by Thomas McCauley and Lucas Taylor, CERN

    The CMS and ATLAS experiments at the Large Hadron Collider joined forces to make the most precise measurement of the mass of the Higgs boson yet.

    CERN CMS New II
    CMS

    CERN ATLAS New
    ATLAS

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC

    On the dawn of the Large Hadron Collider restart, the CMS and ATLAS collaborations are still gleaning valuable information from the accelerator’s first run. Today, they presented the most precise measurement to date of the Higgs boson’s mass.

    “This combined measurement will likely be the most precise measurement of the Higgs boson’s mass for at least one year,” says CMS scientist Marco Pieri of the University of California, San Diego, co-coordinator of the LHC Higgs combination group. “We will need to wait several months to get enough data from Run II to even start performing any similar analyses.”

    The mass is the only property of the Higgs boson not predicted by the Standard Model of particle physics—the theoretical framework that describes the interactions of all known particles and forces in the universe.

    3
    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    The mass of subatomic particles is measured in GeV, or giga-electronvolts. (A proton weighs about 1 GeV.) The CMS and ATLAS experiments measured the mass of the Higgs to be 125.09 GeV ± 0.24. This new result narrows in on the Higgs mass with more than 20 percent better precision than any previous measurements.

    Experiments at the LHC measure the Higgs by studying the particles into which it decays. This measurement used decays into two photons or four electrons or muons. The scientists used data collected from about 4000 trillion proton-proton collisions.

    By precisely pinning down the Higgs mass, scientists can accurately calculate its other properties—such as how often it decays into different types of particles. By comparing these calculations with experimental measurements, physicists can learn more about the Higgs boson and look for deviations from the theory—which could provide a window to new physics.

    “This is the first combined publication that will be submitted by the ATLAS and CMS collaborations, and there will be more in the future,” says deputy head of the ATLAS experiment Beate Heinemann, a physicist from the University of California, Berkeley, and Lawrence Berkeley National Laboratory.

    ATLAS and CMS are the two biggest Large Hadron Collider experiments and designed to measure the properties of particles like the Higgs boson and perform general searches for new physics. Their similar function allows them to cross check and verify experimental results, but it also inspires a friendly competition between the two collaborations.

    “It’s good to have competition,” Pieri says. “Competition pushes people to do better. We work faster and more efficiently because we always like to be first and have better results.”

    Normally, the two experiments maintain independence from one another to guarantee their results are not biased or influenced by the other. But with these types of precision measurements, working together and performing combined analyses has the benefit of strengthening both experiments’ results.

    “CMS and ATLAS use different detector technologies and different detailed analyses to determine the Higgs mass,” says ATLAS spokesperson Dave Charlton of the University of Birmingham. “The measurements made by the experiments are quite consistent, and we have learnt a lot by working together, which stands us in good stead for further combinations.”

    It also provided the unique opportunity for the physicists to branch out from their normal working group and learn what life is like on the other experiment.

    “I really enjoyed working with the ATLAS collaboration,” Pieri says. “We normally always interact with the same people, so it was a real pleasure to get to know better the scientists working across the building from us.”

    With this groundwork for cross-experimental collaboration laid and with the LHC restart on the horizon, physicists from both collaborations look forward to working together to increase their experimental sensitivity. This will enable them not only to make more precise measurements in the future, but also to look beyond the Standard Model into the unknown.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 1:20 pm on March 12, 2015 Permalink | Reply
    Tags: , CERN LHC, , , ,   

    From Don Lincoln at FNAL: The Detectors at the LHC 

    FNAL Home


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

    The Large Hadron Collider or LHC is the world’s biggest particle accelerator, but it can only get particles moving very quickly. To make measurements, scientists must employ particle detectors. There are four big detectors at the LHC: ALICE, ATLAS, CMS, and LHCb. In this video, Fermilab’s Dr. Don Lincoln introduces us to these detectors and gives us an idea of each one’s capabilities.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles

    CERN ALICE New II
    ALICE

    CERN ATLAS New
    ATLAS

    CERN CMS New
    CMS

    CERN LHCb New II
    LHCb

    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.

     
  • richardmitnick 12:46 pm on March 8, 2015 Permalink | Reply
    Tags: , , , CERN LHC   

    From BBC: “LHC restart: ‘We want to break physics'” 

    BBC
    BBC

    4 March 2015
    Jonathan Webb

    1
    Inside the CMS experiment, the beam pipe is dwarfed by huge cylindrical detectors that will try to capture everything that emerges from the collisions.

    As the Large Hadron Collider (LHC) gears up for its revamped second run, hurling particles together with more energy than ever before, physicists there are impatient. They want this next round of collisions to shake their discipline to its core.

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

    “I can’t wait for the switch-on. We’ve been waiting since January 2013 to have our proton beams back,” says Tara Shears, a particle physics professor from the University of Liverpool.

    Prof Shears is raising her voice over the occasional noise of fork-lift trucks and tools, as well as the constant hum of the huge experimental apparatus behind her: LHCb, one of four collision points spaced around the LHC’s 27km circumference.

    CERN LHCb New II
    LHCb

    All this noise reverberates because we are perched at the side of an imposing cavern, 30 storeys beneath the French-Swiss border.

    The other three experiments – Atlas, CMS and Alice – occupy similar halls, buried elsewhere on this famous circular pipeline.

    CERN ATLAS New
    ATLAS

    CERN ALICE New II
    ALICE

    ‘Everything unravels’

    In mid-March two beams of protons, driven and steered by super-cooled electromagnets, will do full circuits of the LHC in both directions – for the first time in two years. When that happens, there will be nobody between here and ground level. Then in May, if the protons’ practice laps proceed without a hitch, each of the four separate experiments will recommence its work: funnelling those tightly focussed, parallel beams into a head-on collision and measuring the results. For us, now, the other stations on the ring are a 10-20 minute drive away; for the protons, a lap will take less than one ten-thousandth of a second. They have the advantage of travelling a whisker under the speed of light.

    They are moving with so much energy that when they collide, things get hot. Historically hot. “We’re recreating temperatures that were last seen billionths of a second after the Big Bang,” Prof Shears explains. “When you get to this hot temperature, matter dissociates into atoms, and atoms into nuclei and electrons. “Everything unravels to its constituents. And those constituents are what we study in particle physics.”

    2
    The two beams of protons are focussed into a tiny, intense blast before being put on a collision course

    Alongside more pedestrian items, like electrons, or the quarks that combine to make protons and neutrons, these constituents include the world-famous Higgs boson.

    Higgs Boson Event
    Higgs Event

    This longed-for and lauded particle – the last major ingredient in the Standard Model of particle physics – was detected by the teams at Atlas and CMS in 2012.

    5

    Then in early 2013, after countless further collisions with valuable but less sensational results, the LHC was wound down for a planned hiatus.

    __________________________________________________________________________________

    What is an electronvolt?

    3

    Particle accelerators use strong electric fields to speed up tiny pieces of matter
    An electronvolt (eV) is the energy gained by one electron as it accelerates through a potential of one volt
    The LHC reaches particle energies measured in trillions of eV: teraelectronvolts (TeV)
    This is only the energy in the motion of a flying mosquito – per particle
    The LHC beams contain hundreds of trillions of particles, each travelling at 99.99999999% of the speed of light
    In total, an LHC beam has the energy of a TGV high-speed train travelling at 150 km/h

    __________________________________________________________________________________

    Renewed vigour

    The two intervening years have been spent servicing and improving the collider.

    “All the magnets have been surveyed, the connections between them have been X-rayed and strengthened, and all the electrical and cryogenic systems have been checked out and optimised,” Prof Shears says. This effort – between one and two million hours of work, all told – means that the LHC is now ready to operate at its “design energy”. Its initial run, after a dramatic false start in 2008, only reached a maximum collision energy of eight trillion electronvolts. That came after a boost in 2012 and the extra power delivered the critical Higgs observations within a few months.

    When they kick off in May, the proton collisions will be at 13 trillion electronvolts: a leap equivalent to that made by the LHC when it first went into operation and dwarfed the previous peak, claimed by the 6km Tevatron accelerator in the US. “It’s a really significant step in terms of what we might be able to see in the Universe,” says Prof Shears.

    “The design energy is a little higher again, at 14 TeV. We want to make sure that we can run close to it, first of all. If operations there are smooth, then subsequently, after next year, we can put the energy up that last little bit.” Alongside this radical hike in the beams’ energy, the experiments housed at the four collision sites have also had time to upgrade. Some have added extra detectors as well as finishing, mending or improving equipment that was built for the first run.

    Build it up, tear it down

    In a sense, one of the shiniest new items in the LHC’s armoury for Run Two is the Higgs boson. Now that its existence is confirmed and quantified, it can inform the next round of detection and analysis. “It’s a new door – a new tool that we can use to probe what is beyond the Standard Model,” says Dr Andre David, one of the research team working on the CMS experiment. Dr David is driving me from the CMS site, in France, back down the valley between the Jura Mountains and Lake Geneva to the main Cern headquarters. This main site, adjacent to the Atlas experiment, sits on the southern side of the LHC’s great circle and straddles the Swiss border.

    4
    5
    Data flow: The LHC has immeasurable miles of cables to carry experimental data – as well as better mobile phone signal than you can get at ground level

    He emphasises that the Higgs is much more than the final item on the Standard Model checklist; there is a great deal still to find out about it. “It’s like a new wrench that we still have to work out exactly where to fit.” Prof Shears agrees: “We’ve only had about a thousand or two of these new particles, to try and understand their nature.

    “And although it looks like the Higgs boson that we expect from our theory, there’s still a chance that it might have partners that would then tell us that we’re not looking at our normal theory at all. We’re looking at something deeper and more exotic.”

    That is the central impatience that is itching all the physicists here: they want to find something that falls completely outside what they expect or understand. “The data so far has confirmed that our theory is really really good, which is frustrating because we know it’s not!” Prof Shears says. “We know it can’t explain a lot of the Universe.

    “So instead of trying to test the truth of this theory, what we really want to do now is break it – to show where it stops reflecting reality. That’s the only way we’re going to make progress.”

    In the canteen at Cern headquarters I meet Dr Steven Goldfarb, a physicist and software developer on the Atlas team. His sentiments are similar. “We have a fantastic model – that we hate,” he chuckles. “It has stood up to precision measurements for 50 years. We get more and more precise, and it stands up and stands up. But we hate it, because it doesn’t explain the universe.”

    6

    Dark matter: present but invisible

    In fact, only about 5% of the universe is accounted for by the Standard Model. Physicists think that the rest is made up of dark energy (70%) and dark matter (25%) – but these are still just proposals without any experimental evidence. Based on how fast galaxies move and spin, we know there is much more stuff in the universe than what we can see with telescopes. One idea for a “new physics” that might allow for more particles, including the mysterious constituents of dark matter, is supersymmetry.

    Supersymmetry standard model
    Standard Model of Supersymmetry

    It has also never been glimpsed in data from the LHC or elsewhere, but remains a popular concept with theorists. Supersymmetry suggests that all the particles we know about have heavier, “super” partners – as yet unseen by science.

    That failure doesn’t faze the theory’s fans, Dr Golfarb explains. “If you say to someone who really likes supersymmetry, ‘Hey, why haven’t we found any of the particles yet?’ they’ll say, ‘We’ve found half of the particles! We just need to find the other half…'”

    7
    8
    The Standard Model equation is etched in stone outside Cern’s control room – but physicists inside want to find something it can’t explain

    Some of those missing, hypothetical particles – notably the gluino and the neutralino – have been mooted as the most likely first results from LHC Run Two.

    They also make promising candidate building blocks for dark matter. But the researchers are open to other possibilities. Dr Goldfarb says the search need not focus on specific, ghostly particles: “It doesn’t have to be supersymmetry. You can also just look for dark matter. That’s why we build our detectors perfectly hermetically.”

    CMS and Atlas are the two “general-purpose” experiments at the LHC. Both of them have detectors completely surrounding the collision point, so that nothing can escape.

    Well, almost nothing. “You can’t build a neutrino detector – so neutrinos do get out. But we know under what circumstances and how often there ought to be neutrinos. So we can account for the missing energy.” What the team really wants to see is a chunk of missing energy that they categorically cannot account for. “When you see a lot of missing momentum – more than is predicted in standard model – then you may have found a candidate for dark matter,” Dr Goldfarb explains.

    9

    Antimatter: missing altogether

    Even within the 5% of the universe that we do know about, there is a baffling imbalance. The Big Bang ought to have produced two flavours of particle – matter and antimatter – in equal amounts. When those two types of particle collide, they “annihilate” each other. A lot of that sort of annihilation went on, physicists say, and everything we can see in the universe is just the scraps left behind. But puzzlingly, nearly all of those scraps are of one flavour: matter.

    “You just don’t get antimatter in the universe,” says Prof Shears. “You get it in sci-fi and you get it when things decay radioactively, but there are no good deposits of it around.” This glaring absence is “one of the biggest mysteries we have”, she adds. And it is the primary target of the LHCb experiment.

    There, a series of slab-shaped detectors is waiting to try and pinpoint the difference between the particles and anti-particles that pop out of the proton collisions. Run One did reveal some of those differences – but nothing that could explain the drastic tipping of the universal scales towards matter.

    9
    10
    The beam pipe runs directly through the middle of the huge, slab-shaped detectors at LHCb

    “We think now that the answer has to lie in some new physics,” says Prof Shears. She hopes the near doubling of the collision energy will offer a peek. “We’ve got a million crazy ideas. All we can do is to keep our options open, to sift through the data – and to look for the unexpected.”

    Gravity gap

    There are other questions, too. Gravity, somewhat alarmingly, is nowhere to be found in the Standard Model. “There’s no gravity on that mug,” says Dr Goldfarb, pointing to an LHC souvenir with the model’s equation emblazoned on its side. “That’s annoying! But there’s no answer in sight.” And there is always the ongoing quest to smash the things we currently think are the smallest in existence, and find smaller ones. Dr Goldfarb calls this “the oldest physics” and imagines a cavewoman – the first physicist – banging rocks together to see what was inside.

    12
    Final touches at CMS: ‘It’s like you’ve put a ship in the harbour and replaced every single plank’ “We’re still doing that today, and we still wonder what’s inside,” he says. “There’s nothing that discounts the idea that electrons, or quarks, are made up of something else. We just call them fundamental because as far as we know, they are.”

    The extra power in Run Two might produce just this kind of fundamental fruit. “The more energy we have for these collisions, the smaller the bits that we can look at,” says Dr David.

    “The ultimate goal here is to understand what matter is made of.” And the world’s largest laboratory is not just repaired, but renewed and ready for that goal. “It’s like you’ve put a ship in the harbour and replaced every single plank,” Dr David says with pride. “It’s not the same ship. It’s a whole new ship and it’s going on a new adventure.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 4:10 pm on February 17, 2015 Permalink | Reply
    Tags: , , CERN LHC, , ,   

    From AAAS: “Five things scientists could learn with their new, improved particle accelerator” 

    AAAS

    AAAS

    15 February
    Emily Conover

    1
    CMS

    The Large Hadron Collider (LHC) is back, and it’s better than ever.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC

    The particle accelerator, located at CERN, the European particle physics lab near Geneva, Switzerland, shut down in February 2013, and since then scientists have been upgrading and repairing it and its particle detectors. The LHC will be back up to full speed this May. Yesterday, scientists discussed the new prospects for the LHC at the annual meeting of AAAS (which publishes Science).

    The LHC is the world’s most powerful particle accelerator. Protons blast along its 17-mile (27-kilometer) ring at nearly light speed, colliding at the sites of several particle detectors, which sift through the resulting particle debris. In 2012, LHC’s ATLAS and CMS experiments discovered the Higgs boson with data from the LHC’s first run, thereby explaining how particles get mass.

    CERN ATLAS New
    ATLAS

    CERN CMS New
    CMS

    The revamped LHC will run at a 60% higher energy, with more sensitive detectors, and a higher collision rate. What might we find with the new-and-improved machine? Here are five questions scientists hope to answer:

    1. Does the Higgs boson hold any surprises?

    Now that we’ve found the Higgs boson, there’s still a lot we can learn from it. Thanks to the LHC’s energy boost, it will produce Higgs bosons at a rate five times higher, and scientists will be using the resulting abundance of Higgs to understand the particle in detail. How does it decay? Does it match the theoretical predictions? Anything out of the ordinary would be a boon to physicists, who are looking for evidence of new phenomena that can explain some of the unsolved mysteries of physics.

    2. What is “dark matter”?

    Only 15% of the matter in the universe is the kind we are familiar with. The rest is dark matter, which is invisible to us except for subtle hints, like its gravitational effects on the cosmos. Physicists are clamoring to know what it is. One likely dark matter culprit is a WIMP, or weakly interacting massive particle, which could show up in the LHC. Dark matter’s fingerprints could even be found on the Higgs boson, which may sometimes decay to dark matter. You can bet that scientists will be sifting through their data for any trace.

    3. Will we ever find supersymmetry?

    Supersymmetry, or SUSY, is a hugely popular theory of particle physics that would solve many unanswered questions about physics, including why the mass of the Higgs boson is lighter than naively expected—if only it were true. This theory proposes a slew of exotic elementary particles that are heavier twins of known ones, but with different spin—a type of intrinsic rotational momentum. Higher energies at the new LHC could boost the production of hypothetical supersymmetric particles called gluinos by a factor of 60, increasing the odds of finding it.

    Supersymmetry standard model
    Standard Model of Supersymmetric particles

    4. Where did all the antimatter go?

    Physicists don’t know why we exist. According to theory, after the big bang the universe was equal parts matter and antimatter, which annihilate one another when they meet. This should have eventually resulted in a lifeless universe devoid of matter. But instead, our universe is full of matter, and antimatter is rare—somehow, the balance between matter and antimatter tipped. With the upgraded LHC, experiments will be able to precisely test how matter might differ from antimatter, and how our universe came to be.

    5. What was our infant universe like?

    Just after the big bang, our universe was so hot and dense that protons and neutrons couldn’t form, and the particles that make them up—quarks and gluons—floated in a soup known as the quark-gluon plasma. To study this type of matter, the LHC produces extra-violent collisions using lead nuclei instead of protons, recreating the fireball of the primordial universe. Aided by the new LHC’s higher rate of collisions, scientists will be able to take more baby photos of our universe than ever before.

    See the full article here.

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

    Please help promote STEM in your local schools.
    STEM Icon
    Stem Education Coalition

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
Follow

Get every new post delivered to your Inbox.

Join 446 other followers

%d bloggers like this: