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  • richardmitnick 3:21 pm on April 10, 2016 Permalink | Reply
    Tags: , , , , Particle Accelerators, ,   

    From The Daily Galaxy: “CERN LHC Reveals: “The Universe a Billionth of a Second After the Big Bang” 

    Daily Galaxy
    The Daily Galaxy

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

    April 09, 2016
    No writer credit found

    “It is remarkable that we are able to carry out such detailed measurements on a drop of ‘early universe’, that only has a radius of about one millionth of a billionth of a meter. The results are fully consistent with the physical laws of hydrodynamics, i.e. the theory of flowing liquids and it shows that the quark-gluon plasma behaves like a fluid.

    It is however a very special liquid, as it does not consist of molecules like water, but of the fundamental particles quarks and gluons,” explained Jens Jørgen Gaardhøje, professor and head of the ALICE group at the Niels Bohr Institute at the University of Copenhagen.

    A few billionths of a second after the Big Bang, the universe was made up of a kind of extremely hot and dense primordial soup of the most fundamental particles, especially quarks and gluons. This state is called quark-gluon plasma. By colliding lead nuclei at a record-high energy of 5.02 TeV in the world’s most powerful particle accelerator, the 27 km long Large Hadron Collider, LHC at CERN in Geneva, it has been possible to recreate this state in the ALICE experiment’s detector and measure its properties.

    Quark gluon plasma. Duke University
    Quark-gluon plasma. Duke University

    CERN researchers recreated the universe’s primordial soup in miniature format by colliding lead atoms with extremely high energy in the 27 km long particle accelerator, the LHC in Geneva. The primordial soup is a so-called quark-gluon plasma and researchers from the Niels Bohr Institute, among others, have measured its liquid properties with great accuracy at the LHC’s top energy. The results were submitted to Physical Review Letters, which is the top scientific journal for nuclear and particle physics.

    “The analyses of the collisions make it possible, for the first time, to measure the precise characteristics of a quark-gluon plasma at the highest energy ever and to determine how it flows,” explains You Zhou, who is a postdoc in the ALICE research group at the Niels Bohr Institute.

    CERN ALICE Icon HUGE
    ALICE Run Control Center
    CERN ALICE New
    CERN ALICE New II
    CERN ALICE and the Control Room

    You Zhou, together with a small, fast-working team of international collaboration partners, led the analysis of the new data and measured how the quark-gluon plasma flows and fluctuates after it is formed by the collisions between lead ions.

    The focus has been on the quark-gluon plasma’s collective properties, which show that this state of matter behaves more like a liquid than a gas, even at the very highest energy densities. The new measurements, which uses new methods to study the correlation between many particles, make it possible to determine the viscosity of this exotic fluid with great precision.

    You Zhou explains that the experimental method is very advanced and is based on the fact that when two spherical atomic nuclei are shot at each other and hit each other a bit off center, a quark-gluon plasma is formed with a slightly elongated shape somewhat like an American football. This means that the pressure difference between the centre of this extremely hot ‘droplet’ and the surface varies along the different axes. The pressure differential drives the expansion and flow and consequently one can measure a characteristic variation in the number of particles produced in the collisions as a function of the angle.

    Jens Jørgen Gaardhøje adds that they are now in the process of mapping this state with ever increasing precision — and even further back in time.

    See the full article here .

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  • richardmitnick 3:37 pm on April 8, 2016 Permalink | Reply
    Tags: , , , , , , Particle Accelerators,   

    From FNAL: “Heavy neutrinos: Leave no stone unturned” 

    FNAL II photo

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

    April 8, 2016
    Bo Jayatilaka

    While the discovery of the Higgs boson at the LHC yielded considerable evidence that the Higgs mechanism is responsible for some particles having mass and others not, it does not help explain why massive particles have the specific masses they do. Over a decade prior to the discovery of the Higgs boson, experiments studying neutrinos produced by the sun and by particle accelerators made the astounding discovery that neutrinos have mass, albeit in incredibly tiny amounts. The question du jour about neutrino masses shifted immediately from “Do neutrinos have mass?” to “Why are neutrino masses what they are?”

    Physicists naturally attack this question from as many angles as possible. A significant focus of the scientific efforts of Fermilab center on studying neutrinos produced by the Fermilab accelerator complex in order to probe this question. An experiment like CMS, designed to measure highly interactive particles, can’t directly detect neutrinos at all and might seem to be left on the sidelines in this quest. However, a popular family of theories suggests that there is an additional family of neutrino linked to the garden-variety neutrinos we know of. This linking mechanism between the known neutrinos and their exotic cousins is known as a “seesaw mechanism,” as it forces one type to become massive when the others become lightweight. Searching for unknown but massive particles is exactly what the CMS detector was designed to do.

    CERN/CMS Detector
    CERN/CMS Detector

    The CMS experiment has searched for such heavy neutrinos, focusing on the case where the heavy neutrino is of the Majorana type, meaning that it is its own antiparticle. As Don Lincoln explains about one of the first such searches, the production and decay of a heavy Majorana neutrino results in the signature of two leptons (electrons or muons) of the same electric charge along with jets. A more recent search at CMS used the full 8-TeV data set and focused on events in which the same-charged leptons were muons.

    To ensure that no stone remains unturned in the search for heavy Majorana neutrinos, the analysis of 8-TeV data has been updated* to include events with like-charged electron pairs and like-charged pairings of an electron and a muon.-

    Unfortunately, as with the previous searches, no evidence of a heavy neutrino was seen. However, the inclusion of electron and electron-muon pair events allowed CMS physicists to place significantly more stringent limits on the possible masses of heavy Majorana neutrinos. With Run 2 of the LHC under way, you can expect searches for Majorana neutrinos to push into ever higher masses.

    *Search for heavy Majorana neutrinos in e+/- e+/- plus jets and e+/- mu+/- plus jets events in proton-proton collisions at sqrt(s) = 8 TeV
    CMS Collaboration

    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 3:23 pm on April 7, 2016 Permalink | Reply
    Tags: , , , , , , , Particle Accelerators, ,   

    From Symmetry: “Physicists build ultra-powerful accelerator magnet” 

    Symmetry Mag

    Symmetry

    04/07/16
    Sarah Charley

    Magnet built for LHC

    The next generation of cutting-edge accelerator magnets is no longer just an idea. Recent tests revealed that the United States and CERN have successfully co-created a prototype superconducting accelerator magnet that is much more powerful than those currently inside the Large Hadron Collider.

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

    Engineers will incorporate more than 20 magnets similar to this model into the next iteration of the LHC, which will take the stage in 2026 and increase the LHC’s luminosity by a factor of ten. That translates into a ten-fold increase in the data rate.

    “Building this magnet prototype was truly an international effort,” says Lucio Rossi, the head of the High-Luminosity (HighLumi) LHC project at CERN. “Half the magnetic coils inside the prototype were produced at CERN, and half at laboratories in the United States.”

    During the original construction of the Large Hadron Collider, US Department of Energy national laboratories foresaw the future need for stronger LHC magnets and created the LHC Accelerator Research Program (LARP): an R&D program committed to developing new accelerator technology for future LHC upgrades.

    MQXF1 quadrupole 1.5-meter prototype magnet sits at Fermilab before testing.
    MQXF1 quadrupole 1.5-meter prototype magnet sits at Fermilab before testing. G. Ambrosio (US-LARP and Fermilab), P. Ferracin and E. Todesco (CERN TE-MSC)

    This 1.5-meter-long model, which is a fully functioning accelerator magnet, was developed by scientists and engineers at Fermilab [FNAL], Brookhaven National Laboratory [BNL], Lawrence Berkeley National Laboratory [LBL], and CERN.

    FNAL II photo
    FNAL

    BNL Logo (2)
    BNL

    LBL Big
    LBL

    CERN
    CERN

    The magnet recently underwent an intense testing program at Fermilab, which it passed in March with flying colors. It will now undergo a rigorous series of endurance and stress tests to simulate the arduous conditions inside a particle accelerator.

    This new type of magnet will replace about 5 percent of the LHC’s focusing and steering magnets when the accelerator is converted into the High-Luminosity LHC, a planned upgrade which will increase the number and density of protons packed inside the accelerator. The HL-LHC upgrade will enable scientists to collect data at a much faster rate.

    The LHC’s magnets are made by repeatedly winding a superconducting cable into long coils. These coils are then installed on all sides of the beam pipe and encased inside a superfluid helium cryogenic system. When cooled to 1.9 Kelvin, the coils can carry a huge amount of electrical current with zero electrical resistance. By modulating the amount of current running through the coils, engineers can manipulate the strength and quality of the resulting magnetic field and control the particles inside the accelerator.

    The magnets currently inside the LHC are made from niobium titanium, a superconductor that can operate inside a magnetic field of up to 10 teslas before losing its superconducting properties. This new magnet is made from niobium-three tin (Nb3Sn), a superconductor capable of carrying current through a magnetic field of up to 20 teslas.

    “We’re dealing with a new technology that can achieve far beyond what was possible when the LHC was first constructed,” says Giorgio Apollinari, Fermilab scientist and Director of US LARP. “This new magnet technology will make the HL-LHC project possible and empower physicists to think about future applications of this technology in the field of accelerators.”

    High-Luminosity LHC coil
    High-Luminosity LHC coil similar to those incorporated into the successful magnet prototype shows the collaboration between CERN and the LHC Accelerator Research Program, LARP.
    Photo by Reidar Hahn, Fermilab

    This technology is powerful and versatile—like upgrading from a moped to a motorcycle. But this new super material doesn’t come without its drawbacks.

    “Niobium-three tin is much more complicated to work with than niobium titanium,” says Peter Wanderer, head of the Superconducting Magnet Division at Brookhaven National Lab. “It doesn’t become a superconductor until it is baked at 650 degrees Celsius. This heat-treatment changes the material’s atomic structure and it becomes almost as brittle as ceramic.”

    Building a moose-sized magnet from a material more fragile than a teacup is not an easy endeavor. Scientists and engineers at the US national laboratories spent 10 years designing and perfecting a new and internationally reproducible process to wind, form, bake and stabilize the coils.

    “The LARP-CERN collaboration works closely on all aspects of the design, fabrication and testing of the magnets,” says Soren Prestemon of the Berkeley Center for Magnet Technology at Berkeley Lab. “The success is a testament to the seamless nature of the collaboration, the level of expertise of the teams involved, and the ownership shown by the participating laboratories.”

    This model is a huge success for the engineers and scientists involved. But it is only the first step toward building the next big supercollider.

    “This test showed that it is possible,” Apollinari says. “The next step is it to apply everything we’ve learned moving from this prototype into bigger and bigger magnets.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 1:05 pm on April 6, 2016 Permalink | Reply
    Tags: , , , , , Particle Accelerators,   

    From CERN: “LINAC4 ready to go up in energy” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    4.6.16
    Jennifer Toes

    1
    The DTL section of the LINAC4 (Image: CERN)

    The LINAC4 linear accelerator has recently achieved beam commissioning of 50MeV and is now almost ready for the next step of increasing the beam energy even further up to 100MeV. This project is part of the LHC Injectors Upgrade (LIU) required for the needs of the High Luminosity LHC (HL-LHC).

    LINAC4 aims to replace the ageing LINAC2 linear accelerator, going from the present 50 MeV proton beam injection into the Proton Synchrotron Booster (PSB), the first ring in the CERN accelerator chain, to a modern H- ion beam injection at 160 MeV, more the three times the Linac2 energy.

    “CERN is one of the few laboratories in the world that has not yet implemented H- injection” said Alessandra Lombardi, who is responsible for the beam commissioning of the LINAC4. Injecting H- at a higher energy results in a smaller emittance in the PSB.

    Following the successful commissioning of the three newly designed Drift Tube Linac (DTL) tanks in November 2015, the team began its preparations for the installation of two key accelerating sectors: the Cell Coupled Drift Tube Linac (CCDTL) and PI-Mode Structures (PIMS).

    Built in Russia by a collaboration of CERN with two Russian laboratories, VNIITF in Snezinsk and BINP in Novossibirsk, the CCDTL is the next structure to be conditioned and commissioned with beam in the LINAC4.

    “The CERN CCDTL is composed of 7 modules of 3 tanklets each and it brings the energy of the beam from 50 to 100MeV” said Lombardi.

    The main advantage of CCDTLs over standard DTLs is that their quadrupoles are external and therefore more accessible. The accessibility of these magnets makes the construction and alignment process much more straight forward.

    The PIMS was constructed as part of a CERN-Poland (NCBJ Swierk) collaboration with contributions from FZ Jülich (Germany). The PIMS was assembled and tuned at CERN will bring up the beam energy from 100MeV to its final goal of 160MeV. It is composed of 12 modules for a total length of about 25m.

    Currently, the installation and conditioning of all CCDTL tanks and of the first PIMS is being carried out before beam commissioning begins on April 11th 2016. The commissioning of the remaining PIMS tanks expected to follow in October will allow reaching the final beam energy.

    Scheduled to become operational by 2020, the LINAC4 is a crucial step towards the increase in the LHC luminosity that will allow CERN to remain at the pinnacle of high energy physics research.

    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 II

    LHC

    CERN LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

     
  • richardmitnick 12:28 pm on April 1, 2016 Permalink | Reply
    Tags: , , , KEK Belle II, Particle Accelerators, ,   

    From Symmetry: “Belle II and the matter of antimatter” 

    Symmetry Mag
    Symmetry

    04/01/16
    Matthew R. Francis

    DESY Belle II detector
    DESY Belle II detector

    Go inside the new detector looking for why we’re here.

    We live in a world full of matter: stars made of matter, planets made of matter, pizza made of matter. But why is there pizza made of matter rather than pizza made of antimatter or, indeed, no pizza at all?

    In the first split-second after the big bang, the universe made a smidgen more matter than antimatter. Instead of matter and antimatter annihilating one another and leaving an empty, cold universe, we ended up with a surplus of stuff. Now scientists need the most sensitive detectors and mountains of experimental data to understand where that imbalance comes from.

    Belle II is one of those detectors that will look for differences between matter and antimatter to explain why we’re here at all. Currently under construction, the 7.5-meter-long detector will be installed in the newly recommissioned SuperKEKB particle accelerator located in Tsukuba, Japan.

    SuperKEKB accelerator Japan
    SuperKEKB accelerator Japan

    SuperKEKB runs beams of electrons and positrons (the antimatter version of electrons) into each other at close to the speed of light, and Belle II—once it is fully operational in 2018—will analyze the detritus of the collisions.

    “All the experimental results to this point have been consistent with the so-called Standard Model of particle physics,” says Tom Browder, a physicist at the University of Hawaii and one of the spokespeople for the project.

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

    But while the Standard Model allows for some asymmetry, it doesn’t explain the matter-antimatter imbalance that exists. We need something more.

    Belle II will look for the signatures of new physics in the rare decays of bottom quarks, charm quarks and tau leptons. (Bottom quarks are also known as beauty quarks, which is the “B” in SuperKEKB; the name “Belle” itself refers to “beauty”). Bottom and charm quarks are massive compared with the up and down quarks that make up ordinary matter, while tau leptons are the much heavier cousins of electrons. All three particles are unstable, decaying into a variety of lower-mass particles. If Belle II researchers spot a difference in the decays of these particles and their antimatter counterparts, it could explain why we ended up in a cosmos full of matter.

    Finding the beauty is a beast

    When electrons and positrons collide at low energy, they annihilate and convert all of their mass into gamma rays. At very high speed, however, the extra energy produces pairs of matter and antimatter particles, all of which are more massive than the original electrons. SuperKEKB smashes electrons and positrons together with the right energy to make B-mesons, particles made of a bottom quark and an antimatter quark of another type, along with anti-B-mesons, made of a bottom anti-quark and a matter quark.

    These mesons change into other particles in complex ways as the bottom quarks and antiquarks decay. Belle II’s detectors will try to find decays that either aren’t allowed by the Standard Model or happen more or less often than expected. Any such deviations could be signs of new physics. The detector can also help physicists better understand particles made of four or five quarks (tetraquarks and pentaquarks) or stuck-together “molecules” of quarks.

    “The cleaner environment at Belle II might make it easier to study some of those states, and to try to understand what the internal quark structure is,” says James Fast of the Department of Energy’s Pacific Northwest National Laboratory, lead lab for the US contributions to the Belle II detector upgrade.

    SuperKEKB collides electrons and positrons, which aren’t made of anything smaller. This results in a clean collision. And because the energy going into each collision at SuperKEKB is well known, Belle II can study decays with invisible particles such as neutrinos by looking for the missing energy they carry away.

    “The cleanliness of data at SuperKEKB enables the majority of B[-meson] events to be recorded,” says Kay Kinoshita of the University of Cincinnati, who works on the software Belle II will use to analyze collisions.

    But Belle II isn’t the only detector searching for these rare bottom quark decays. An experiment at the LHC, LHCb, is also on the hunt.

    CERN LHC LHCb
    CERN LHC LHCb

    The LHC produces a wider variety of particles containing bottom quarks. That includes a type that decays into two muons, “which is a ‘golden’ mode for effects from supersymmetry and theories with multiple Higgs bosons,” says Harry Cliff, a physicist at the University of Cambridge who works on LHCb.

    Race to the bottom

    Belle II is the aptly named successor to the Belle experiment and is designed to handle as much as 50 times the number of collisions in the previous design. It’s a monumental effort involving hundreds of physicists and engineers from 23 nations in Asia, Europe and North America.

    “The amount of data that Belle II will collect can be comparable to data management challenges that are faced by the big LHC experiments [like CMS and ATLAS],” says Fast.

    CERN CMS Detector
    CERN CMS Detector

    CERN/ATLAS
    CERN/ATLAS

    Universities don’t have the resources to operate the computers needed to manage all the data coming from Belle II, so a national lab like PNNL is an ideal host. Similar data centers for Belle II will operate in Japan and Europe.

    At present, the SuperKEKB accelerator is successfully storing both electrons and positrons to prepare for the tests that will lead to new experiments. The Belle II assembly will be in place next year, followed by a commissioning process to make sure everything is working properly. In 2018, the full experiment will be operational and producing data to find exotic B-meson behavior.

    It may feel ironic to take years to recreate what the universe did in a split second, but such is the nature of particle physics. The process of smashing electrons and positrons together isn’t identical to the process that created the early cosmos either, but if there’s any new physics hiding in the decays of bottom quarks, this is the type of experiment that could find it. Which is, after all, the beauty of science.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 3:56 pm on March 29, 2016 Permalink | Reply
    Tags: , , , Particle Accelerators, ,   

    From Ethan Siegel: “What it means if CERN discovers a new particle” 

    Starts with a bang
    Starts with a Bang

    3.29.16
    Ethan Siegel

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN
    CERN/ATLAS
    CERN ATLAS Higgs Event
    ATLAS
    CERN CMS Detector
    CERN CMS Higgs Event
    CMS
    CERN/ALICE Detector
    ALICE
    CERN/LHCb
    LHCb

    There’s been a small but significant excess observed [1.6 σ], and a new particle is one possible explanation. What will it mean?

    “I’m a fan of supersymmetry, largely because it seems to be the only route by which gravity can be brought into the scheme. It’s probably not even enough, but it’s a way forward to get gravity involved. If you have supersymmetry, then there are more of these particles. That would be my favourite outcome.” –Peter Higgs

    In the 1960s and 1970s, the finishing theoretical touches were being put on the Standard Model of elementary particle physics.

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

    Inside the world of the atom were subatomic, fundamental particles, including electrons, two types of quarks and the gluons. In addition, over time, a whole slew of other particles were discovered:

    a total of six types of quarks and their corresponding antiparticles (antiquarks), each coming in three colors (or anticolors),
    three charged leptons and three neutral, low-mass neutrinos, each with their own antiparticles,
    and the bosons: the photon (for the electromagnetic force), the eight gluons (for the strong nuclear force), the W+, W- and the Z (for the weak force), plus the Higgs boson.

    1
    Image credit: E. Siegel, from his book, Beyond The Galaxy.

    It took 50 years from the time this model was set into place for the entire set to be discovered. The culmination of the Standard model was the discovery of the Higgs boson: earlier this decade at the Large Hadron Collider at CERN. But in that time, there were a whole slew of other mysteries that came about, mysteries that — by their very nature — require the existence of new particles to explain the physics we observed. They include:

    dark matter, or the fact that some 80–85% of the mass of the Universe cannot be accounted for by the particles in the Standard Model.
    neutrino masses, which should have been zero, but instead are tiny (millions of times lighter than the electron) and non-zero, and require a new particle to explain their existence.
    the matter-antimatter asymmetry, which cannot be explained by the known particles and interactions alone, and require new physics — particles and interactions — to account for what our Universe gives us.

    3
    One possible set of new particles that could give rise to the matter-antimatter asymmetry. Image credit: E. Siegel, from his book, Beyond The Galaxy.

    Many different scenarios exist that could explain these phenomena through the existence of new particles, but a few of the more interesting ones include supersymmetry, extra dimensions and technicolor extensions. Why are these, among others, interesting? Because if they are correct, they should give rise to new fundamental particles, particle beyond the Standard Model, that the LHC might see!

    Standard model of Supersymmetry Illustration: CERN & IES de SAR
    Standard model of Supersymmetry Illustration: CERN & IES de SAR

    Supersymmetry, for instance, predicts the existence — in all its forms — of at least one (and in most models, four) additional, heavy, Higgs-like particles. The way to discover a particle like this is to calculate, at all energies, what the expected contributions are from all the known particles to various decay pathways (two photons, two charged leptons, a W+ and W- boson, etc.), and then make the observations and look for differences.

    If you find significant enough differences in the right places, you’ll discover a new particle. This is how, in the past, we’ve discovered particles like the Z, the top quark and the Higgs.

    4
    Image credit: the LEP collaboration and various sub-collaborations, 2005, via http://arxiv.org/abs/hep-ex/0509008. Precision Electroweak Measurements on the Z Resonance. Note that the Z-particle appears with a “width” in energy.

    In December, the ATLAS collaboration announced that it appeared they had seen a little bit of evidence — not enough to claim discovery, but enough that it looked like it might not just be noise — of a new particle around 750 GeV in energy, or about five times the mass of the Higgs boson. It was consistent, they said, with another spin-0 particle, meaning that it might be another Higgs! At the same time, the CMS collaboration saw something very similar, although it was consistent with a spin-2 particle.

    As of last week, both collaborations have now taken the full suite of data currently available, and have come together (although with independent results) to compare.

    5
    The new signal at 750 GeV, via both the CMS and ATLAS collaborations. Image credit: Pauline Gagnon, via http://www.quantumdiaries.org/2016/03/18/two-steps-closer-to-a-possible-discovery/.

    Before you go getting all excited, realize the following: this might turn out to be nothing! Sure, there’s something fishy going on in this 750 GeV energy range, but the statistics up there are very limited right now. There’s a very good reason that particle physicists don’t claim discoveries of new particles until a certain standard (5σ significance) is reached: the dustbin of history is littered with “discoveries” that turned out to be mere fluctuations in the data that went away with more and better data. That could be exactly what we’re looking at here.

    The beautiful part of this is that we won’t have to wait forever. The LHC restarts at its highest energies and highest luminosities (i.e., the greatest numbers of collisions-per-second) ever this May, and by time mid-summer rolls around, we should know whether this is a true particle or merely a fluctuation. If it is a new particle, we’ll have our first direct hint of what lies beyond the Standard Model, and a new era in physics will be ushered in. But if it turns out to be a fluctuation — and if you’re a betting person, you’d be smart to bet on the fluctuation answer — it’s back to the drawing board for model-builders. The secrets of nature may turn out to be more elusive than physicists have imagined thus far.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
  • richardmitnick 9:52 am on March 25, 2016 Permalink | Reply
    Tags: , , , , Particle Accelerators,   

    From LHC/ATLAS at CERN: “Spring awakening for the ATLAS experiment” 

    CERN ATLAS Higgs Event

    CERN/ATLAS
    ATLAS

    24th March 2016
    Katarina Anthony

    This morning the Large Hadron Collider (LHC) circulated the first proton-proton beams of 2016 around its 27 kilometre circumference. The beams were met with great enthusiasm in the ATLAS Control Centre as they passed through the ATLAS experiment.

    These beams mark the start of an exciting new period for ATLAS and other CERN experiments. Having seen tantalising but still inconclusive signals in 2015, ATLAS physicists around the world are eagerly awaiting new data to analyse.

    The start of a new run also means the conclusion of a maintenance period, known as the Year-End-Technical-Stop (YETS). This 3 month-long upkeep is vital for the health and well-being of the detectors, ensuring that ATLAS can function impeccably for the 9 straight months of operation that follow.

    1
    ATLAS uses “beam splash” events to provide simultaneous signals to large parts of the detector, and verify that the readout of different detectors elements are fully synchronized. (Image: ATLAS Experiment © 2016 CERN)

    “This is a normal period of maintenance that happens yearly,” says Michel Raymond, ATLAS Deputy Technical Coordinator. “At ATLAS we use this time to repair and consolidate the detectors first, but also all the infrastructure around that allows us to run the detector.”

    But before their work can begin, there is a lot preparation needed. Although located in an enormous 52,500 m3 cavern, the ATLAS experiment fills that space nearly to the brink. Whatever room is left over is devoted to the cabling and cooling infrastructure that keeps the experiment running. “You cannot just go in and start working on a detector element,” says Raymond. “We first need to move the shielding and cabling to get the experiment into a configuration where the requested detector is accessible.”

    Moving these elements is called “opening” the detector and can take at least 3 weeks. The ATLAS teams have to go slowly and carefully, as they are moving fragile equipment that can weigh anywhere between 100 to 1000 tonnes.

    Once the detector elements are accessible, the teams have only a few weeks to get to work before they need to start closing the detector back up. “Every hour in the cavern is precious,” says Raymond. “We prioritise in advance what operations are the most important, and which can wait for next maintenance period.

    2
    This display shows one of the ATLAS Experiment’s first splashes on 2016, with beam 1 at 10:26 a.m. on Friday 25th March 2016. (Image: ATLAS Experiment © 2016 CERN)

    During this YETS period, the main priority was the repair of ATLAS’ end-cap magnet bellows. These bellows protect the integrity of the vacuum surrounding ATLAS cooling elements, and are essential for keeping the magnet system cool. They were damaged during a previous maintenance period though continued to work adequately throughout 2015. The damage was successfully repaired during this recent shutdown.

    “After that, we took action on the detector elements, repairing wear-and-tear damage,” says Raymond. “There was a lot of work needed on the muon chambers and the Tile Calorimeters, replacing faulty electronic elements; and a number of gas connections had to be replaced on both sides of the experiment, to avoid leaks.”

    With the work now complete and beams running through the LHC, most of the ATLAS Collaboration has turned their focus to the data. However Michel and his colleagues continue to look forward to their next trip underground. “We’re always planning ahead, thinking about the next shutdown and the ones after that,” concludes Raymond.

    See the full article here .

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

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  • richardmitnick 5:56 pm on March 18, 2016 Permalink | Reply
    Tags: , , , , Particle Accelerators,   

    From CERN: “Another important step for the AWAKE experiment” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    By harnessing the power of wakefields generated by a proton beam in a plasma cell, the AWAKE experiment at CERN (CERN Courier November 2013 p17) aims to produce accelerator gradients that are hundreds of times higher than those achieved in current machines.

    CERN Awake schematic
    CERN Awake schematic

    The experiment is being installed in the tunnel that was previously used by the CERN Neutrinos to Gran Sasso facility. In AWAKE, a beam of 400 GeV protons from the CERN Super Protron Synchrotron will travel through a plasma cell and will generate a wakefield that, in turn, will accelerate an externally injected electron beam.

    CERN  Super Proton Synchrotron
    Super Protron Synchrotron

    A laser will ionise the gas in the cell to become a plasma and seed the self-modulation instability that will trigger the wakefield. The project aims to prove that the plasma wakefield can be driven with protons and that its acceleration will be extremely powerful – hundreds of times more powerful than that achieved today – and eventually to provide a design for a plasma-based linear collider.

    The AWAKE tunnel is progressively being filled with its vital components. In its final configuration, the facility will feature a clean room for the laser, a dedicated area for the electron source and two new tunnels for two new beamlines: one small tunnel to hold the laser beam, which ionises the plasma and seeds the wakefields, and a second, larger tunnel that will be home to the electron beamline – the “witness beam” accelerated by the plasma. At the beginning of February, the plasma cell was lowered into the tunnel and moved to its position at the end of the proton line. The cell is a 10 m-long component developed by the Max Planck Institute for Physics in Munich (Germany). A first prototype successfully completed commissioning tests in CERN’s North Area in the autumn of 2015. The prototype allowed the AWAKE collaboration to validate the uniformity of the plasma temperature in the cell.

    AWAKE is a collaborative endeavour with institutes and organisations participating around the world. The synchronised proton, electron and laser beams provided by CERN are an integral part of the experiment. After installation of the plasma cell, the next step will be installation of the laser, the vacuum equipment and the diagnostic system for both laser and proton beams.

    Beam commissioning for the proton beamline is scheduled to start this summer. The programme will continue with installation of the electron line, with the aim of starting acceleration tests at the end of 2017.

    See the full article here.

    Please help promote STEM in your local schools.

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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 II

    LHC

    CERN LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

     
  • richardmitnick 5:35 pm on March 18, 2016 Permalink | Reply
    Tags: , , , , Particle Accelerators, ,   

    From CERN: “CMS hunts for supersymmetry in uncharted territory” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    Mar 18, 2016

    The CMS collaboration is continuing its hunt for signs of supersymmetry (SUSY), a popular extension to the Standard Model that could provide a weakly interacting massive-particle candidate for dark matter, if the lightest supersymmetric particle (LSP) is stable.

    Standard model of Supersymmetry Illustration: CERN & IES de SAR
    The Standard Model of Supersymmetry Illustration: CERN & IES de SAR

    With the increase in the LHC centre-of-mass energy from 8 to 13 TeV, the production cross-section for hypothetical SUSY partners rises; the first searches to benefit are those looking for the strongly coupled SUSY partners of the gluon (gluino) and quarks (squarks) that had the most stringent mass limits from Run 1 of the LHC. By decaying to a stable LSP, which does not interact in the detector and instead escapes, SUSY particles can leave a characteristic experimental signature of a large imbalance in transverse momentum.

    Searches for new physics based on final states with jets (a bundle of particles) and large transverse-momentum imbalance are sensitive to broad classes of new-physics models, including supersymmetry. CMS has searched for SUSY in this final state using a variable called the “stransverse mass”, MT2, to measure the transverse-momentum imbalance, which strongly suppresses fake contributions due to potential hadronic-jet mismeasurement. This allows us to control the background from copiously produced QCD multi-jet events. The remaining background comes from Standard Model processes such as W, Z and top-quark pair production with decays to neutrinos, which also produce a transverse-momentum imbalance. We estimate our backgrounds from orthogonal control samples in data targeted to each. To cover a wide variety of signatures, we categorise our signal events according to the number of jets, the number of jets arising from bottom quarks, the sum of the transverse momenta of hadronic jets (HT), and MT2. Some SUSY scenarios predict spectacular signatures, such as four top quarks and two LSPs, which would give large values for all of these quantities, while others with small mass splittings produce much softer signatures.

    Unfortunately, we did not observe any evidence for SUSY in the 2015 data set. Instead, we are able to significantly extend the constraints on the masses of SUSY partners beyond those from the LHC Run 1. The gluino has the largest production cross-section and many potential decay modes. If the gluino decays to the LSP and a pair of quarks, we exclude gluino masses up to 1550–1750 GeV, depending on the quark flavour, extending our Run 1 limits by more than 300 GeV. We are also sensitive to squarks, with our constraints summarised in figure 1. We set limits on bottom-squark masses up to 880 GeV, top squarks up to 800 GeV, and light-flavour squarks up to 600–1260 GeV, depending on how many states are degenerate in mass.

    Even though SUSY was not waiting for us around the corner at 13 TeV, we look forward to the 2016 run, where a large increase in luminosity gives us another chance at discovery.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

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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 II

    LHC

    CERN LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

     
  • richardmitnick 11:34 am on March 11, 2016 Permalink | Reply
    Tags: , , , , , Joel Butler, Particle Accelerators,   

    From Symmetry: “Fermilab scientist elected next CMS spokesperson” 

    Symmetry Mag

    Symmetry

    03/10/16
    Sarah Charley

    Joel Butler will lead the LHC experiment starting in September.

    CMS spokesman Joel Butler from FNAL
    Joel Butler

    Long before the start-up of the Large Hadron Collider, physicist Joel Butler was helping shape the path of particle physics research in the United States.

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

    He led experiments at the Department of Energy’s Fermilab, was one of the co-founders of the lab’s Computing Division, and served on the High Energy Physics Advisory Panel.

    Now, more than 30 years into his career as an experimental physicist, Butler’s responsibilities will become global as he takes the helm of one of the world’s largest physics experiments: the CMS experiment based at CERN.

    CERN CMS New
    CERN CMS Event
    CMS with possible Higgs event

    “I am very happy, but I also feel a great sense of responsibility,” Butler says. “It’s a huge collaboration and I am humbled that our collaborators trust me to lead them.”

    The CMS (Compact Muon Solenoid) collaboration designed, constructed and is currently operating one of the two LHC detectors that co-discovered the Higgs boson in 2012.

    Higgs Boson Event

    The CMS experiment is now searching at an even higher energy for phenomena beyond the Standard Model of particle physics, such as dark matter and new fundamental particles.

    Standard model with Higgs New
    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 collaboration consists of roughly 180 collaborating institutions and 3,000 scientists.

    As the spokesperson, Butler will be responsible for guiding the technical and scientific endeavors performed by universities and laboratories in more than 40 countries. He will also represent CMS in its interactions with other organizations and the public.

    Tiziano Camporesi is the current spokesperson of CMS experiment. He will lead the collaboration through the LHC’s spring start up and a summer of data collection before passing the baton to Butler in September 2016. He is looking forward to working with Butler through the challenges ahead.

    “We are all hoping to see some nice surprises from our data over the course of the next few years,” Camporesi says. “Butler is extremely hardworking and I’m confident he will do a good job leading the collaboration during this exciting time.”

    Butler joined the CMS collaboration in 2005. He oversaw the construction of the US-funded forward pixel detector and managed the US CMS Operations Program between 2007 and 2013. He is currently helping develop upgrades that will enable the CMS detector to handle higher collision rates in the future.

    During his term, Butler’s main goal is to understand the needs and abilities of CMS’s contributing institutions to maximize the scientific output of the CMS experiment and prepare the detector for the high-luminosity LHC run in 2020.

    “Different nations and institutes face different challenges,” Butler says. “We are going to take a huge amount of data and will have a big workload preparing the upgrades for the next generation of the LHC, which is why we need to increase our engagement with all of our collaborators to ensure that everyone is able to contribute effectively.”

    Even though Butler has spent nearly a third of his scientific career working on the CMS experiment, he admits that there is still a lot left to learn about the experiment and its collaborators.

    “I talked with nearly all of our institutions and explained plans, answered questions and discussed the experiment,” Butler says. “These meetings were incredibly valuable. No matter how much I think I know about CMS, there’s always a lot more to learn.”

    Butler’s term will start this fall and bring the CMS collaboration up to the end of LHC Run II in 2018, when the LHC will shut down for another round of upgrades before ramping up for Run III. Butler says he is looking forward to working with a large and diverse population of scientists at an important moment in physics history.

    “It’s a fantastic group of people, and my assignment is to help them all do the best job they can for CMS,” he says.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    Symmetry is a joint Fermilab/SLAC publication.


     
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