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  • richardmitnick 3:28 pm on February 21, 2018 Permalink | Reply
    Tags: , , , Particle Accelerators, , , Proton booster   

    From FNAL: “Fermilab’s Booster accelerator delivers record-setting proton beam” 

    FNAL II photo

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    FNAL Art Image by Angela Gonzales

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

    February 21, 2018
    Bill Pellico

    1
    This plot shows the ramp-up of proton flux in the Proton Source under PIP.

    FNAL booster

    On Jan. 29, Fermilab’s Booster accelerator achieved a record proton flux of 2.4×1017 protons per hour. This milestone achievement fulfills one of the most important requirements in the Proton Improvement Plan (PIP), which Fermilab has been implementing over the last five years.

    The main goal of the PIP project is to increase the proton beam output to meet Fermilab’s experimental needs, in particular for neutrino and muon experiments such as NOvA, MicroBooNE and Muon g-2. The Booster delivers beam to all of the lab’s experiments, and according to PIP, the Booster’s proton beam output, also known as proton flux, had to meet a certain minimum.

    FNAL NOvA Near Detector


    FNAL/NOvA experiment map

    FNAL/MicrobooNE

    FNAL Muon g-2 studio

    We delivered on that promise in January and have been operating the Booster at the new level since then. The record proton flux is about two-and-a-half times higher than what the accelerator was capable of delivering before the PIP upgrades, a flux of 1.1×1017. Now, with the Booster generating 2.4×1017 protons per hour at 15 hertz, the NuMI beamline, Booster Neutrino Beamline and the Muon Campus can all operate simultaneously. (Prior to this, we could operate only one at a time.)

    PIP started in 2012 to upgrade our aging Proton Source accelerators. Not only did we set out to increase the proton flux, we also aimed to provide a reliable source of protons for Fermilab’s scientific program. Reliability translates into “up time” — the fraction of time the accelerator is operating. PIP specified an up time of 85 percent, and we’ve exceeded that: We currently run at 92 percent up time, and we’re working to maintain this high performance level in the years to come.

    We could not have reached this milestone accelerator goal without the dedication of numerous people at the lab, who took on challenging engineering and beam physics problems and addressed other issues related to the viability and reliability of Fermilab’s Proton Source.

    It is truly remarkable that the Booster and the Linac — the oldest machines at the lab — are performing at record levels almost 50 years after they were first built, well higher than their design called for and beyond what anyone could have hoped for at the birth of the lab.

    Now we look to the next steps, working to achieve even higher proton flux levels. We’re also working to make sure PIP’s goal of providing a viable beam source until the successor plan, called PIP-II, is put in place. The PIP-II project will replace the current Linac with a new Superconducting Linac — in time for the operation of our flagship, LBNF/DUNE.

    The successful implementation of PIP ensures that the Proton Source can generate the beam needed to carry out Fermilab’s — and the nation’s — high-energy physics program. This was no small effort, and we congratulate and thank everyone involved for delivering world-class accelerators for fundamental science.

    See the full article here .

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

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  • richardmitnick 4:39 pm on February 20, 2018 Permalink | Reply
    Tags: "Rare hyperon-decay anomaly under the spotlight, , , , , , Particle Accelerators, ,   

    From CERN Courier: “Rare hyperon-decay anomaly under the spotlight” 


    CERN Courier

    Feb 16, 2018

    1
    The invariant mass distribution

    The LHCb collaboration has shed light on a long-standing anomaly in the very rare hyperon decay Σ+ → pµ+µ– first observed in 2005 by Fermilab’s HyperCP experiment. The HyperCP team found that the branching fraction for this process is consistent with Standard Model (SM) predictions, but that the three signal events observed exhibited an interesting feature: all muon pairs had invariant masses very close to each other, instead of following a scattered distribution.

    This suggested the existence of a new light particle, X0, with a mass of about 214 MeV/c2, which would be produced in the Σ+ decay along with the proton and would decay subsequently to two muons. Although this particle has been long sought in various other decays and at several experiments, no experiment other than HyperCP has so far been able to perform searches using the same Σ+ decay mode.

    The large rate of hyperon production in proton–proton collisions at the LHC has recently allowed the LHCb collaboration to search for the Σ+ → pµ+µ– decay. Given the modest transverse momentum of the final-state particles, the probability that such a decay is able to pass the LHCb trigger requirements is very small. Consequently, events where the trigger is activated by particles produced in the collisions other than those in the decay under study are also employed.

    This search was performed using the full Run 1 dataset, corresponding to an integrated luminosity of 3 fb–1 and about 1014 Σ+ hyperons. An excess of about 13 signal events is found with respect to the background-only expectation, with a significance of four standard deviations. The dimuon invariant- mass distribution of these events was examined and found to be consistent with the SM expectation, with no evidence of a cluster around 214  eV/c2. The signal yield was converted to a branching fraction of (2.1+1.6–1.2) × 10–8 using the known Σ+ → pπ0 decay as a normalisation channel, in excellent agreement with the SM prediction. When restricting the sample explicitly to the case of a decay with the putative X0 particle as an intermediate state, no excess was found. This sets an upper limit on the branching fraction at 9.5 × 10–9 at 90% CL, to be compared with the HyperCP result (3.1+2.4–1.9 ± 1.5) × 10–8.

    This result, together with the recent search for the rare decay KS → μ+μ– shows the potential of LHCb in performing challenging measurements with strange hadrons. As with a number of results in other areas reported recently, LHCb is demonstrating its power not only as a b-physics experiment but as a general-purpose one in the forward region. With current data, and in particular with the upgraded detector thanks to the software trigger from Run 3 onwards, LHCb will be the dominant experiment for the study of both hyperons and KS mesons, exploiting their rare decays to provide a new perspective in the quest for physics beyond the SM.

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  • richardmitnick 6:10 pm on February 13, 2018 Permalink | Reply
    Tags: , , , , Particle Accelerators, , , Supersymmetry (SUSY)   

    From CERN Courier: “ATLAS extends searches for natural supersymmetry” 


    CERN Courier

    Jan 15, 2018

    1
    Exclusion limits

    Despite many negative searches during the last decade and more, supersymmetry (SUSY) remains a popular extension of the Standard Model (SM). Not only can SUSY accommodate dark matter and gauge–force unification at high energy, it offers a natural explanation for why the Higgs boson is so light compared to the Planck scale. In the SM, the Higgs boson mass can be decomposed into a “bare” mass and a modification due to quantum corrections. Without SUSY, but in the presence of a high-energy new physics scale, these two numbers are extremely large and thus must almost exactly oppose one another – a peculiar coincidence called the hierarchy problem. SUSY introduces a set of new particles that each balances the mass correction of its SM partner, providing a “natural” explanation for the Higgs boson mass.

    Thanks to searches at the LHC and previous colliders, we know that SUSY particles must be heavier than their SM counterparts. But if this difference in mass becomes too large, particularly for the particles that produce the largest corrections to the Higgs boson mass, SUSY would not provide a natural solution of the hierarchy problem.

    New SUSY searches from ATLAS using data recorded at an energy of 13 TeV in 2015 and 2016 (some of which were shown for the first time at SUSY 2017 in Mumbai from 11–15 December) have extended existing bounds on the masses of the top squark and higgsinos, the SUSY partners of the top quark and Higgs bosons, respectively, that are critical for natural SUSY. For SUSY to remain natural, the mass of the top squark should be below around 1 TeV and that of the higgsinos below a few hundred GeV.

    ATLAS has now completed a set of searches for the top squark that push the mass limits up to 1 TeV. With no sign of SUSY yet, these searches have begun to focus on more difficult to detect scenarios in which SUSY could hide amongst the SM background. Sophisticated techniques including machine learning are employed to ensure no signal is missed.

    First ATLAS results have also been released for higgsino searches. If the lightest SUSY particles are higgsino-like, their masses will often be close together and such “compressed” scenarios lead to the production of low-momentum particles. One new search at ATLAS targets scenarios with leptons reconstructed at the lowest momenta still detectable. If the SUSY mass spectrum is extremely compressed, the lightest charged SUSY particle will have an extended lifetime, decay invisibly, and leave an unusual detector signature known as a “disappearing track”.

    Such a scenario is targeted by another new ATLAS analysis. These searches extend for the first time the limits on the lightest higgsino set by the Large Electron Positron (LEP) collider 15 years ago. The search for higgsinos remains among the most challenging and important for natural SUSY. With more data and new ideas, it may well be possible to discover, or exclude, natural SUSY in the coming years.

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  • richardmitnick 6:01 pm on February 13, 2018 Permalink | Reply
    Tags: , , , , , Particle Accelerators, , , Searches for dark photons at LHCb   

    From CERN Courier: “Searches for dark photons at LHCb” 


    CERN Courier

    1
    Comparing results

    CERN/LHCb detector

    The possibility that dark-matter particles may interact via an unknown force, felt only feebly by Standard Model (SM) particles, has motivated an effort to search for so-called dark forces.

    The force-carrying particle for such hypothesised interactions is referred to as a dark photon, A’, in analogy with the ordinary photon that mediates the electromagnetic interaction. While the dark photon does not couple directly to SM particles, quantum-mechanical mixing between the photon and dark-photon fields can generate a small interaction. This provides a portal through which dark photons may be produced and through which they might decay into visible final states.

    The minimal A’ model has two unknown parameters: the dark photon mass, m(A’), and the strength of its quantum-mechanical mixing with the photon field. Constraints have been placed on visible A’ decays by previous beam-dump, fixed-target, collider, and rare-meson-decay experiments.

    However, much of the A’ parameter space that is of greatest interest (based on quantum field theory arguments) is currently unexplored. Using data collected in 2016, LHCb recently performed a search for the decay A’→μ+μ– in a mass range from the dimuon threshold up to 70 GeV. While no evidence for a signal was found, strong limits were placed on the A’–photon mixing strength. These constraints are the most stringent to date for the mass range 10.6 < m(A') < 70 GeV and are comparable to the best existing limits on this parameter.

    Furthermore, the search was the first to achieve sensitivity to long-lived dark photons using a displaced-vertex signature, providing the first constraints in an otherwise unexplored region of A' parameter space. These results demonstrate the unique sensitivity of the LHCb experiment to dark photons, even using a data sample collected with a trigger that is inefficient for low-mass A' decays. Looking forward to Run 3, the number of expected A'→μ+μ− decays in the low-mass region should increase by a factor of 100 to 1000 compared to the 2016 data sample. LHCb is now developing searches for A'→e+e− decays which are sensitive to lower-mass dark photons, both in LHC Run 2 and in particular Run 3 when the luminosity will be higher. This will further expand LHCb’s dark-photon programme.

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  • richardmitnick 5:24 pm on February 13, 2018 Permalink | Reply
    Tags: , , , International committee backs 250 GeV ILC, Particle Accelerators,   

    From CERN Courier: “International committee backs 250 GeV ILC” 


    CERN Courier

    Jan 15, 2018

    1
    Plans scaled back.

    On 7 November, during its triennial seminar in Ottawa, Canada, the International Committee for Future Accelerators (ICFA) issued a statement of support for the International Linear Collider (ILC) as a Higgs-boson factory operating at a centre-of-mass energy of 250 GeV. That is half the energy set out five years ago in the ILC’s technical design report (TDR), shortening the length of the previous design (31 km) by around a third and slashing its cost by up to 40%.

    The statement follows physics studies by the Japanese Association of High Energy Physicists (JAHEP) and Linear Collider Collaboration (LCC) outlining the physics case for a 250 GeV Higgs factory. Following the 2012 discovery of the Higgs boson, the first elementary scalar particle, it is imperative that physicists undertake precision studies of its properties and couplings to further scrutinise the Standard Model. The ILC would produce copious quantities of Higgs bosons in association with Z bosons in a clean electron–positron collision environment, making it complementary to the LHC and its high-luminosity upgrade.

    ILC schematic, being planned for the Kitakami highland, in the Iwate prefecture of northern Japan

    One loss to the ILC physics program would be top-quark physics, which requires a centre-of-mass energy of around 350 GeV. However, ICFA underscored the extendibility of the ILC to higher energies via improving the acceleration technology and/or extending the tunnel length – a unique advantage of linear colliders – and noted the large discovery potential accessible beyond 250 GeV. The committee also reinforced the ILC as an international project led by a Japanese initiative.

    Thanks to experience gained from advanced X-ray sources, in particular the European XFEL in Hamburg (CERN Courier July/August 2017 p25), the superconducting radiofrequency (SRF) acceleration technology of the ILC is now well established.

    DESY European XFEL


    XFEL Gun

    Achieving a 40% cost reduction relative to the TDR price tag of $7.8 billion also requires new “nitrogen-infusion” SRF technology recently discovered at Fermilab.

    “We have demonstrated that with nitrogen doping a factor-three improvement in the cavity quality-factor is realisable in large scale machines such as LCLS-II, which can bring substantial cost reduction for the ILC and all future SRF machines,” explains Fermilab’s Anna Grassellino, who is leading the SRF R&D.

    SLAC LCLS-II

    “With nitrogen doping at low temperature, we are now paving the way for simultaneous improvement of efficiency and accelerating gradients of SRF cavities. Fermilab, KEK, Cornell, JLAB and DESY are all working towards higher gradients with higher quality factors that can be realised within the ILC timeline.”

    With the ILC having been on the table for more than two decades, the linear-collider community is keen that the machine’s future is decided soon. Results from LHC Run 2 are a key factor in shaping the physics case for the next collider, and important discussions about the post-LHC accelerator landscape will also take place during the update of the European Strategy for Particle Physics in the next two years.

    “The Linear Collider Board strongly supports the JAHEP proposal to construct a 250GeV ILC in Japan and encourages the Japanese government to give the proposal serious consideration for a timely decision,” says LCC director Lyn Evans.

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  • richardmitnick 3:42 pm on February 12, 2018 Permalink | Reply
    Tags: , Aleksandra Dimitrievska, , , , , , Particle Accelerators, ,   

    From LBNL- “From Belgrade to Berkeley: A Postdoctoral Researcher’s Path in Particle Physics” 

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    Berkeley Lab

    February 12, 2018

    Berkeley Lab’s Aleksandra Dimitrievska is working on a next-gen particle detector for CERN’s Large Hadron Collider

    1
    Aleksandra Dimitrievska works on prototype chips for a planned upgrade at CERN’s Large Hadron Collider. (Credit: Marilyn Chung/Berkeley Lab)

    After completing her Ph.D. thesis in calculating the mass of the W boson – an elementary particle that mediates one of the universe’s fundamental forces – physics researcher Aleksandra Dimitrievska is now testing out components for a scheduled upgrade of the world’s largest particle detectors.

    Dimitrievska left the University of Belgrade in Serbia late last year to join the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) as the recipient of an Owen Chamberlain Postdoctoral Fellowship in Experimental Particle Physics & Cosmology in the Lab’s Physics Division. The fellowship will extend up to five years.

    “Before, I was working behind a computer on coding. Now, I am in a clean room making wire bonds on computer chips, so it’s a much different experience,” Dimitrievska said. “I completely feel like a physicist now.”

    The Chamberlain Fellowship was created in 2002 to honor the late Owen Chamberlain, a Berkeley Lab physicist and UC Berkeley professor who received the Nobel Prize in Physics in 1959 for his work on the team that discovered the anti-proton using the Lab’s Bevatron accelerator. He also worked on the development of the time projection chamber, a type of detector that has been widely used in particle physics experiments.

    Dimitrievska’s path toward a career in particle physics led her to CERN’s Large Hadron Collider (LHC), a particle collider with an underground tunnel measuring 17 miles in circumference that is used to accelerate protons up to nearly the speed of light and collide them in detectors to measure the ensuing subatomic fireworks.

    “I started as a summer student at CERN in 2012. After that I went back to Belgrade – my Ph.D. advisor was involved in work on the W boson mass measurement,” she said. He connected her with a CERN team led by French physicist Maarten Boonekamp.

    The W boson and Z boson, which were both discovered in CERN experiments in 1983, are carriers of the “weak force” that is responsible for the particle process triggering fusion in the sun and other stars, the presence of radiation across the universe, and the breakdown of radioactive elements via a process known as beta decay. The W boson can have a positive or negative charge while the Z boson has a neutral charge, and each of these particles has a mass that is heavier than an iron atom.

    But despite such large masses, it has been difficult to pinpoint the W boson’s mass because of the typical noisy mess of other particle processes associated with its creation in collider experiments.

    “This is a really difficult measurement,” Dimitrievska said. The W boson’s mass must be calculated based on indirect measurements – a careful dissection of the data from related particle processes including recoil, in which particles are ejected from other particles in high-energy collisions at the LHC.

    “We started from scratch, one step at a time,” she said, to find the best way to calibrate the W boson measurements. “We tried different approaches and different ideas. The most important things are the uncertainties,” she said, and in finding ways to reduce the uncertainties in the analyses of data from experiments. “It takes a lot of time to really calibrate each source.”

    The team conducting the analysis found that a useful way to measure the W boson is to use measurements of the Z boson for calibration. “You are calibrating the recoil on the Z boson events, and then you extrapolate (measurements) for the W boson,” she said, based in part on the uncertainties in the Z boson measurements.

    The team worked with data from millions of particle collisions that produced candidate W bosons in the 2011 run of the LHC. Ongoing studies will apply the same techniques developed for the 2011 analysis for larger sets of data accumulated at the LHC in 2012, 2015, and 2016. The latest sets of LHC data, because they can involve larger numbers of colliding protons, are even more challenging to pick through in isolating individual particle properties.

    Such painstaking analyses can ultimately test whether the standard model of particle physics, developed through decades of experiments and theories, holds up to increasingly precise measurements.

    In this case, Dimitrievska’s team found good agreement in their measurements with the standard model. “There is no hint of physics beyond the standard model, but this result is important because we have something new to put in front of the theoretical ideas and see where there is place for improvement in the measurements,” she said.

    She added, “The calibration and methods we used will also be used for other measurements at higher energies.”

    The latest measurement, published Feb. 6 in the European Physical Journal C, determined the mass of the W boson to be about 80,370 mega (million) electronvolts, or MeV, with a statistical uncertainty of plus or minus 7 MeV, which is consistent with an average from previous measurements of about 80,385 MeV, with uncertainty at plus or minus 15 MeV. An electronvolt is a unit of energy that is a common measure of mass for subatomic particles.

    Dimitrievska successfully defended her Ph.D. thesis on the W boson mass measurement at the University of Belgrade in December.

    Her current work at Berkeley Lab is focused on testing 2-centimeter-by-1-centimeter prototype computer chips for the planned High-Luminosity LHC at CERN that will produce a higher volume of particle collisions and data.

    “Because we will have more data, the readout system has to be faster,” she said. “Basically, we have to improve everything.”

    2
    Aleksandra Dimitrievska holds a prototype chip for planned detector upgrades at CERN. (Credit: Marilyn Chung/Berkeley Lab)

    The final version of the chips that she is testing will be installed in the inner part of the ATLAS and CMS detectors at CERN and must be radiation-hardened to withstand the constant drumming of high-energy particles. She has used 3-D printers at UC Berkeley to fabricate prototype components related to the chip assemblies she works with.

    “For now, I am just testing if the chips work – how they are collecting data,” she said. A next step for her research group is to set up a particle beam to monitor how the chips perform under simulated experimental conditions.

    As an active member of Berkeley Lab’s ATLAS collaboration team, Dimitrievska also participates remotely in several meetings per week hosted at CERN, and she said she looks forward to the opportunity to work on the LHC upgrade project as it moves forward from its R&D stages to actual fabrication, assembly, and installation.

    “I think this is the really nice part about this work,” she said. “You can see the development of something that you can actually use later. You can participate first in the development of the detector, and then do the analysis and see how it really works.”

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  • richardmitnick 9:54 am on February 12, 2018 Permalink | Reply
    Tags: , , , First high-precision measurement of the mass of the W boson at the LHC, , , Particle Accelerators, ,   

    From CERN ATLAS : “First high-precision measurement of the mass of the W boson at the LHC” 

    CERN ATLAS Higgs Event

    CERN/ATLAS
    ATLAS

    12th February 2018

    1
    Display of a candidate event for a W boson decaying into one muon and one neutrino from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 7 TeV. (Image: ATLAS Collaboration/CERN).

    In a paper published today in the European Physical Journal C, the ATLAS Collaboration reports the first high-precision measurement at the Large Hadron Collider (LHC) of the mass of the W boson. This is one of two elementary particles that mediate the weak interaction – one of the forces that govern the behaviour of matter in our universe. The reported result gives a value of 80370±19 MeV for the W mass, which is consistent with the expectation from the Standard Model of Particle Physics, the theory that describes known particles and their interactions.

    The measurement is based on around 14 million W bosons recorded in a single year (2011), when the LHC was running at the energy of 7 TeV. It matches previous measurements obtained at Large Electron-Positron Collider[LEP] , the ancestor of the LHC at CERN, and at the Tevatron , a former accelerator at Fermilab [FNAL] in the United States, whose data made it possible to continuously refine this measurement over the last 20 years.

    2
    CERN LEP

    3
    FNAL Tevatron

    FNAL/Tevatron

    The W boson is one of the heaviest known particles in the universe. Its discovery in 1983 crowned the success of CERN’s Super Proton Synchrotron , leading to the Nobel Prize in physics in 1984. Although the properties of the W boson have been studied for more than 30 years, measuring its mass to high precision remains a major challenge.

    4
    Super Proton Synchrotron

    “Achieving such a precise measurement despite the demanding conditions present in a hadron collider such as the LHC is a great challenge,” said the physics coordinator of the ATLAS Collaboration, Tancredi Carli. “Reaching similar precision, as previously obtained at other colliders, with only one year of Run 1 data is remarkable. It is an extremely promising indication of our ability to improve our knowledge of the Standard Model and look for signs of new physics through highly accurate measurements.”

    The Standard Model is very powerful in predicting the behaviour and certain characteristics of the elementary particles and makes it possible to deduce certain parameters from other well-known quantities. The masses of the W boson, the top quark and the Higgs boson for example, are linked by quantum physics relations. It is therefore very important to improve the precision of the W boson mass measurements to better understand the Higgs boson, refine the Standard Model and test its overall consistency.

    Remarkably, the mass of the W boson can be predicted today with a precision exceeding that of direct measurements. This is why it is a key ingredient in the search for new physics, as any deviation of the measured mass from the prediction could reveal new phenomena conflicting with the Standard Model.

    The measurement relies on a thorough calibration of the detector and of the theoretical modelling of the W boson production. These were achieved through the study of Z boson events and several other ancillary measurements. The complexity of the analysis meant it took almost five years for the ATLAS team to achieve this new result. Further analysis with the huge sample of now-available LHC data, will allow even greater accuracy in the near future.

    See the full article here .

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  • richardmitnick 3:19 pm on February 9, 2018 Permalink | Reply
    Tags: , , , Elastic scattering, , Particle Accelerators, ,   

    From CERN: “Odd gluon compounds may be lurking in the protons” 

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    9 Feb 2018.
    Iva Raynova


    CERN TOTEM

    Protons are known to contain quarks and gluons. But are gluons behaving as expected?

    Scientists from the TOTEM (Total, elastic and diffractive cross-section measurement) collaboration may have found indirect evidence of a subatomic gluon-compound in proton-proton collisions. First theorised in the 1970s, such a state, then dubbed “Odderon”, consists of an odd number of gluons.

    Usually, the protons that collide in the LHC shatter and create new particles. Sometimes though, in about 25 percent of the time, they survive the encounter intact. Instead of breaking in pieces, they only change their direction and emerge from the detector at very small angles to the beampipe – their deviation at a 200-metre distance is in the order of one millimetre. This kind of interaction is called “elastic scattering” and it is the specialty of TOTEM, CERN’s longest experiment. To be able to detect the survived protons, its detectors are spread across almost half a kilometre around the CMS interaction point.

    The quarks in the proton are bound by gluons, the carriers of the strong force. Physicists have successfully explained elastic scattering at low-momentum transfer and high energies with the exchange of a “Pomeron”, which in modern language is a state of two teamed-up gluons.

    TOTEM precisely measured the elastic-scattering process at 13 TeV to extract the total probability for proton-proton collisions as well as the so-called rho parameter that helps to explain the difference in proton-proton and antiproton-proton scattering.

    Combining these two measurements, TOTEM finds better agreement with theoretical models that indicate the exchange of three aggregated gluons. Although this exchange has been predicted by the Quantum Chromodynamics (QCD) theory back in the 1980s, no experimental evidence had been presented to date.

    The measurements also hint towards a slow-down of the total probability of scattering with energy. While somewhat expected at the very highest energy, there has been no indication of such an effect in previous data.

    “These measurements explore for the first time the behaviour of protons in elastic interactions at the highest energy of 13 TeV. These results obtained with a record precision were made possible by the excellent performance of the TOTEM detectors and the exceptional capabilities of the Large Hadron Collider,” observed Simone Giani, the TOTEM spokesperson.

    If three gluons really were to form a compound, it should appear in other scattering experiments. Physicists are hence looking forward to dedicated experiments to establish whether such a compound is actually being formed. In order to further explore and confirm the theoretical interpretations, a special LHC proton run at an energy of 900 GeV is planned to take place in 2018 to collect more data and it will involve also other LHC experiments.

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  • richardmitnick 11:52 am on February 7, 2018 Permalink | Reply
    Tags: , , , , Evangelia Gousiou, , , Jeny Teheran, Particle Accelerators, , , Sima Baymani,   

    From CERN and FNAL: Women in STEM- “Coding has no gender” Sima Baymani, Jeny Teheran, Evangelia Gousiou 

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    FNAL Art Image by Angela Gonzales

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

    5 Feb 2018
    Kate Kahle
    Lauren Biron

    1
    Sima Baymani: “You can work all over the world, because programming is the same everywhere. The choices you have are endless.”

    With 11 February marking the International Day of Women and Girls in Science, female physicists, engineers and computer scientists from CERN and from Fermilab share their experiences of building a career in science.

    Sima Baymani: “There is a lot of collaboration, and this, for me, is part of the joy of programming”


    Computer science engineer, Sima Baymani, talks about the freedom, creativity and collaboration of computer programming. (Video: Jacques Fichet/CERN)

    Computer science engineer, Sima Baymani was born in Iran before her family fled war when she was young to start a new life in Sweden. Her parents were academics, and Sima and her sisters were always encouraged to learn more about everything. Her mother, a physicist, had to restart her career in Sweden and chose to pursue database management and programming. Her enjoyment of her job, coupled with an inspiring Danish mathematics teacher, were two factors that helped lead Sima towards studying computer science.

    “In school I was interested in almost all subjects. But I can see that the IT boom in Sweden had an effect on me, and on other women, because when we started university it was one of the peaks of women studying computer science.” At university, Sima wanted to understand how computers worked, so she specialised in hardware and embedded systems. After graduation she worked as an independent consultant for 10 years before joining CERN.

    She has encountered challenges in fighting gender and ethnic stereotypes, and often felt that she had to work harder to prove herself. Yet part of her joy of programming is collaborating with colleagues to find creative solutions to complex problems and to develop new products or new functionality. “Technology is everywhere in our society; the problems and solutions you can work with creatively are endless,” she enthuses.

    Jeny Teheran: “What I love the most is to work with teams around the world.”


    Jeny Teheran shares the best parts of being a security analyst and cybersecurity researcher at Fermilab. (Video: Fermilab)

    Jeny Teheran is a security analyst and cybersecurity researcher at Fermi National Accelerator Laboratory. That means keeping up with and taking care of hardware and software vulnerabilities so that the experiments can carry out their science in a secure manner. It’s a fast-paced job where you have to come up with the best solution you can put in place, right in the moment.

    “I would recommend this job because it challenges you. It pushes you to be on top of your game. You have to improve your analytical skills; you have to react fast; you have to communicate better.” – Jeny Teheran

    Jeny came to Fermilab from the Caribbean coast of Colombia. She grew up in a house with few toys but lots of books, and says she has always felt close to science. With a degree in systems and computing engineering, she arrived at Fermilab four years ago as an intern to work in the offline production team for neutrino experiments. A year later, she was hired as a security analyst. “And I’m loving it,” she says.

    Evangelia Gousiou: “Nothing beats the rush you get when something that you designed works for the first time.”


    Electronics engineer, Evangelia Gousiou, talks about what led her to a career in engineering. (Video: Jacques Fichet/CERN)

    Electronics engineer, Evangelia Gousiou, began her career studying IT and Electronics in Athens, Greece, before beginning an internship at a manufacturing plant in Thailand. She came to CERN for a one-year position, and now, ten years later is still at CERN enjoying a job that is never boring.

    “Work is never repetitive, which makes it very rewarding. I usually follow a project through all its stages from conception of the architecture, to the coding and the delivery to the users of a product that I have built to be useful for them. So I see the full picture and that keeps me engaged.” – Evangelia Gousiou

    For Evangelia, to be a good electronics engineer means knowing a range of disciplines, from software to mechanics. There is also the human aspect, as she works daily with people from many different cultures.

    At school, her favourite subjects were maths and physics, as she enjoyed finding out how things worked, yet Evangelia never dreamt of being an engineer when she grew up. When the time came to choose what to study, she felt that engineering would be something interesting and future-proof, and then she got hooked and now can’t imagine doing anything else. “I would recommend engineering professions for their intellectual challenge and the empowerment that they bring,” she beams.

    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:

    Quantum Diaries
    QuantumDiaries

    Cern Courier

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New

    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
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    LHC

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    CERN LHC particles

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  • richardmitnick 4:37 pm on February 6, 2018 Permalink | Reply
    Tags: , Fermilab’s Muon g-2 experiment officially starts up, , , , Particle Accelerators, ,   

    From FNAL: “Fermilab’s Muon g-2 experiment officially starts up” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    February 6, 2018
    Bruno Martin

    FNAL Muon g-2 studio


    Fermilab’s Muon g-2 experiment has officially begun taking data. Pictured here is the centerpiece of the experiment, a 50-foot-wide electromagnet ring, which generates a uniform magnetic field so scientists can make measurements of particles called muons with immense precision. Photo: Reidar Hahn

    The Muon g-2 experiment at Fermilab, which has been six years in the making, is officially up and running after reaching its final construction milestone. The U.S. Department of Energy on Jan. 16 granted the last of five approval stages to the project, Critical Decision 4 (CD-4), formally allowing its transition into operations.

    “We laid down the plans for Muon g-2 early on and have stuck to that through four years of construction,” said Fermilab’s Chris Polly, the experiment’s co-spokesperson and former project manager. “We’ve come out on schedule and under budget, which sets a good precedent for all the other projects.”

    The experiment will send particles called muons — heavier cousins of the electron — around a 50-foot-wide muon storage ring that was relocated from Brookhaven National Laboratory in New York state in 2013. The uniform magnetic field inside the ring exerts a torque that affects the muons’ own spins, causing them to wobble. In the early 2000s, scientists at Brookhaven found the value of this wobble, called magnetic precession, to be different from the “g-2” value predicted by theory.

    At Fermilab, the Muon g-2 experiment aims to confirm or refute this intriguing discrepancy with theory by repeating the measurements with a fourfold improvement in accuracy, up to 140 parts per billion. That’s like measuring the length of a football field with a margin of error that is only one-tenth the thickness of a human hair. If the experimental deviation from theory turns out to be real, it would mean that undiscovered forces or particles beyond the Standard Model — the theoretical framework that describes how the universe works — are appearing and disappearing from the vacuum to disturb the muons’ magnetic moment.

    And if it isn’t?

    “Well, if we find the measurement is consistent with theory, it will allow us to narrow our search for new physics, since it will rule out some current models that would no longer be viable,” Polly said.

    For example, Polly added, there are theories positing the existence of supersymmetric particles — superheavy partners to those in the Standard Model — and new categories of particles that could be the constituents of the mysterious dark matter, which makes up 80 percent of the universe’s mass. Some of these theories would no longer be valid.

    “That’s the value of a null result,” Polly said. “It helps us make sure that the theories that we would use to try to understand these other bigger questions are consistent.”

    All that’s left now is to finish fine-tuning the instruments so the experiment can start its several-year run of data collection.

    “For most of the team, this was the first project we’ve worked on,” said Fermilab physicist Mary Convery, who served as the experiment’s deputy project manager. “To see it through from design to construction and now to operations has been very rewarding.”

    Muon g-2 operations got a head start in June 2017, when the team fired up the particle beam to start calibrating the detectors and tweaking components that required additional work.

    “Since the accelerator turned back on in November, we have been commissioning the beamlines, the storage ring and the rest of the experiment,” said University of Washington physicist David Hertzog, Muon g-2 co-spokesperson.

    As early as next month, Muon g-2 will be ready to start collecting physics-quality data at Fermilab and explore the nature of the previously measured g-2 discrepancy.

    “We’ve set ourselves the goal of collecting three times the amount of data that they had in Brookhaven’s three-year run during this first spring season,” Hertzog said. “But this is just the very beginning: The experiment will run with higher intensity next year. The ultimate goal is to collect 21 times the Brookhaven statistics.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    FNAL Icon

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

     
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