2,824 research outputs found
Crystal collimation studies at the Tevatron (T-980)
No full textBent-crystal channeling is a technique with a potential to increase beam-halo collimation efficiency in high-energy colliders. First measurements at the Tevatron in 2005 have shown that using a thin silicon crystal to deflect the 1-TeV proton beam halo onto a secondary collimator improves the system performance by reducing the machine impedance, beam losses in the collider detectors and irradiation of the superconducting magnets, all in agreement with simulations. Recent results, obtained with an improved goniometer and enhanced beam diagnostics, are reported here for dedicated beam studies and first full collider stores along with simulation results and plans for substantial enhancement of the T-980 experimental setup
Electroweak physics and evidence for a Higgs boson decaying to a pair of tau leptons with the CMS detector
No full textThesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 157-170)..Studies of the electroweak interactions using final states with leptons in proton-proton collisions at the Large Hadron Collider at [square root of] s = 7 TeV, [square root of] s = 8 TeV, and [square root of] s = 13 TeV center-of-mass energies are described. Measurements of total inclusive and fiducial W and Z boson production cross sections and their ratios are performed. The W and Z bosons are observed via their decays to electrons and muons. An indirect determination of the total width of the W boson and the B(W --> lv) from the measured cross section ratios is described. The discovery of a new boson with a mass of 125 GeV at the Large Hadron Collider in 2012 sheds a new light on understanding the nature of electroweak symmetry breaking. A question of great significance is whether the new field couples to fermions through a Yukawa coupling interaction predicted in the standard model of particles. Evidence of the 125 GeV Higgs boson decay to a pair of tau leptons with an observed significance of 3.1 standard deviations is established. The nature of the Higgs sector is probed through searches for neutral resonances decaying to a pair of tau leptons in gluon-fusion and b-quark associated production modes with no observation of a significant excess. In addition, the feasibility of measuring the standard model Higgs boson self-coupling with an expected data sample corresponding to an integrated luminosity of 3000 fb-1 is studied.by Aram Apyan.Ph. D
Crystal Collimation Studies at the Tevatron (T-980)
No full textBent-crystal channeling is a technique with a potential to increase the beam-halo collimation efficiency at high-energy colliders. First measurements at the Tevatron in 2005 have shown that using a 5-mm silicon crystal to deflect the proton beam halo onto a secondary collimator improves the system performance by reducing the machine impedance, beam losses in the collider detectors and irradiation of the superconducting magnets, all in agreement with simulations. Recent results, obtained with substantially improved goniometer and enhanced beam diagnostics, are reported showing channeling collimation of the ~1-TeV circulating proton beam halo at the Tevatron collider. Comprehensive results of computer modeling are presented which allow further developments of the T-980 experiment towards a robust system compatible with requirements to high-efficient collimation at the Tevatron and LHC hadron colliders
Electroweak Precision Measurements with Z Bosons at the LHC
No full textMeasurements of the forward-backward asymmetry in the neutral current annihilation process , where denotes a muon or electron, at the LHC are reported. The forward-backward asymmetry is measured as a function of the dilepton invariant mass yielding the effective weak mixing angle. The effective weak mixing angle values of and are obtained by the ATLAS and LHCb collaborations, respectively. The results are in agreement with the current world average
CLIC Post-Collision Line Luminosity Monitoring
No full textThe CLIC post collision line is designed to transport the un-collided beams and the products of the collided beams with a total power of 14MW to the main beam dump. Full Monte Carlo simulation has been done for the description of the CLIC luminosity monitoring in the post collision line. One method of the luminosity diagnostic is based on the detection of high energy muons produced by beamstrahlung photons in the main beam dump. The disrupted beam and the beamstrahlung photons produce at the order of 106 muons per bunch crossing per cm2, with energies higher than 10 GeV. Threshold Cherenkov counters are considered after the beam dump for the detection of these high energy muons. Another method for luminosity monitoring is presented using the direct detection of the beamstrahlung photons
Measurement of the top quark mass with lepton+jets final states using pp collisions at root s = 13TeV (vol 78, 891, 2018)
No full textIn this article the author name Luigi Calligaris was incorrectly written as A. Calligaris. The original article has been corrected
Search for new physics in dijet angular distributions using proton-proton collisions at root s = 13TeV and constraints on dark matter and other models (vol 78, 789, 2018)
No full textIn this article the author name Luigi Calligaris was incorrectly written as A. Calligaris. The original article has been corrected
Measurement of exclusive Upsilon photoproduction from protons in pPb collisions at root s(NN) = 5.02 TeV (vol 79, 277, 2019)
No full textIn this article the author name Luigi Calligaris was incorrectly written as A. Calligaris. The original article has been corrected
Extraction Line and Beam Dump for the Future Electron Positron Circular Collider
No full textThe conceptual design of an extraction line and beam dump for the future electron positron circular collider is presented. The proposed extraction line, consisting of abort kicker system, spoilers and beam diagnostics apparatus transports the electron and positron beams to the main beam dumps. The beam must be spread over a large surface in order not to damage the beam dump and the window, which separates the ring from the dump. The extraction line redistributes bunches at different locations on the face of beam dump. Monte Carlo simulations using FLUKA have been performed to estimate the distribution of energy deposition on the window and beam dump to find the optimal absorber and its dimensions
Flight Operations
No full textOutline the process that takes new hires with zero knowledge all the way to the point of completing missions in Flight Operations. Audience members should be able to outline the attributes of a flight controller and instructor, outline the training flow for flight controllers and instructors, and identify how the flight controller and instructor attributes are necessary to ensure operational excellence in mission prep and execution. Identify how the simulation environment is used to develop crisis management, communication, teamwork, and leadership skills for SGT employees beyond what can be provided by classroom training
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