2,380 research outputs found

    Search for ADD Extra Dimensional Gravity in Dimuon Channel with the CMS Detector

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    In this work a possibility to observe TeV-scale gravity signals at the LHC is discussed. The ADD scenario with large extra dimensions and KK-modes virtual contribution into Drell-Yan processes are considered. A full simulation and reconstruction analysis was carried out to derive the CMS discovery potential for ADD virtual production by studying muon pairs with large invariant masses

    Study of Drell-Yan Di-muon Production with the CMS Detector

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    The potential of the Compact Muon Solenoid (CMS) experiment to measure Drell-Yan muon pairs is studied. The efficiency of Level-1 and High Level Triggers to these events is investigated. Muon pairs can be explored by CMS with high precision up to very high invariant masses. Systematic errors are considered. The possibility of performing precise measurements of the forward-backward asymmetry is discussed

    Search for Randall-Sundrum Graviton Decay into Muon Pairs

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    In this work the study of Randall-Sundrum graviton decay into muon pairs has been performed. A full simulation and reconstruction analysis was carried out to derive both the CMS discovery potential for Randall-Sundrum graviton and spin determination performance in this channel

    Electrode Strip Deposition for the CMS Barrel Drift Tube System

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    The full production ideation, design, set up and realization of the Electrode Strip Deposition for the entire construction of the CMS Barrel Drift Tube System are described in detail

    Dark sectors 2016 Workshop: community report

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    This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years

    Design, Performance, and Calibration of CMS Hadron-Barrel Calorimeter Wedges

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    Extensive measurements have been made with pions, electrons and muons on four production wedges of the Compact Muon Solenoid (CMS) hadron barrel (HB) calorimeter in the H2 beam line at CERN with particle momenta varying from 20 to 300 GeV/c. Data were taken both with and without a prototype electromagnetic lead tungstate crystal calorimeter (EB) in front of the hadron calorimeter. The time structure of the events was measured with the full chain of preproduction front-end electronics running at 34 MHz. Moving-wire radioactive source data were also collected for all scintillator layers in the HB. These measurements set the absolute calibration of the HB prior to first pp collisions to approximately 4%

    Energy Response and Longitudinal Shower Profiles Measured in CMS HCAL and Comparison With Geant4

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    The response of the CMS combined electromagnetic and hadron calorimeter to beams of pions with momenta in the range 5-300 GeV/c has been measured in the H2 test beam at CERN. The raw response with the electromagnetic compartment calibrated to electrons and the hadron compartment calibrated to 300 GeV pions may be represented by sigma = (1.2) sqrt{E} oplus (0.095) E. The fraction of energy visible in the calorimeter ranges from 0.72 at 5 GeV to 0.95 at 300 GeV, indicating a substantial nonlinearity. The intrinsic electron to hadron ratios are fit as a function of energy and found to be in the range 1.3-2.7 for the electromagnetic compartment and 1.4-1.8 for the hadronic compartment. The fits are used to correct the non-linearity of the e pi response to 5% over the entire measured range resulting in a substantially improved resolution at low energy. Longitudinal shower profile have been measured in detail and compared to Geant4 models, LHEP-3.7 and QGSP-2.8. At energies below 30 GeV, the data, LHEP and QGSP are in agreement. Above 30 GeV, LHEP gives a more accurate simulation of the longitudinal shower profile

    Synchronization and Timing in CMS HCAL

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    The synchronization and timing of the hadron calorimeter (HCAL) for the Compact Muon Solenoid has been extensively studied with test beams at CERN during the period 2003-4, including runs with 40 MHz structured beam. The relative phases of the signals from different calorimeter segments are timed to 1 ns accuracy using a laser and equalized using programmable delay settings in the front-end electronics. The beam was used to verify the timing and to map out the entire range of pulse shapes over the 25 ns interval between beam crossings. These data were used to make detailed measurements of energy-dependent time slewing effects and to tune the electronics for optimal performance

    Efficiency of Finding Muon Track Trigger Primitives in CMS Cathode Strip Chambers

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    In the CMS Experiment, muon detection in the forward direction is accomplished by cathode strip chambers~(CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using~36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge~(MTCC) exercise conducted by the~CMS experiment in~2006. In contrast to earlier studies that used muon beams to illuminate a very small chamber area (< ⁣0.01< \! 0.01~m2^2), results presented in this paper were obtained by many installed CSCs operating {\em in situ} over an area of  ⁣23\approx \! 23~m2^2 as a part of the~CMS experiment. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be~99.93±0.03%99.93 \pm 0.03\%. These segments, found by the CSC electronics within 800800~ns after the passing of a muon through the chambers, are the input information for the Level-1 muon trigger and, also, are a necessary condition for chambers to be read out by the Data Acquisition System

    Design, Performance, and Calibration of the CMS Hadron-Outer Calorimeter

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    The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with an outer calorimeter to ensure high energy shower containment in the calorimeter. Fabrication, testing and calibration of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing \et measurements at LHC energies. The outer hadron calorimeter will also be used for the muon trigger in coincidence with other muon chambers in CMS
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