Muon Momentum Resolution Research Articles

Studies of the muon momentum calibration and performance of the ATLAS detector with pp collisions at sqrt{s}=13 TeV

This paper presents the muon momentum calibration and performance studies for the ATLAS detector based on the pp collisions data sample produced at sqrt{s} = 13 TeV at the LHC during Run 2 and corresponding to an integrated luminosity of 139 {textrm{fb}}^{-1}. An innovative approach is used to correct for potential charge-dependent momentum biases related to the knowledge of the detector geometry, using the Zrightarrow mu ^{+}mu ^{-} resonance. The muon momentum scale and resolution are measured using samples of J/psi rightarrow mu ^{+}mu ^{-} and Zrightarrow mu ^{+}mu ^{-} events. A calibration procedure is defined and applied to simulated data to match the performance measured in real data. The calibration is validated using an independent sample of Upsilon rightarrow mu ^{+}mu ^{-} events. At the Z(J/psi ) peak, the momentum scale is measured with an uncertainty at the 0.05% (0.1%) level, and the resolution is measured with an uncertainty at the 1.5% (2%) level. The charge-dependent bias is removed with a dedicated in situ correction for momenta up to 450 GeV with a precision better than 0.03 {textrm{TeV}}^{-1}.

Expected measurement precision with production at the CEPC * *Supported by the Innovative Research Program of IHEP (E2545AU210); CAS Center for Excellence in Particle Physics; Yifang Wang’s Science Studio of the Ten Thousand Talents Project; the CAS/SAFEA International Partnership Program for Creative Research Teams (H751S018S5); IHEP Innovation Grant (Y4545170Y2); Key Research Program of Frontier Sciences, CAS (XQYZDY-SSW-SLH002); Chinese Academy of

A search for the dimuon decay of the Standard Model Higgs boson is performed using Monte Carlo simulated events to mimic data corresponding to an integrated luminosity of 5.6 ab collected with the Circular Electron-Positron Collider detector in collisions at GeV. This study investigates the process, and the expected significance considering only the statistical uncertainty in the data for a background-only hypothesis for a Higgs boson with a mass of 125 GeV is found to be 6.1 , corresponding to a precision of 19%. The systematic impacts from the background Monte Carlo statistical fluctuations are estimated to be negligible. Moreover, the dependence of the measurement accuracy on the muon momentum resolution of the CEPC detector is investigated. It is found that the muon momentum resolution must be better than 204 MeV to discover the process at the nominal integrated luminosity. If the resolution is 100% worse than the designed parameter, the integrated luminosity must be greater than 7.2 ab to reach 5 significance.

Muon momentum scale and resolution in pp collisions at [formula omitted] in ATLAS

This work shows the performance in the muon momentum scale and resolution achieved by ATLAS during the 2012 run at s=8. The momentum scale is known with an uncertainty ranging from 0.05% (in the central rapidity region) to 0.2% (at large rapidities). The muon momentum resolution is measured to be 1.7% for central muons with low momentum (pT≃10 GeV) and reaches 4% for high-pT muons in the forward regions of the ATLAS detector.

Muon reconstruction and identification in CMS Run I and towards Run II

The performance of the muon reconstruction and identification in the CMS experiment at the LHC has been studied on data collected in pp collisions at s=7 and 8 TeV. Results from the measurements of the muon identification efficiencies, hadron misidentification probabilities as well as the muon momentum scale and resolution are presented.

Performance of the muon identification and reconstruction with the ATLAS detector

We present the muon reconstruction algorithms used in ATLAS during the LHC run-1 and their performances in terms of efficiency, muon momentum scale and resolution. These performances have been measured using large calibration samples of J /ψ , ϒ and Z decays, which allow to control the systematic uncertainties on efficiency and on momentum scale at the per-mille level. Corrections to be applied to simulation have been derived from the performances measurements and used in physics analyses. The impact of these correction on physics measurements, and the associated uncertainties, is also presented.

Muon reconstruction efficiency and momentum resolution of the ATLAS experiment in proton-proton collisions at [Formula: see text]TeV in 2010.

This paper presents a study of the performance of the muon reconstruction in the analysis of proton–proton collisions at sqrt{s}=7 TeV at the LHC, recorded by the ATLAS detector in 2010. This performance is described in terms of reconstruction and isolation efficiencies and momentum resolutions for different classes of reconstructed muons. The results are obtained from an analysis of J/psi meson and Z boson decays to dimuons, reconstructed from a data sample corresponding to an integrated luminosity of 40 pb^{-1}. The measured performance is compared to Monte Carlo predictions and deviations from the predicted performance are discussed.

Measurement of muon momentum resolution of the ATLAS detector

The ATLAS detector has been designed to have good muon momentum resolution up to momenta in the TeV range. The muon momentum resolution of the ATLAS spectrometer has been measured with p-p collision data recorded in 2011. The measurement combines the di-muon mass resolution in J/\Psi->\mu\mu and Z->\mu\mu decays with measurements of the alignment accuracy of the detector based on straight muon tracks, which are acquired with special runs without magnetic field in the ATLAS detector.

Commissioning of the muon track reconstruction in the ATLAS experiment

The Muon Spectrometer for the ATLAS experiment at the LHC is designed to identify muons with transverse momentum greater than 3 GeV/c and measure muon momenta with high precision up to the highest momenta expected at the LHC. The 50 μm sagitta resolution translates into a transverse momentum resolution of 10% for muons with transverse momenta of 1 TeV/c. The target muon momentum resolution requires an accurate knowledge of the positions and orientations of the muon chambers, as well as their internal deformations. The optical and track based alignment are shown to perform as expected. Accurate calibration of the time to distance relation in the Monitored Drift Tubes (MDTs) is also required to reach design performance. The software chain that implements corrections for the alignment and calibration of the chambers is described, as well as the algorithms implemented to perform muon identification and measurement in ATLAS. The performance of the complete software chain is covered in the context of first single-beam LHC running as well as ATLAS cosmics data taking. The software is robust and reconstructs local track segments with high (> 99%) efficiency.

Search for the neutral MSSM Higgs bosons in the bbH, H → μ+μ− topology with the ATLAS detector

Motivated by the high muon momentum resolution and identification efficiency achievable with the ATLAS detector, currently being installed at CERN, we explore the observability of the supersymmetric h/A/H decays to two muons. The high experimental resolution in this decay mode compensates to some extent for the suppression of the branching ratio, with respect to the h/A/H → τ τ decays. The search is performed in a wide Higgs mass range, starting from 110 GeV/c2. In the case of gg → bb(h/H/A) production mode, the additional b-jets produced in association with the h/H/A bosons are used to suppress the background.Using fully simulated signal and background event samples, we study the performance of the reconstruction algorithms relevant to the analysis, such as the muon reconstruction, b-tagging and the measurement of the missing energy. The influence of the detector misalignment on the reconstruction performance is also taken into consideration. Emphasis is given on the optimization of the event selection procedure and the corresponding selection criteria, taking into account the different background composition depending on the mass range in which the Higgs search is performed.

Precision aspects of ATLAS muon chamber design and construction

The ATLAS Muon Collaboration is aiming to build a Muon Spectrometer with unprecedented standalone muon momentum resolution of ∼10% at particle momenta of 1 TeV/c over a wide range of transverse momenta, pseudorapidity, and azimuthal angle. The ATLAS Muon Spectrometer consists mainly of Monitored Drift Tube (MDT) chambers for precision tracking, installed everywhere except in the very forward area where Cathode Strip Chambers will be used. The precision chambers are complemented by trigger chambers which are Resistive Plate Chambers for the Barrel region and with Thin Gap Chambers in the Endcap region of the spectrometer. In order to achieve the targeted excellent momentum resolution, wires within the MDT chambers have to be positioned with an accuracy of 20 μm (rms) to avoid limiting the overall chamber resolution of ∼50 μm. We will discuss aspects of a worldwide distributed precision production of the 1200 MDT chambers needed for the spectrometer, including construction and quality control aspects up until commissioning.

The first precision drift tube chambers for the ATLAS muon spectrometer

The muon spectrometer of the ATLAS detector for the Large Hadron Collider is designed to provide a muon transverse momentum resolution of 2%–10% for momenta between 6 GeV and 1 TeV over a pseudo-rapidity range of | η|⩽2.7. This required the development of precision drift chambers with a track position resolution of 40 μ m, the Monitored Drift Tube (MDT) chambers. We report about the construction of the three main types of MDT chambers for ATLAS, test results and the first production experience.

Performance of a magnetized calorimeter for a long baseline neutrino oscillation experiment

In this paper we present a study of the momentum measurement ability of the magnetized calorimeter proposed for the ICANOE experiment. For the calorimeter tracker we have designed a system based on aluminum drift tubes 8.5 m long and with a square inner cross-section of 2.6×2.6 cm 2 , fed by an Ar–CO 2 gas mixture. Magnetic field measurements performed on reduced scale prototypes show that an average magnetic flux density of ∼1.3 T can be achieved. From tests with cosmic rays and beam particles, we also show that the drift tubes used for the tracker allow to obtain spatial resolutions better than 400 μm . The muon momentum resolution achievable with the proposed layout is ∼30%.

High-precision spectroscopy with the ATLAS muon system

The ATLAS muon spectrometer will measure muon tracks along a spectrometer arm of up to 15 m length, embedded in a magnetic field of ∼0.5 T . The precision tracking devices in the muon system will be high-pressure drift tubes (MDTs). To achieve a momentum resolution of ∼10% for muons with a transverse momentum of p T =1 TeV/c , the systematic error to the space–time relationship has to be smaller than δ r.m.s. <70 μm . Contributions to a systematic error δ r.m.s. and its impact on the muon-momentum resolution are discussed. LHC physics require excellent knowledge of the absolute momentum scale. We show a calibration method which will achieve an accuracy at the 10 −4 level.

Design of the superconducting end cap toroids for the ATLAS experiment at LHC

The ATLAS experiment proposed for LHC will use a toroidal magnet system to achieve high efficiency muon momentum resolution. The end cap toroids are designed to provide bending powers in the range 4-8 Tm over the rapidity span 1.5-2.8 in the important forward/backward regions. Each end cap toroid will have an outer diameter of approximately 11 m and an axial length of 5.6 m. This paper presents the magnetic, mechanical and cryogenic design of the end cap toroid magnet systems. Particular emphasis is placed on the interactive design issues imposed by the close proximity of the ATLAS barrel toroid. Proposals for the magnet fabrication and assembly are given.

Superconducting toroid design for the ATLAS experiment at LHC

The ATLAS Experiment proposed for LHC will use toroidal magnet systems to achieve high muon momentum resolution. The proposal is based on an air-cored superconducting toroid magnet system consisting of a long barrel toroid with a pair of end cap toroids to provide high resolution at large rapidity. Each end cap toroid will have an outer diameter of approximately 11 m and an axial length of 5 m and will provide field integrals in the range 4-8 Tm over the rapidity span /spl eta/=1.5-2.8. This paper presents the magnetic, mechanical and cryogenic design of the end cap toroid magnet systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>