Suche
Ergebnisse
-
Mechanical stability of the CMS strip tracker measured with a laser alignment system
(2017)Journal of InstrumentationThe CMS tracker consists of 206 m2 of silicon strip sensors assembled on carbon fibre composite structures and is designed for operation in the temperature range from −25 to +25°C. The mechanical stability of tracker components during physics operation was monitored with a few μm resolution using a dedicated laser alignment system as well as particle tracks from cosmic rays and hadron-hadron collisions. During the LHC operational period ...Journal Article -
Measurement of the top quark mass using proton-proton data at √s = 7 and 8 TeV
(2016)Physical Review DA new set of measurements of the top quark mass are presented, based on the proton-proton data recorded by the CMS experiment at the LHC at √s = 8 TeV corresponding to a luminosity of 19.7fb−1. The top quark mass is measured using the lepton + jets, all-jets and dilepton decay channels, giving values of 172.35 ± 0.16(stat) ± 0.48(syst) GeV, 172.32 ± 0.25(stat) ± 0.59(syst) GeV, and 172.82 ± 0.19(stat) ± 1.22(syst) GeV, respectively. When ...Journal Article -
Search for dark matter and unparticles produced in association with a Z boson in proton-proton collisions at √s = 8 TeV
(2016)Physical Review DA search for evidence of particle dark matter (DM) and unparticle production at the LHC has been performed using events containing two charged leptons, consistent with the decay of a Z boson, and large missing transverse momentum. This study is based on data collected with the CMS detector corresponding to an integrated luminosity of 19.7 fb−1 of pp collisions at the LHC at a center-of-mass energy of 8 TeV. No significant excess of events ...Journal Article -
Measurement of the Electron Charge Asymmetry in Inclusive W Production in pp Collisions at √s=7 TeV
(2012)Physical Review LettersA measurement of the electron charge asymmetry in inclusive pp→W+X→eν+X production at √s=7 TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 840 pb−1. The electron charge asymmetry reflects the unequal production of W+ and W− bosons in pp collisions. The electron charge asymmetry is measured in bins of the absolute value of electron pseudorapidity in the range of ...Journal Article -
Measurement of the t-Channel Single Top Quark Production Cross Section in pp Collisions at √s=7 TeV
(2011)Physical Review LettersElectroweak production of the top quark is measured for the first time in pp collisions at √s=7 TeV, using a data set collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 pb−1. With an event selection optimized for t-channel production, two complementary analyses are performed. The first one exploits the special angular properties of the signal, together with background estimates from the data. ...Journal Article -
Calibration of the CMS hadron calorimeters using proton-proton collision data at √s = 13 TeV
(2020)Journal of InstrumentationMethods are presented for calibrating the hadron calorimeter system of the CMS detector at the LHC. The hadron calorimeters of the CMS experiment are sampling calorimeters of brass and scintillator, and are in the form of one central detector and two endcaps. These calorimeters cover pseudorapidities |η| < 3 and are positioned inside the solenoidal magnet. An outer calorimeter, outside the magnet coil, covers |η| < 1.26, and a steel and ...Journal Article -
Measurement of the t¯t production cross section in pp collisions at √s=7 TeV in dilepton final states containing a τ
(2012)Physical Review DThe top quark pair production cross section is measured in dilepton events with one electron or muon, and one hadronically decaying τ lepton from the decay t¯t→(ℓνℓ)(τhντ)b¯b, (ℓ=e,μ). The data sample corresponds to an integrated luminosity of 2.0 fb−1 for the electron channel and 2.2 fb−1 for the muon channel, collected by the CMS detector at the LHC. This is the first measurement of the t¯t cross section explicitly including τ leptons ...Journal Article -
Measurement of the integrated and differential t¯t production cross sections for high-pT top quarks in pp collisions at √s=8 TeV
(2016)Physical Review DThe cross section for pair production of top quarks (t¯t) with high transverse momenta is measured in pp collisions, collected with the CMS detector at the LHC with √s=8 TeV in data corresponding to an integrated luminosity of 19.7 fb−1. The measurement is performed using lepton+jets events, where one top quark decays semileptonically, while the second top quark decays to a hadronic final state. The hadronic decay is reconstructed as a ...Journal Article