9,710 research outputs found
Measurement of associated W+ charm production in pp collisions at √s=7 TeV
No full textOpen Access, Copyright CERN, for the benefit of the CMS Collaboration.Measurements are presented of the associated production of a W boson and a charm-quark jet (W + c) in pp collisions at a center-of-mass energy of 7 TeV. The analysis is conducted with a data sample corresponding to a total integrated luminosity of 5 fb−1, collected by the CMS detector at the LHC. W boson candidates are identified by their decay into a charged lepton (muon or electron) and a neutrino. The W + c measurements are performed for charm-quark jets in the kinematic region p jet T > 25 GeV, |ηjet| 25 GeV) and σ(pp → W + c + X)× B (W → ℓν) = 84.1 ± 2.0 (stat.) ± 4.9 (syst.) pb ( p ℓ T > 35 GeV), and the cross section ratios σ(pp → W+ + c ¯ + X)/σ(pp → W− + c + X) = 0.954 ± 0.025 (stat.) ± 0.004 (syst.) ( p ℓ T > 25 GeV) and σ(pp → W+ + c ¯ + X)/σ(pp → W− + c + X) = 0.938 ± 0.019 (stat.) ± 0.006 (syst.) ( p ℓ T > 35 GeV). Cross sections and cross section ratios are also measured differentially with respect to the absolute value of the pseudorapidity of the lepton from the W-boson decay. These are the first measurements from the LHC directly sensitive to the strange quark and antiquark content of the proton. Results are compared with theoretical predictions and are consistent with the predictions based on global fits of parton distribution functions
Measurements of Production Cross Sections of Polarized Same-Sign W Boson Pairs in Association With Two Jets in Proton-Proton Collisions at S=13 Tev
No full textThe first measurements of production cross sections of polarized same-sign W±W± boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 137fb−1. Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign W±W± scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88) fbis set on the production cross section for longitudinally polarized same-sign W±W± boson pairs. The electroweak production of same-sign W±W± boson pairs with at least one of the W bosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations. © 2020 The Author(s
Characterisation of irradiated thin silicon sensors for the CMS phase II pixel upgrade
No full textThe high luminosity upgrade of the Large Hadron Collider, foreseen for 2026, necessitates the replacement of the CMS experiment’s silicon tracker. The innermost layer of the new pixel detector will be exposed to severe radiation, corresponding to a 1 MeV neutron equivalent fluence of up to Φeq=2×1016 cm−2, and an ionising dose of ≈5 MGy after an integrated luminosity of 3000 fb−1. Thin, planar silicon sensors are good candidates for this application, since the degradation of the signal produced by traversing particles is less severe than for thicker devices. In this paper, the results obtained from the characterisation of 100 and 200 μm thick p-bulk pad diodes and strip sensors irradiated up to fluences of Φeq=1.3×1016 cm−2 are shown
Search for the associated production of the Higgs boson with a top-quark pair (vol 9, 087, 2014): Erratum
No full textErratum to: JHEP09(2014)087Khachatryan, V., Sirunyan, AM., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M., Ero, J., Fabjan, C., Friedl, M., Fruhwirth, R., Ghete, VM., Hartl, C., Hormann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knunz, V., Krammer, M., Kratschmer, I., Liko, D., Mikulec, I., Rabady, D., Rahbaran, B., Rohringer, H., Schofbeck, R., Strauss, J., Taurok, A., Treberer-Treberspurg, W., The CMS Collaboratio
Measurement of associated production of a W boson and a charm quark in proton–proton collisions at √s=13Te
No full text© 2019, CERN for the benefit of the CMS collaboration. Measurements are presented of associated production of a W boson and a charm quark (W + c) in proton–proton collisions at a center-of-mass energy of 13Te. The data correspond to an integrated luminosity of 35.7fb-1 collected by the CMS experiment at the CERN LHC. The W bosons are identified by their decay into a muon and a neutrino. The charm quarks are tagged via the full reconstruction of D ∗ (2010) ± mesons that decay via D ∗ (2010) ± → D + π ± → K ∓ + π ± + π ± . A cross section is measured in the fiducial region defined by the muon transverse momentum pTμ>26Ge, muon pseudorapidity | η μ | 5Ge. The inclusive cross section for this kinematic range is σ(W+c)=1026±31(stat)+76-72(syst) pb. The cross section is also measured differentially as a function of the pseudorapidity of the muon from the W boson decay. These measurements are compared with theoretical predictions and are used to probe the strange quark content of the proton
Measurement of the muon charge asymmetry in inclusive pp →w+X production at s =7TeV and an improved determination of light parton distribution functions
No full textMeasurements of the muon charge asymmetry in inclusive pp→W+X production at s=7TeV are presented. The data sample corresponds to an integrated luminosity of 4.7fb-1 recorded with the CMS detector at the LHC. With a sample of more than 20 million W→μν events, the statistical precision is greatly improved in comparison to previous measurements. These new results provide additional constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10-3 to 10-1. These measurements and the recent CMS measurement of associated W+charm production are used together with the cross sections for inclusive deep inelastic e±p scattering at HERA in a next-to-leading-order QCD analysis. The determination of the valence quark distributions is improved, and the strange-quark distribution is probed directly through the leading-order process g+s→W+c in proton-proton collisions at the LHC. © 2014 CERN, for the CMS Collaboration
Measurement of electroweak production of a W boson and two forward jets in proton-proton collisions at ?s = 8 TeV
No full textA measurement is presented of the cross section for the electroweak production of a W boson in association with two jets in proton-proton collisions at a center-of-mass energy of 8 TeV. The data set was collected with the CMS detector and corresponds to an integrated luminosity of 19.3 fb?1. The measured fiducial cross section for W bosons decaying to electrons or muons and for pT j1> 60 GeV, pT j2> 50 GeV, |?j| < 4.7, and mjj> 1000 GeV is 0.42 ± 0.04 (stat) ± 0.09 (syst) ± 0.01 (lumi) pb. This result is consistent with the standard model leading-order prediction of 0.50 ± 0.02 (scale) ± 0.02 (PDF) pb obtained with MadGraph5_amc@nlo 2.1 interfaced to pythia 6.4. This is the first cross section measurement for this process. © 2016, The Author(s).National Science Foundation, NSF: 1120138, 1151640, 1211067, 1401984, 1506130, 1506168, 1508869, 1606321; National Science Foundation, NSF; Science and Technology Facilities Council, STFC: GRIDPP, ST/K001256/1, ST/N000242/1, ST/N000250/1; Science and Technology Facilities Council, STF
Measurement of the production cross section for a W boson in association with a charm quark in proton–proton collisions at ?s=13TeV
No full textThe strange quark content of the proton is probed through the measurement of the production cross section for a W boson and a charm (c) quark in proton–proton collisions at a center-of-mass energy of 13 TeV . The analysis uses a data sample corresponding to a total integrated luminosity of 138 fb-1 collected with the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm jets are tagged using the presence of a muon or a secondary vertex inside the jet. The W + c production cross section and the cross section ratio Rc±=?(W++c¯)/?(W-+c) are measured inclusively and differentially as functions of the transverse momentum and the pseudorapidity of the lepton originating from the W boson decay. The precision of the measurements is improved with respect to previous studies, reaching 1% in Rc±=0.950±0.005(stat)±0.010(syst) . The measurements are compared with theoretical predictions up to next-to-next-to-leading order in perturbative quantum chromodynamics. © 2024, The Author(s)
Measurement of electroweak production of a W boson in association with two jets in proton–proton collisions at √s=13Te
No full text© 2020, CERN for the benefit of the CMS collaboration.A measurement is presented of electroweak (EW) production of a W boson in association with two jets in proton–proton collisions at s=13Te. The data sample was recorded by the CMS Collaboration at the LHC and corresponds to an integrated luminosity of 35.9fb-1. The measurement is performed for the ℓνjj final state (with ℓν indicating a lepton–neutrino pair, and j representing the quarks produced in the hard interaction) in a kinematic region defined by invariant mass mjj>120Ge and transverse momenta pTj>25Ge. The cross section of the process is measured in the electron and muon channels yielding σEW(Wjj)=6.23±0.12(stat)±0.61(syst)pb per channel, in agreement with leading-order standard model predictions. The additional hadronic activity of events in a signal-enriched region is studied, and the measurements are compared with predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. Limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are -2.3<cWWW/Λ2<2.5Te-2, -8.8<cW/Λ2<16Te-2, and -45<cB/Λ2<46Te-2. These results are combined with the CMS EW Zjj analysis, yielding the constraint on the cW W W coupling: -1.8<cWWW/Λ2<2.0Te-2
Search for the standard model Higgs boson produced in association with W and Z bosons in pp collisions at √s=7 TeV
No full textChatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Aguilo, E., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C., Friedl, M., Frühwirth, R., Ghete, V.M., Hammer, J., Hörmann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knünz, V., Krammer, M., Liko, D., Mikulec, I., Pernicka, M., Rahbaran, B., Rohringer, C., Rohringer, H., Schöfbeck, R., Strauss, J., Taurok, A., Waltenberger, W., Walzel, G., Widl, E., Wulz, C.-E., Mossolov, V., Shumeiko, N., Suarez Gonzalez, J., Bansal, S., Cornelis, T., De Wolf, E.A., Janssen, X., Luyckx, S., Mucibello, L., Ochesanu, S., Roland, B., Rougny, R., Selvaggi, M., Staykova, Z., Van Haevermaet, H., Van Mechelen, P., Van Remortel, N., Van Spilbeeck, A., Blekman, F., Blyweert, S., D'Hondt, J., Gonzalez Suarez, R., Kalogeropoulos, A., Maes, M., Olbrechts, A., Van Doninck, W., Van Mulders, P., Van Onsem, G.P., Villella, I., Clerbaux, B., De Lentdecker, G., Dero, V., Gay, A.P.R., Hreus, T., Léonard, A., Marage, P.E., Reis, T., Thomas, L., Vander Velde, C., Vanlaer, P., Wang, J., Adler, V., Beernaert, K., Cimmino, A., Costantini, S., Garcia, G., Grunewald, M., Klein, B., Lellouch, J., Marinov, A., McCartin, J., Ocampo Rios, A.A., Ryckbosch, D., Strobbe, N., Thyssen, F., Tytgat, M., Verwilligen, P., Walsh, S., Yazgan, E., Zaganidis, N., Basegmez, S., Bruno, G., Castello, R., Ceard, L., Delaere, C., Du Pree, T., Favart, D
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