4,836 research outputs found
Messung der Rate des CP-verletzenden Zerfalls des langlebigen neutralen Kaons in zwei neutrale Pionen durch Vergleich zu dem erlaubten in drei neutrale Pionen
No full textThe network of photodetectors and diode lasers of the CMS Link alignment system
Get PDFArce, P., Barcala, J.M., Calvo, E., Ferrando, A., Josa, M.I., Molinero, A., Navarrete, J., Oller, J.C., Brochero, J., Calderón, A., Fernández, M.G., Gómez, G., González-Sánchez, F.J., Martínez-Rivero, C., Matorras, F., Rodrigo, T., Ruiz-Árbol, P., Scodellaro, L., Sobrón, M., Vila, I., Virto, A.L., Fernández, J., Raics, P., Szabó, Z., Trócsnyi, Z., Ujvári, B., Zilizi, G., Béni, N., Christian, G., Imrek, J., Molnar, J., Novak, D., Pálinkás, J., Székely, G., Szillási, Z., Bencze, G.L., Vestergombi, G., Benettoni, M., Gasparini, F., Montecassiano, F., Rampazzo, M., Zago, M., Benvenuti, A., Reithler, H., Jiang, C
Offline calibration procedure of the CMS Drift Tube detectors
No full textAbbiendi, G., Amapane, N., Battilana, C., Bellan, R., Biallass, P., Biasotto, M., Bolognesi, S., Calderon Tazon, A., Cavallo, F.R., Cepeda, M., Cerminara, G., De La Cruz, B., Diez Pardos, C., Fernandez Bedoya, C., Fernandez Menendez, J., Fouz Iglesias, M.C., Frangenheim, J., Giunta, M., Gresele, A., Guiducci, L., Gulmini, M., Hoepfner, K., Josa Mutuberria, M.I., Lacaprara, S., Marcellini, S., Martinez Ruiz Del Arbol, P., Maselli, S., Masetti, G., Meneguzzo, A.T., Mila, G., Molina Insfran, J.A., Passaseo, M., Perrotta, A., Puerta Pelayo, J., Reithler, H., Ronchese, P., Rovelli, T., Santaolalla Camino, J., Teyssier, D., Travaglini, R., Trocino, D., Vanini, S., Ventura, S., Vilela Pereira, A., Zanetti, M
Simulations in the development of the barrel muon chambers for CMS detector at LHC
No full textThe development of the barrel drift chambers for the CMS muon detector at the CERN Large Hadron Collider is supported by a variety of simulation calculations, based on the GARFIELD drift chamber simulation program and the GEANT detector simulation package. This study surveys the results influencing the actual chamber design. The dependence of the drift cell performance on shape and position of the cell electrodes as well as on the mechanical tolerances is shown. The results obtained for space-time relation and spatial resolution are in good agreement to test beam measurements on prototypes. (C) 1998 Elsevier Science B.V. All rights reserved
Measurement of the t t ¯ H and tH production rates in the H → b b ¯ decay channel using proton-proton collision data at s = 13 TeV
No full textAbstract An analysis of the production of a Higgs boson (H) in association with a top quark-antiquark pair ( t t ¯ H ) or a single top quark (tH) is presented. The Higgs boson decay into a bottom quark-antiquark pair (H → b b ¯ ) is targeted, and three different final states of the top quark decays are considered, defined by the number of leptons (electrons or muons) in the event. The analysis utilises proton-proton collision data collected at the CERN LHC with the CMS experiment at s = 13 TeV in 2016–2018, which correspond to an integrated luminosity of 138 fb −1. The observed t t ¯ H production rate relative to the standard model expectation is 0.33 ± 0.26 = 0.33 ± 0.17(stat) ± 0.21(syst). Additionally, the t t ¯ H production rate is determined in intervals of Higgs boson transverse momentum. An upper limit at 95% confidence level is set on the tH production rate of 14.6 times the standard model prediction, with an expectation of 19.3 − 6.0 + 9.2 . Finally, constraints are derived on the strength and structure of the coupling between the Higgs boson and the top quark from simultaneous extraction of the t t ¯ H and tH production rates, and the results are combined with those obtained in other Higgs boson decay channels
Combined search for anomalous pseudoscalar HW couplings in VH(H -> b(b)over-bar) production and H -> VV decay
No full textA search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (= W or Z) in a sample of proton-proton collision events corresponding to an integrated luminosity of 18.9 fb(-1) at a center-of-mass energy of 8 TeV is presented. Events consistent with the topology of associated VH production, where the Higgs boson decays to a pair of bottom quarks and the vector boson decays leptonically, are analyzed. The consistency of data with a potential pseudoscalar contribution to the HVV interaction, expressed by the effective pseudoscalar cross section fractions f(a3), is assessed by means of profile likelihood scans. Results are given for the VH channels alone and for a combined analysis of the VH and previously published H -> VV channels. Under certain assumptions, f(a3)(ZZ) > 0.0034 is excluded at 95% confidence level in the combination. Scenarios in which these assumptions are relaxed are also considered. (C) 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Evidence for the 125 GeV Higgs boson decaying to a pair of τ leptons
Get PDFOpen Access. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.A search for a standard model Higgs boson decaying into a pair of τ leptons is performed using events recorded by the CMS experiment at the LHC in 2011 and 2012. The dataset corresponds to an integrated luminosity of 4.9 fb−1 at a centre-of-mass energy of 7 TeV and 19.7 fb−1 at 8 TeV. Each τ lepton decays hadronically or leptonically to an electron or a muon, leading to six different final states for the τ -lepton pair, all considered in this analysis. An excess of events is observed over the expected background contributions, with a local significance larger than 3 standard deviations for m H values between 115 and 130 GeV. The best fit of the observed H → τ τ signal cross section times branching fraction for m H = 125 GeV is 0.78 ± 0.27 times the standard model expectation. These observations constitute evidence for the 125 GeV Higgs boson decaying to a pair of τ leptons
Combined search for anomalous pseudoscalar HVV couplings in VH(H→bb‾) production and H → VV decay
Get PDFA search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (=W or Z) in a sample of proton–proton collision events corresponding to an integrated luminosity of 18.9 fb−1 at a center-of-mass energy of 8 TeV is presented. Events consistent with the topology of associated VH production, where the Higgs boson decays to a pair of bottom quarks and the vector boson decays leptonically, are analyzed. The consistency of data with a potential pseudoscalar contribution to the HVV interaction, expressed by the effective pseudoscalar cross section fractions fa3, is assessed by means of profile likelihood scans. Results are given for the VH channels alone and for a combined analysis of the VH and previously published H→VV channels. Under certain assumptions, fa3ZZ>0.0034 is excluded at 95% confidence level in the combination. Scenarios in which these assumptions are relaxed are also considered
Studies of dijet transverse momentum balance and pseudorapidity distributions in pPb collisions at √sNN=5.02 TeV
Get PDFOpen Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the
source are credited. Funded by SCOAP3 / License Version CC BY 4.0.Dijet production has been measured in pPb collisions at a nucleon–nucleon centre-of-mass energy of 5.02 TeV . A data sample corresponding to an integrated luminosity of 35 nb −1 was collected using the Compact Muon Solenoid detector at the Large Hadron Collider. The dijet transverse momentum balance, azimuthal angle correlations, and pseudorapidity distributions are studied as a function of the transverse energy in the forward calorimeters ( E 4<|η|<5.2 T ). For pPb collisions, the dijet transverse momentum ratio and the width of the distribution of dijet azimuthal angle difference are comparable to the same quantities obtained from a simulated pp reference and insensitive to E 4<|η|<5.2 T . In contrast, the mean value of the dijet pseudorapidity is found to change monotonically with increasing E 4<|η|<5.2 T , indicating a correlation between the energy emitted at large pseudorapidity and the longitudinal motion of the dijet frame. The pseudorapidity distribution of the dijet system in minimum bias pPb collisions is compared with next-to-leading-order perturbative QCD predictions obtained from both nucleon and nuclear parton distribution functions, and the data more closely match the latter
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