Measurement of the transverse momentum spectrum of the Higgs boson produced in pp collisions at \( \sqrt{s}=8 \) TeV using H → WW decays

Journal of High Energy Physics, Mar 2017

The cross section for Higgs boson production in pp collisions is studied using the H → W+W− decay mode, followed by leptonic decays of the W bosons to an oppositely charged electron-muon pair in the final state. The measurements are performed using data collected by the CMS experiment at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.4 fb−1. The Higgs boson transverse momentum (p T) is reconstructed using the lepton pair p T and missing p T. The differential cross section times branching fraction is measured as a function of the Higgs boson p T in a fiducial phase space defined to match the experimental acceptance in terms of the lepton kinematics and event topology. The production cross section times branching fraction in the fiducial phase space is measured to be 39 ± 8 (stat) ± 9 (syst) fb. The measurements are found to agree, within experimental uncertainties, with theoretical calculations based on the standard model.

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Measurement of the transverse momentum spectrum of the Higgs boson produced in pp collisions at \( \sqrt{s}=8 \) TeV using H → WW decays

Received: June decays The CMS collaboration 0 1 2 3 4 5 0 [56] S. Alioli , P. Nason, C. Oleari and E. Re, NLO Higgs boson production via gluon fusion 1 Chulalongkorn University, Faculty of Science, Department of Physics , Bangkok 2 State University of New York at Bu alo , Bu alo , U.S.A 3 (MEPhI) , Moscow , Russia 4 15: Also at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University 5 59: Also at Istanbul Bilgi University , Istanbul , Turkey The cross section for Higgs boson production in pp collisions is studied using Hadron-Hadron scattering (experiments); Higgs physics - decay mode, followed by leptonic decays of the W bosons to an oppositely charged electron-muon pair in the nal state. The measurements are performed using data collected by the CMS experiment at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.4 fb 1. The Higgs boson transverse momentum (pT) is reconstructed using the lepton pair pT and missing pT. The di erential cross section times branching fraction is measured as a function of the Higgs boson pT in a ducial phase space de ned to match the experimental acceptance in terms of the lepton kinematics and event topology. The production cross section times branching fraction in ducial phase space is measured to be 39 9 (syst) fb. The measurements are found to agree, within experimental uncertainties, with theoretical calculations based on the standard model. 1 Introduction The CMS experiment Data and simulated samples Analysis strategy Background estimation Systematic uncertainties Signal extraction The CMS collaboration Unfolding and treatment of systematic uncertainties The discovery of a new boson at the CERN LHC reported by the ATLAS and CMS collaborations [1{3] has been followed by a comprehensive set of measurements aimed at establishing the properties of the new boson. Results reported by ATLAS and CMS [4{22], so far, are consistent with the standard model (SM) expectations for the Higgs boson (H). Measurements of the production cross section of the Higgs boson times branching fraction in a restricted part of the phase space ( ducial phase space) and its kinematic properties represent an important test for possible deviations from the SM predictions. In particular, it has been shown that the Higgs boson transverse momentum (pTH) spectrum can be signi cantly a ected by the presence of interactions not predicted by the SM [23{27]. In addition, these measurements allow accurate tests of the theoretical calculations in the SM Higgs sector, which o er up to next-to-next-to-leading-order (NNLO) accuracy in perturbative Quantum ChromoDynamics (pQCD), up to next-to-next-to-leading-logarithmic (NNLL) accuracy in the resummation of soft-gluon e ects at small pT, and up to next-toleading-order (NLO) accuracy in perturbative electroweak corrections [28{30]. Measurements of the ducial cross sections and of several di erential distributions, for the H ! ZZ ! 4` (` = e; ) and H ! decay channels, and recently by ATLAS [36] decay channel. In this paper we report a measurement of the ducial cross section times branching fraction ( production in H ! W+W decays, based on p B) and pT spectrum for Higgs boson s = 8 TeV LHC data. The analysis is performed looking at di erent avour leptons in the nal state in order to suppress the sizeable contribution of backgrounds containing a same- avour lepton pair originating from Z boson decay. Although the H ! W+W the pTH measurement compared to the H ! ! 2`2 channel has lower resolution in and H ! ZZ ! 4` channels because of neutrinos in the nal state, the channel has a signi cantly larger B, exceeding those for by a factor of 10 and H ! ZZ ! 4` by a factor of 85 for a Higgs boson mass of 125 GeV [37], and is characterized by good signal sensitivity. Such sensitivity allowed the observation of a Higgs boson at the level of 4.3 (5.8 expected) standard deviations for a mass hypothesis of 125.6 GeV using the full LHC data set at 7 and 8 TeV [7]. The measurement is performed in a ducial phase space de ned by kinematic requirements on the leptons that closely match the experimental event selection. The e ect of the limited detector resolution, as well as the selection e ciency with respect to the phase space are corrected to particle level with an unfolding procedure [38]. This procedure is based on the knowledge of the detector response matrix, derived from the simulation of the CMS response to signal events, and consists of an inversion of the response matrix with a regularization prescription to tame unphysical statistical uctuations in the unfolded result. The analysis presented here is based on the previously published H ! W+W measurements by CMS [7]. A notable di erence from those measurements is that this analysis is inclusive in the number of jets, which allows the uncertainties related to the theoretical modelling of additional jets produced in association with the Higgs boson to b (...truncated)


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V. Khachatryan, A. M. Sirunyan, A. Tumasyan, W. Adam. Measurement of the transverse momentum spectrum of the Higgs boson produced in pp collisions at \( \sqrt{s}=8 \) TeV using H → WW decays, Journal of High Energy Physics, 2017, pp. 32, Volume 2017, Issue 3, DOI: 10.1007/JHEP03(2017)032