879 research outputs found

    Measurement of the inclusive and differential t/t cross sections at 13 TeV in the all-jets boosted regime with CMS

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    The t/t production cross section is measured with the CMS detector in the all-jets channel in pppp collisions at the centre-of-mass energy of 13 TeV. The analysis is based on the study of t/t events in the boosted topology, namely events in which decay products of the quark top have a high Lorentz boost and are thus reconstructed in the detector as a single, wide jet. The data sample used in this analysis corresponds to an integrated luminosity of 2.53 fb-1. The inclusive cross section is found to be sigma(t/t) = 727 +- 46 (stat.) +115-112 (sys.) +- 20~(lumi.) pb, a value which is consistent with the theoretical predictions. The differential, detector-level cross section is measured as a function of the transverse momentum of the leading jet and compared to the QCD theoretical predictions. Finally, the differential, parton-level cross section is reported, measured as a function of the transverse momentum of the leading parton, extrapolated to the full phase space and compared to the QCD predictions

    Search for ttH(bb) events at 13 TeV in the fully hadronic final state targeting large-radius jets and a resolved decay of the Higgs boson with the CMS experiment

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    A search for ttH(bb) events in the fully hadronic final state is performed using data collected by the CMS experiment in proton-proton collisions at the center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 inverse femtobarns. The analysis is based on the study of events in the boosted topology, i.e., events in which the decay products of at least one particle have a high Lorentz boost and are thus reconstructed in the detector as a single, large-radius jet. In this search, the Higgs boson is required to decay to a pair of well-separated jets. The observed (expected) upper limit at 95% confidence level on the signal strength parameter, defined as the ratio of the measured ttH production cross section to the one expected from a standard model Higgs boson, is found to be 11.5 (15.8) times the expectation from the standard model. By performing a combination with a complementary search targeting decays of the Higgs boson to a large-radius jet, the observed (expected) upper limit at 95% confidence level on the signal strength parameter is found to be 7.1 (9.0) times the expectation from the standard model

    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV