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Öğe Erratum to: Measurement of the top quark mass with lepton+jets final states using pp collisions at s = 13 TeV (The European Physical Journal C, (2018), 78, 11, (891), 10.1140/epjc/s10052-018-6332-9)(Springer Science and Business Media Deutschland GmbH, 2022) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.In this article the author name Luigi Calligaris was incorrectly written as A. Calligaris. The original article has been corrected. © CERN for the benefit of the CMS collaboration 2022.Öğe Erratum: Search for heavy Higgs bosons decaying to a top quark pair in proton-proton collisions at s = 13 TeV (Journal of High Energy Physics, (2020), 2020, 4, (171), 10.1007/JHEP04(2020)171)(Springer Science and Business Media Deutschland GmbH, 2022) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Dragicevic, M.In figure 7 of the original publication, the label of the y axis should have been (Formula presented.)”. The corrected version is shown in figure 1. Accordingly, the text pointing to the figure should read “figure 7 shows scans of (Formula presented.) for this hypothesis, as a function of the coupling modifier gAtt-”. © The Author(s).Öğe Evidence for collectivity in pp collisions at the LHC(Elsevier B.V., 2017) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.Measurements of two- and multi-particle angular correlations in pp collisions at s=5,7, and 13TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0pb−1 (5 TeV), 6.2pb−1 (7 TeV), and 0.7pb−1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of KS 0 and Λ/Λ‾ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), KS 0, and Λ/Λ‾, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT≈2GeV/c. For 13 TeV data, the v2 signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions. © 2016 The AuthorÖğe Measurement of Bc (2S)+ and Bc∗ (2S)+ cross section ratios in proton-proton collisions at s =13 TeV [2](American Physical Society, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; Erö, J.The ratios of the Bc(2S)+ to Bc+, Bc∗(2S)+ to Bc+, and Bc∗(2S)+ to Bc(2S)+ production cross sections are measured in proton-proton collisions at s=13 TeV, using a data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 143 fb-1. The three measurements are made in the Bc+ meson phase space region defined by the transverse momentum pT>15 GeV and absolute rapidity |y|<2.4, with the excited Bc(∗)(2S)+ states reconstructed through the Bc(∗)+π+π-, followed by the Bc+→J/ψπ+ and J/ψ→μ+μ- decays. The Bc(2S)+ to Bc+, Bc∗(2S)+ to Bc+, and Bc∗(2S)+ to Bc(2S)+ cross section ratios, including the unknown Bc(∗)(2S)+→Bc(∗)+π+π- branching fractions, are (3.47±0.63(stat)±0.33(syst))%, (4.69±0.71(stat)±0.56(syst))%, and 1.35±0.32(stat)±0.09(syst), respectively. None of these ratios shows a significant dependence on the pT or |y| of the Bc+ meson. The normalized dipion invariant mass distributions from the decays Bc(∗)(2S)+→Bc(∗)+π+π- are also reported. © 2020 CERN.Öğe Measurement of the Higgs boson production rate in association with top quarks in final states with electrons, muons, and hadronically decaying tau leptons at √s=13Te(Springer Science and Business Media Deutschland GmbH, 2021) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Valle, A. Escalante DelThe rate for Higgs (H) bosons production in association with either one (t H) or two (t t ¯ H) top quarks is measured in final states containing multiple electrons, muons, or tau leptons decaying to hadrons and a neutrino, using proton–proton collisions recorded at a center-of-mass energy of 13Te by the CMS experiment. The analyzed data correspond to an integrated luminosity of 137fb-1. The analysis is aimed at events that contain H → W W , H → τ τ , or H → Z Z decays and each of the top quark(s) decays either to lepton+jets or all-jet channels. Sensitivity to signal is maximized by including ten signatures in the analysis, depending on the lepton multiplicity. The separation among t H , t t ¯ H , and the backgrounds is enhanced through machine-learning techniques and matrix-element methods. The measured production rates for the t t ¯ H and t H signals correspond to 0.92±0.19(stat)-0.13+0.17(syst) and 5.7±2.7(stat)±3.0(syst) of their respective standard model (SM) expectations. The corresponding observed (expected) significance amounts to 4.7 (5.2) standard deviations for t t ¯ H , and to 1.4 (0.3) for t H production. Assuming that the Higgs boson coupling to the tau lepton is equal in strength to its expectation in the SM, the coupling yt of the Higgs boson to the top quark divided by its SM expectation, κt=yt/ytSM, is constrained to be within - 0.9 < κt< - 0.7 or 0.7 < κt< 1.1 , at 95% confidence level. This result is the most sensitive measurement of the t t ¯ H production rate to date. © 2021, CERN for the benefit of the CMS collaboration.Öğe Running of the top quark mass from proton-proton collisions at s=13TeV [2](Elsevier B.V., 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.The running of the top quark mass is experimentally investigated for the first time. The mass of the top quark in the modified minimal subtraction (MS‾) renormalization scheme is extracted from a comparison of the differential top quark-antiquark (tt¯) cross section as a function of the invariant mass of the tt¯ system to next-to-leading-order theoretical predictions. The differential cross section is determined at the parton level by means of a maximum-likelihood fit to distributions of final-state observables. The analysis is performed using tt¯ candidate events in the e± μ∓ channel in proton-proton collision data at a centre-of-mass energy of 13 TeV recorded by the CMS detector at the CERN LHC in 2016, corresponding to an integrated luminosity of 35.9fb−1. The extracted running is found to be compatible with the scale dependence predicted by the corresponding renormalization group equation. In this analysis, the running is probed up to a scale of the order of 1 TeV. © 2020 The Author(s)Öğe Search for decays of stopped exotic long-lived particles produced in proton-proton collisions at √s=13 TeV(Springer Verlag, 2018) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.A search is presented for the decays of heavy exotic long-lived particles (LLPs) that are produced in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC and come to rest in the CMS detector. Their decays would be visible during periods of time well separated from proton-proton collisions. Two decay scenarios of stopped LLPs are explored: a hadronic decay detected in the calorimeter and a decay into muons detected in the muon system. The calorimeter (muon) search covers a period of sensitivity totaling 721 (744) hours in 38.6 (39.0) fb−1 of data collected by the CMS detector in 2015 and 2016. The results are interpreted in several scenarios that predict LLPs. Production cross section limits are set as a function of the mean proper lifetime and the mass of the LLPs, for lifetimes between 100 ns and 10 days. These are the most stringent limits to date on the mass of hadronically decaying stopped LLPs, and this is the first search at the LHC for stopped LLPs that decay to muons.[Figure not available: see fulltext.]. © 2018, The Author(s).Öğe Search for t t ¯ H production in the H → b b ¯ decay channel with leptonic t t ¯ decays in proton-proton collisions at √s=13 TeV(Springer Verlag, 2019) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.A search is presented for the associated production of a standard model Higgs boson with a top quark-antiquark pair (t t ¯ H), in which the Higgs boson decays into a b quark-antiquark pair, in proton-proton collisions at a centre-of-mass energy s=13 TeV. The data correspond to an integrated luminosity of 35.9 fb −1 recorded with the CMS detector at the CERN LHC. Candidate t t ¯ H events are selected that contain either one or two electrons or muons from the t t ¯ decays and are categorised according to the number of jets. Multivariate techniques are employed to further classify the events and eventually discriminate between signal and background. The results are characterised by an observed t t ¯ H signal strength relative to the standard model cross section, μ = σ/σ SM, under the assumption of a Higgs boson mass of 125 GeV. A combined fit of multivariate discriminant distributions in all categories results in an observed (expected) upper limit on μ of 1.5 (0.9) at 95% confidence level, and a best fit value of 0.72 ± 0.24(stat) ± 0.38(syst), corresponding to an observed (expected) signal significance of 1.6 (2.2) standard deviations above the background-only hypothesis.[Figure not available: see fulltext.].Öğe Search for top quark partners with charge 5/3 in the same-sign dilepton and single-lepton final states in proton-proton collisions at √s=13 TeV(Springer Verlag, 2019) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.A search for the pair production of heavy fermionic partners of the top quark with charge 5/3 (X 5/3 ) is performed in proton-proton collisions at a center-of-mass energy of 13 TeV with the CMS detector at the CERN LHC. The data sample analyzed corresponds to an integrated luminosity of 35.9 fb −1 . The X 5/3 quark is assumed always to decay into a top quark and a W boson. Both the right-handed and left-handed X 5/3couplings to the W boson are considered. Final states with either a pair of same-sign leptons or a single lepton are studied. No significant excess of events is observed above the expected standard model background. Lower limits at 95% confidence level on the X 5/3 quark mass are set at 1.33 and 1.30 TeV respectively for the case of right-handed and left-handed couplings to W bosons in a combination of the same-sign dilepton and single-lepton final states.[Figure not available: see fulltext.]Öğe Search for Wγ resonances in proton-proton collisions at s=13 TeV using hadronic decays of Lorentz-boosted W bosons [2](Elsevier B.V., 2022) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.A search for Wγ resonances in the mass range between 0.7 and 6.0 TeV is presented. The W boson is reconstructed via its hadronic decays, with the final-state products forming a single large-radius jet, owing to a high Lorentz boost of the W boson. The search is based on proton-proton collision data at s=13 TeV, corresponding to an integrated luminosity of 137 fb−1, collected with the CMS detector at the LHC in 2016–2018. The Wγ mass spectrum is parameterized with a smoothly falling background function and examined for the presence of resonance-like signals. No significant excess above the predicted background is observed. Model-specific upper limits at 95% confidence level on the product of the cross section and branching fraction to the Wγ channel are set. Limits for narrow resonances and for resonances with an intrinsic width equal to 5% of their mass, for spin-0 and spin-1 hypotheses, range between 0.17 fb at 6.0 TeV and 55 fb at 0.7 TeV. These are the most restrictive limits to date on the existence of such resonances over a large range of probed masses. In specific heavy scalar (vector) triplet benchmark models, narrow resonances with masses between 0.75 (1.15) and 1.40 (1.36) TeV are excluded for a range of model parameters. Model-independent limits on the product of the cross section, signal acceptance, and branching fraction to the Wγ channel are set for minimum Wγ mass thresholds between 1.5 and 8.0 TeV. © 2022 The Author(s)Öğe Search for W′ bosons decaying to a top and a bottom quark at s=13TeV in the hadronic final state(Elsevier B.V., 2021) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; Erö, J.A search is performed for W′ bosons decaying to a top and a bottom quark in the all-hadronic final state, in proton-proton collisions at a center-of-mass energy of 13 TeV. The analyzed data were collected by the CMS experiment between 2016 and 2018 and correspond to an integrated luminosity of 137 fb−1. Deep neural network algorithms are used to identify the jet initiated by the bottom quark and the jet containing the decay products of the top quark when the W boson from the top quark decays hadronically. No excess above the estimated standard model background is observed. Upper limits on the production cross sections of W′ bosons decaying to a top and a bottom quark are set. Both left- and right-handed W′ bosons with masses below 3.4 TeV are excluded at 95% confidence level, and the most stringent limits to date on W′ bosons decaying to a top and a bottom quark in the all-hadronic final state are obtained. © 2021 The Author(s)Öğe Study of J/ψ meson production inside jets in pp collisions at s=8TeV [2](Elsevier B.V., 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Dragicevic, M.A study of the production of prompt J/ψ mesons contained in jets in proton-proton collisions at s=8TeV is presented. The analysis is based on data corresponding to an integrated luminosity of 19.1 fb−1 collected with the CMS detector at the LHC. For events with at least one observed jet, the angular separation between the J/ψ meson and the jet is used to test whether the J/ψ meson is part of the jet. The analysis shows that most prompt J/ψ mesons having energy above 15 GeV and rapidity |y|<1 are contained in jets with pseudorapidity |ηjet|<1. The differential distributions of the probability to have a J/ψ meson contained in a jet as a function of jet energy for a fixed J/ψ energy fraction are compared to a theoretical model using the fragmenting jet function approach. The data agree best with fragmenting jet function calculations that use a long-distance matrix element parameter set in which prompt J/ψ mesons are predicted to be unpolarized. This technique demonstrates a new way to test predictions for prompt J/ψ production using nonrelativistic quantum chromodynamics. © 2020 Elsevier B.V.
