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  • Erratum
    Citation - WoS: 3
    Citation - Scopus: 7
    Searches for Long-Lived Charged Particles in Pp Collisions at Root S = 7 and 8 Tev (vol 07, 122, 2013)
    (Springer, 2022) Karapınar, Güler; CMS Collaboration
    [No abstract available]
  • Correction
    Citation - Scopus: 3
  • Article
    Citation - WoS: 28
    Citation - Scopus: 33
    Search for Low-Mass Dilepton Resonances in Higgs Boson Decays To Four-Lepton Final States in Proton-Proton Collisions at Root S=13 Tev
    (Springer, 2022) Karapınar, Güler; CMS Collaboration
    A search for low-mass dilepton resonances in Higgs boson decays is conducted in the four-lepton final state. The decay is assumed to proceed via a pair of beyond the standard model particles, or one such particle and a Z boson. The search uses proton-proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1), at a center-of-mass energy root s = 13 TeV. No significant deviation from the standard model expectation is observed. Upper limits at 95% confidence level are set on model-independent Higgs boson decay branching fractions. Additionally, limits on dark photon and axion-like particle production, based on two specific models, are reported.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 13
    Search for a W' Boson Decaying To a Vector-Like Quark and a Top or Bottom Quark in the All-Jets Final State at Root S=13 Tev
    (Springer, 2022) Tumasyan, A.; Karapınar, Güler
    A search is presented for a heavy W' boson resonance decaying to a B or T vector-like quark and a t or a b quark, respectively. The analysis is performed using protonproton collisions collected with the CMS detector at the LHC. The data correspond to an integrated luminosity of 138 fb(-1) at a center-of-mass energy of 13 TeV. Both decay channels result in a signature with a t quark, a Higgs or Z boson, and a b quark, each produced with a significant Lorentz boost. The all-hadronic decays of the Higgs or Z boson and of the t quark are selected using jet substructure techniques to reduce standard model backgrounds, resulting in a distinct three-jet W boson decay signature. No significant deviation in data with respect to the standard model background prediction is observed. Upper limits are set at 95% confidence level on the product of the W' boson cross section and the final state branching fraction. A W boson with a mass below 3.1 TeV is excluded, given the benchmark model assumption of democratic branching fractions. In addition, limits are set based on generalizations of these assumptions. These are the most sensitive limits to date for this final state.
  • Article
    Citation - WoS: 34
    Citation - Scopus: 49
    Measurement of the Inclusive and Differential Wz Production Cross Sections, Polarization Angles, and Triple Gauge Couplings in Pp Collisions at Root S=13 Tev
    (Springer, 2022) Tumasyan, A.; Karapınar, Güler
    The associated production of a W and a Z boson is studied in final states with multiple leptons produced in proton-proton (pp) collisions at a centre-of-mass energy of 13 TeV using 137 fb(-1) of data collected with the CMS detector at the LHC. A measurement of the total inclusive production cross section yields sigma(tot)(pp -> WZ) = 50.6 +/- 0.8 (stat) +/- 1.5 (syst) +/- 1.1 (lumi) +/- 0.5 (theo) pb. Measurements of the fiducial and differential cross sections for several key observables are also performed in all the final-state lepton flavour and charge compositions with a total of three charged leptons, which can be electrons or muons. All results are compared with theoretical predictions computed up to next-to-next-to-leading order in quantum chromodynamics plus next-to-leading order in electroweak theory and for various sets of parton distribution functions. The results include direct measurements of the charge asymmetry and the W and Z vector boson polarization. The first observation of longitudinally polarized W bosons in WZ production is reported. Anomalous gauge couplings are searched for, leading to new constraints on beyond-the-standard-model contributions to the WZ triple gauge coupling.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 19
    Search for Charged-Lepton Flavor Violation in Top Quark Production and Decay in Pp Collisions at Root S=13 Tev
    (Springer, 2022) Tumasyan, A.; Karapınar, Güler
    Results are presented from a search for charged-lepton flavor violating (CLFV) interactions in top quark production and decay in pp collisions at a center-of-mass energy of 13 TeV. The events are required to contain one oppositely charged electron-muon pair in the final state, along with at least one jet identified as originating from a bottom quark. The data correspond to an integrated luminosity of 138 fb(-1), collected by the CMS experiment at the LHC. This analysis includes both the production (q -> e mu t) and decay (t -> e mu q) modes of the top quark through CLFV interactions, with q referring to a u or c quark. These interactions are parametrized using an effective field theory approach. With no significant excess over the standard model expectation, the results are interpreted in terms of vector-, scalar-, and tensor-like CLFV four-fermion effective interactions. Finally, observed exclusion limits are set at 95% confidence levels on the respective branching fractions of a top quark to an e mu pair and an up (charm) quark of 0.13 x 10(-6) (1.31 x 10(-6)), 0.07 x 10(-6) (0.89 x 10(-6)), and 0.25 x 10(-6) (2.59 x 10(-6)) for vector, scalar, and tensor CLFV interactions, respectively.
  • Article
    Citation - WoS: 23
    Citation - Scopus: 54
    Search for Electroweak Production of Charginos and Neutralinos in Proton-Proton Collisions at Root S=13 Tev
    (Springer, 2022) Tumasyan, A.; Karapınar, Güler
    A direct search for electroweak production of charginos and neutralinos is presented. Events with three or four leptons, with up to two hadronically decaying tau leptons, or two same-sign light leptons are analyzed. The data sample consists of 137 fb(-1) of proton-proton collisions with a center of mass energy of 13 TeV, recorded with the CMS detector at the LHC. The results are interpreted in terms of several simplified models. These represent a broad range of production and decay scenarios for charginos and neutralinos. A parametric neural network is used to target several of the models with large backgrounds. In addition, results using orthogonal search regions are provided for all the models, simplifying alternative theoretical interpretations of the results. Depending on the model hypotheses, charginos and neutralinos with masses up to values between 300 and 1450 GeV are excluded at 95% confidence level.
  • Article
    Citation - WoS: 11
    Citation - Scopus: 16
    Measurement of the Inclusive T(t)over-Bar Production Cross Section in Proton-Proton Collisions at Root S=5.02 Tev
    (Springer, 2022) Tumasyan, A.; Karapınar, Güler
    The top quark pair production cross section is measured in proton-proton collisions at a center-of-mass energy of 5.02 TeV. The data were collected in a special LHC low-energy and low-intensity run in 2017, and correspond to an integrated luminosity of 302 pb(-1). The measurement is performed using events with one electron and one muon of opposite charge, and at least two jets. The measured cross section is 60.7 +/- 5.0 (stat) +/- 2.8 (syst) +/- 1.1 (lumi) pb. A combination with the result in the single lepton + jets channel, based on data collected in 2015 at the same center-of-mass energy and corresponding to an integrated luminosity of 27.4 pb(-1), is then performed. The resulting measured value is 63.0 +/- 4.1 (stat) +/- 3.0 (syst+lumi) pb, in agreement with the standard model prediction of 66.8(-3.1)(+2.9) pb.
  • Article
    Citation - WoS: 51
    Citation - Scopus: 28
    Search for Supersymmetry in Final States With Two or Three Soft Leptons and Missing Transverse Momentum in Proton-Proton Collisions at Root S=13 Tev
    (Springer, 2022) Karapınar, Güler; CMS Collaboration
    A search for supersymmetry in events with two or three low-momentum leptons and missing transverse momentum is performed. The search uses proton-proton collisions at root s = 13TeV collected in the three-year period 2016-2018 by the CMS experiment at the LHC and corresponding to an integrated luminosity of up to 137 fb(-1). The data are found to be in agreement with expectations from standard model processes. The results are interpreted in terms of electroweakino and top squark pair production with a small mass difference between the produced supersymmetric particles and the lightest neutralino. For the electroweakino interpretation, two simplified models are used, a wino-bino model and a higgsino model. Exclusion limits at 95% confidence level are set on (X) over tilde (0)(2) /(X) over tilde (+/-)(1) masses up to 275 GeV for a mass difference of 10 GeV in the wino-bino case, and up to 205(150) GeV for a mass difference of 7.5 (3) GeV in the higgsino case. The results for the higgsino are further interpreted using a phenomenological minimal supersymmetric standard model, excluding the higgsino mass parameter mu up to 180 GeV with the bino mass parameter M-1 at 800 GeV. In the top squark interpretation, exclusion limits are set at top squark masses up to 540 GeV for four-body top squark decays and up to 480 GeV for chargino-mediated decays with a mass difference of 30 GeV.
  • Article
    Citation - WoS: 26
    Citation - Scopus: 38
    Search for Long-Lived Particles Decaying Into Muon Pairs in Proton-Proton Collisions at Root S=13 Tev Collected With a Dedicated High-Rate Data Stream
    (Springer, 2022) Karapınar, Güler; CMS Collaboration
    A search for long-lived particles decaying into muon pairs is performed using proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment at the LHC in 2017 and 2018, corresponding to an integrated luminosity of 101 fb(-1). The data sets used in this search were collected with a dedicated dimuon trigger stream with low transverse momentum thresholds, recorded at high rate by retaining a reduced amount of information, in order to explore otherwise inaccessible phase space at low dimuon mass and nonzero displacement from the primary interaction vertex. No significant excess of events beyond the standard model expectation is found. Upper limits on branching fractions at 95% confidence level are set on a wide range of mass and lifetime hypotheses in beyond the standard model frameworks with the Higgs boson decaying into a pair of long-lived dark photons, or with a long-lived scalar resonance arising from a decay of a b hadron. The limits are the most stringent to date for substantial regions of the parameter space. These results can be also used to constrain models of displaced dimuons that are not explicitly considered in this paper.