Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Access type: Open accessSubject: search.filters.subject.Hadron-Hadron Scattering

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  • Erratum
    Citation - WoS: 13
    Citation - Scopus: 9
    Erratum: Measurement of the Tt̄ Production Cross Section in the Dilepton Channel in pp Collisions at √s = 8 TeV (Journal of High Energy Physics (2014) 02 (024))
    (Springer Verlag, 2014) Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Smith, W. H.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 14
    Combination of Inclusive Top-Quark Pair Production Cross-Section Measurements Using Atlas and Cms Data at S = 7 and 8 Tev
    (Springer Science and Business Media Deutschland GmbH, 2023) Aad,G.; Abbott,B.; Abbott,D.C.; Abed Abud,A.; Abeling,K.; Abhayasinghe,D.K.; Jiggins,S.
    A combination of measurements of the inclusive top-quark pair production cross-section performed by ATLAS and CMS in proton–proton collisions at centre-of-mass energies of 7 and 8 TeV at the LHC is presented. The cross-sections are obtained using top-quark pair decays with an opposite-charge electron–muon pair in the final state and with data corresponding to an integrated luminosity of about 5 fb−1 at s = 7 TeV and about 20 fb−1 at s = 8 TeV for each experiment. The combined cross-sections are determined to be 178.5 ± 4.7 pb at s = 7 TeV and 243.3−5.9+6.0 pb at s = 8 TeV with a correlation of 0.41, using a reference top-quark mass value of 172.5 GeV. The ratio of the combined cross-sections is determined to be R8/7 = 1.363 ± 0.032. The combined measured cross-sections and their ratio agree well with theory calculations using several parton distribution function (PDF) sets. The values of the top-quark pole mass (with the strong coupling fixed at 0.118) and the strong coupling (with the top-quark pole mass fixed at 172.5 GeV) are extracted from the combined results by fitting a next-to-next-to-leading-order plus next-to-next-to-leading-log QCD prediction to the measurements. Using a version of the NNPDF3.1 PDF set containing no top-quark measurements, the results obtained are mtpole=173.4−2.0+1.8 GeV and αsmZ=0.1170−0.0018+0.0021. © The Author(s) 2023.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 3
    Search for Cp Violating Top Quark Couplings in Pp Collisions at √s = 13 Tev
    (Springer Science and Business Media Deutschland GmbH, 2023) Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Escalante, Del, Valle, A.; Frühwirth, R.; Jeitler, M.
    Results are presented from a search for CP violation in top quark pair production, using proton-proton collisions at a center-of-mass energy of 13 TeV. The data used for this analysis consist of final states with two charged leptons collected by the CMS experiment, and correspond to an integrated luminosity of 35.9 fb−1. The search uses two observables, O1 and O3, which are Lorentz scalars. The observable O1 is constructed from the four-momenta of the charged leptons and the reconstructed top quarks, while O3 consists of the four-momenta of the charged leptons and the b quarks originating from the top quarks. Asymmetries in these observables are sensitive to CP violation, and their measurement is used to determine the chromoelectric dipole moment of the top quark. The results are consistent with the expectation from the standard model. [Figure not available: see fulltext.]. © 2023, The Author(s).
  • 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: 39
    Citation - Scopus: 48
    Analysis of the Cp Structure of the Yukawa Coupling Between the Higgs Boson and Tau Leptons in Proton-Proton Collisions at Root S=13 Tev
    (Springer, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Del Valle, A. Escalante
    The first measurement of the CP structure of the Yukawa coupling between the Higgs boson and tau leptons is presented. The measurement is based on data collected in proton-proton collisions at root s = 13 TeV by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb(-1). The analysis uses the angular correlation between the decay planes of tau leptons produced in Higgs boson decays. The effective mixing angle between CP-even and CP-odd tau Yukawa couplings is found to be -1 +/- 19 degrees, compared to an expected value of 0 +/- 21 degrees at the 68.3% confidence level. The data disfavour the pure CP-odd scenario at 3.0 standard deviations. The results are compatible with predictions for the standard model Higgs boson.
  • 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.