Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 8Citation - Scopus: 17Measurement of the Associated Production of a Z Boson With Charm or Bottom Quark Jets in Proton-Proton Collisions at S =13 Tev(American Physical Society, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Tyurin, N.; 01. Izmir Institute of TechnologyRatios of cross sections, σ(Z+c jets)/σ(Z+jets), σ(Z+b jets)/σ(Z+jets), and σ(Z+c jets)/σ(Z+b jets) in the associated production of a Z boson with at least one charm or bottom quark jet are measured in proton-proton collisions at s=13 TeV. The data sample, collected by the CMS experiment at the CERN LHC, corresponds to an integrated luminosity of 35.9 fb-1, with a fiducial volume of pT>30 GeV and |η|<2.4 for the jets, where pT and η represent transverse momentum and pseudorapidity, respectively. The Z boson candidates come from leptonic decays into electrons or muons with pT>25 GeV and |η|<2.4, and the dilepton mass satisfies 71<mZ<111 GeV. The measured values are σ(Z+c jets)/σ(Z+jets)=0.102±0.002±0.009, σ(Z+b jets)/σ(Z+jets)=0.0633±0.0004±0.0015, and σ(Z+c jets)/σ(Z+b jets)=1.62±0.03±0.15. Results on the inclusive and differential cross section ratios as functions of jet and Z boson transverse momentum are compared with predictions from leading and next-to-leading order perturbative quantum chromodynamics calculations. These are the first measurements of the cross section ratios at 13 TeV. © 2020 American Physical Society. All rights reserved.Article Citation - WoS: 14Citation - Scopus: 30Search for the Production of W±w±w Events at S =13 Tev(American Physical Society, 2019) Sirunyan, A.M.; Karapınar, Güler; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Azhgirey, I.; 01. Izmir Institute of TechnologyA search for the production of events containing three W bosons predicted by the standard model is reported. The search is based on a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the CMS experiment at the CERN LHC and corresponding to a total integrated luminosity of 35.9 fb-1. The search is performed in final states with three leptons (electrons or muons), or with two same-charge leptons plus two jets. The observed (expected) significance of the signal for W±W±W production is 0.60 (1.78) standard deviations, and the ratio of the measured signal yield to that expected from the standard model is 0.34-0.34+0.62. Limits are placed on three anomalous quartic gauge couplings and on the production of massive axionlike particles. © 2019 CERN.Article Citation - WoS: 57Citation - Scopus: 90Search for Vectorlike Leptons in Multilepton Final States in Proton-Proton Collisions at S =13 Tev(American Physical Society, 2019) Sirunyan, A.M.; Karapınar, Güler; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Bitioukov, S.; 01. Izmir Institute of TechnologyA search for vectorlike leptons in multilepton final states is presented. The data sample corresponds to an integrated luminosity of 77.4 fb-1 of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC in 2016 and 2017. Events are categorized by the multiplicity of electrons, muons, and hadronically decaying τ leptons. The missing transverse momentum and the scalar sum of the lepton transverse momenta are used to distinguish the signal from background. The observed results are consistent with the expectations from the standard model hypothesis. The existence of a vectorlike lepton doublet, coupling to the third-generation standard model leptons in the mass range of 120-790 GeV, is excluded at 95% confidence level. These are the most stringent limits yet on the production of a vectorlike lepton doublet, coupling to the third-generation standard model leptons. © 2019 CERN, for the CMS Collaboration.Article Citation - WoS: 12Citation - Scopus: 20Measurement of the Top Quark Yukawa Coupling From T T Kinematic Distributions in the Lepton+jets Final State in Proton-Proton Collisions at S =13 Tev Measurement of the Top Quark Yukawa Coupling From ... Sirunyan Et Al.(American Physical Society, 2019) Sirunyan, A.M.; Karapınar, Güler; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Bitioukov, S.; 01. Izmir Institute of TechnologyResults are presented for an extraction of the top quark Yukawa coupling from top quark-antiquark (tt) kinematic distributions in the lepton plus jets final state in proton-proton collisions, based on data collected by the CMS experiment at the LHC at s=13 TeV, corresponding to an integrated luminosity of 35.8 fb-1. Corrections from weak boson exchange, including Higgs bosons, between the top quarks can produce large distortions of differential distributions near the energy threshold of tt production. Therefore, precise measurements of these distributions are sensitive to the Yukawa coupling. Top quark events are reconstructed with at least three jets in the final state, and a novel technique is introduced to reconstruct the tt system for events with one missing jet. This technique enhances the experimental sensitivity in the low invariant mass region, Mtt. The data yields in Mtt, the rapidity difference |yt-yt|, and the number of reconstructed jets are compared with distributions representing different Yukawa couplings. These comparisons are used to measure the ratio of the top quark Yukawa coupling to its standard model predicted value to be 1.07-0.43+0.34 with an upper limit of 1.67 at the 95% confidence level. © 2019 CERN.Article Citation - WoS: 9Citation - Scopus: 37Search for a Light Charged Higgs Boson Decaying To a W Boson and a Cp -Odd Higgs Boson in Final States With Eμμ or Μμμ in Proton-Proton Collisions at S =13 Tev(American Physical Society, 2019) Sirunyan, A.M.; Karapınar, Güler; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Savrin, V.; 01. Izmir Institute of TechnologyA search for a light charged Higgs boson (H+) decaying to a W boson and a CP-odd Higgs boson (A) in final states with eμμ or μμμ is performed using data from pp collisions at s=13 TeV, recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 35.9 fb-1. In this search, it is assumed that the H+ boson is produced in decays of top quarks, and the A boson decays to two oppositely charged muons. The presence of signals for H+ boson masses between 100 and 160 GeV and A boson masses between 15 and 75 GeV is investigated. No evidence for the production of the H+ boson is found. Upper limits at 95% confidence level are obtained on the combined branching fraction for the decay chain, t→bH+→bW+A→bW+μ+μ-, of 1.9×10-6 to 8.6×10-6, depending on the masses of the H+ and A bosons. These are the first limits for these decay modes of the H+ and A bosons. © 2019 CERN.Article Citation - WoS: 20Citation - Scopus: 48Search for Low-Mass Quark-Antiquark Resonances Produced in Association With a Photon at S =13 Tev(American Physical Society, 2019) Sirunyan, A.M.; Karapınar, Güler; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Obraztsov, S.; 01. Izmir Institute of TechnologyA search for narrow low-mass resonances decaying to quark-antiquark pairs is presented. The search is based on proton-proton collision events collected at 13 TeV by the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 35.9 fb-1, recorded in 2016. The search considers the case where the resonance has high transverse momentum due to initial-state radiation of a hard photon. To study this process, the decay products of the resonance are reconstructed as a single large-radius jet with two-pronged substructure. The signal would be identified as a localized excess in the jet invariant mass spectrum. No evidence for such a resonance is observed in the mass range 10 to 125 GeV. Upper limits at the 95% confidence level are set on the coupling strength of resonances decaying to quark pairs. The results obtained with this photon trigger strategy provide the first direct constraints on quark-antiquark resonance masses below 50 GeV obtained at a hadron collider. © 2019 CERN. for the CMS Collaboration. Published by the American Physical Society under the terms of the https://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Article Citation - WoS: 28Citation - Scopus: 46Search for Long-Lived Particles Using Delayed Photons in Proton-Proton Collisions at S =13 Tev(American Physical Society, 2019) Sirunyan, A.M.; Karapınar, Güler; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Babaev, A.; 01. Izmir Institute of TechnologyA search for long-lived particles decaying to photons and weakly interacting particles, using proton-proton collision data at s=13 TeV collected by the CMS experiment in 2016-2017 is presented. The data set corresponds to an integrated luminosity of 77.4 fb-1. Results are interpreted in the context of supersymmetry with gauge-mediated supersymmetry breaking, where the neutralino is long-lived and decays to a photon and a gravitino. Limits are presented as a function of the neutralino proper decay length and mass. For neutralino proper decay lengths of 0.1, 1, 10, and 100 m, masses up to 320, 525, 360, and 215 GeV are excluded at 95% confidence level, respectively. We extend the previous best limits in the neutralino proper decay length by up to one order of magnitude, and in the neutralino mass by up to 100 GeV. © 2019 CERN, for the CMS Collaboration. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/" Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Article Citation - WoS: 1Citation - Scopus: 1Search for Physics Beyond the Standard Model in Events With Overlapping Photons and Jets(American Physical Society, 2019) Sirunyan, A.M.; Karapınar, Güler; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Azhgirey, I.; 01. Izmir Institute of TechnologyResults are reported from a search for new particles that decay into a photon and two gluons, in events with jets. Novel jet substructure techniques are developed that allow photons to be identified in an environment densely populated with hadrons. The analyzed proton-proton collision data were collected by the CMS experiment at the LHC, in 2016 at s=13 TeV, and correspond to an integrated luminosity of 35.9 fb-1. The spectra of total transverse hadronic energy of candidate events are examined for deviations from the standard model predictions. No statistically significant excess is observed over the expected background. The first cross section limits on new physics processes resulting in such events are set. The results are interpreted as upper limits on the rate of gluino pair production, utilizing a simplified stealth supersymmetry model. The excluded gluino masses extend up to 1.7 TeV, for a neutralino mass of 200 GeV and exceed previous mass constraints set by analyses targeting events with isolated photons. .