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: 1Citation - Scopus: 9Search for Heavy Resonances Decaying To Z (ν Ν ¯)v (q Q ¯ ′) in Proton-Proton Collisions at S =13 Tev(American Physical Society, 2022) Karapınar, Güler; CMS CollaborationA search is presented for heavy bosons decaying to Z(νν¯)V(qq¯′), where V can be a W or a Z boson. A sample of proton-proton collision data at s=13 TeV was collected by the CMS experiment during 2016-2018. The data correspond to an integrated luminosity of 137 fb-1. The event categorization is based on the presence of high-momentum jets in the forward region to identify production through weak vector boson fusion. Additional categorization uses jet substructure techniques and the presence of large missing transverse momentum to identify W and Z bosons decaying to quarks and neutrinos, respectively. The dominant standard model backgrounds are estimated using data taken from control regions. The results are interpreted in terms of radion, W′ boson, and graviton models, under the assumption that these bosons are produced via gluon-gluon fusion, Drell-Yan, or weak vector boson fusion processes. No evidence is found for physics beyond the standard model. Upper limits are set at 95% confidence level on various types of hypothetical new bosons. Observed (expected) exclusion limits on the masses of these bosons range from 1.2 to 4.0 (1.1 to 3.7) TeV. © 2022 CERN.Article Citation - WoS: 25Citation - Scopus: 32Using Z Boson Events To Study Parton-Medium Interactions in Pb-Pb Collisions(American Physical Society, 2022) Karapınar, GülerThe spectra measurements of charged hadrons produced in the shower of a parton originating in the same hard scattering with a leptonically decaying Z boson arc reported in lead-lead nuclei (Pb-Pb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Both Pb-Pb and pp data sets are recorded by the CMS experiment at the LHC and correspond to an integrated luminosity of 1.7 nb(-1) and 320 pb(-1), respectively. Hadronic collision data with one reconstructed Z boson candidate with the transverse momentum p(T) > 30 GeV/c are analyzed. The Z boson constrains the initial energy and direction of the associated parton. In heavy ion events, azimuthal angular distributions of charged hadrons with respect to the direction of a Z boson are sensitive to modifications of the in-medium parton shower and medium response. compared to reference data from pp interactions, the results for central Pb-Pb collisions indicate a modification of the angular correlations. The measurements of the fragmentation functions and p(T) spectra of charged particles in Z boson events, which are sensitive to medium modifications of the parton shower longitudinal structure, are also reported. Significant modifications in central Pb-Pb events compared to the pp reference data are also found for these observables.Article Citation - WoS: 35Citation - Scopus: 41Search for Heavy Resonances Decaying To Ww, Wz, or Wh Boson Pairs in a Final State Consisting of a Lepton and a Large-Radius Jet in Proton-Proton Collisions at Root S=13 Tev(American Physical Society, 2022) Karapınar, GülerA search for new heavy resonances decaying to pairs of bosons (WW, WZ, or WH) is presented. The analysis uses data from proton-proton collisions collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb(-1). One of the bosons is required to be a W boson decaying to an electron or muon and a neutrino, while the other boson is required to be reconstructed as a single jet with mass and substructure compatible with a quark pair from a W, Z, or Higgs boson decay. The search is performed in the resonance mass range between 1.0 and 4.5 TeVand includes a specific search for resonances produced via vector boson fusion. The signal is extracted using a twodimensional maximum likelihood fit to the jet mass and the diboson invariant mass distributions. No significant excess is observed above the estimated background. Model-independent upper limits on the production cross sections of spin-0, spin-1, and spin-2 heavy resonances are derived as functions of the resonance mass and are interpreted in the context of bulk radion, heavy vector triplet, and bulk graviton models. The reported bounds are the most stringent to date.Article Citation - WoS: 27Citation - Scopus: 60Search for Bottom-Type, Vectorlike Quark Pair Production in a Fully Hadronic Final State in Proton-Proton Collisions at S =13 Tev(American Physical Society, 2020) Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Dremin,I.A search is described for the production of a pair of bottom-type vectorlike quarks (VLQs), each decaying into a b or b¯ quark and either a Higgs or a Z boson, with a mass greater than 1000 GeV. The analysis is based on data from proton-proton collisions at a 13 TeV center-of-mass energy recorded at the CERN LHC, corresponding to a total integrated luminosity of 137 fb-1. As the predominant decay modes of the Higgs and Z bosons are to a pair of quarks, the analysis focuses on final states consisting of jets resulting from the six quarks produced in the events. Since the two jets produced in the decay of a highly Lorentz-boosted Higgs or Z boson can merge to form a single jet, nine independent analyses are performed, categorized by the number of observed jets and the reconstructed event mode. No signal in excess of the expected background is observed. Lower limits are set on the VLQ mass at 95% confidence level equal to 1570 GeV in the case where the VLQ decays exclusively to a b quark and a Higgs boson, 1390 GeV for when it decays exclusively to a b quark and a Z boson, and 1450 GeV for when it decays equally in these two modes. These limits represent significant improvements over the previously published VLQ limits. © 2020 CERN.Article Citation - WoS: 6Citation - Scopus: 7Correlations of Azimuthal Anisotropy Fourier Harmonics With Subevent Cumulants in Ppb Collisions at Snn =8.16 Tev(American Physical Society, 2021) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Devetak, D.Event-by-event long-range correlations of azimuthal anisotropy Fourier coefficients (vn) in 8.16 TeV pPb data, collected by the CMS experiment at the CERN Large Hadron Collider, are extracted using a subevent four-particle cumulant technique applied to very low multiplicity events. Each combination of four charged particles is selected from either two, three, or four distinct subevent regions of a pseudorapidity range from -2.4 to 2.4 of the CMS tracker, and with transverse momentum between 0.3 and 3.0 GeV. Using the subevent cumulant technique, correlations between vn of different orders are measured as functions of particle multiplicity and compared to the standard cumulant method without subevents over a wide event multiplicity range. At high multiplicities, the v2 and v3 coefficients exhibit an anticorrelation; this behavior is observed consistently using various methods. The v2 and v4 correlation strength is found to depend on the number of subevents used in the calculation. As the event multiplicity decreases, the results from different subevent methods diverge because of different contributions of noncollective or few-particle correlations. Correlations extracted with the four-subevent method exhibit a tendency to diminish monotonically toward the lowest multiplicity region (about 20 charged tracks) investigated. These findings extend previous studies to a significantly lower event multiplicity range and establish the evidence for the onset of long-range collective multiparticle correlations in small system collisions. © 2021 CERN.Article Citation - WoS: 6Citation - Scopus: 9Studies of Inclusive Four-Jet Production With Two B-Tagged Jets in Proton-Proton Collisions at 7 Tev(American Physical Society, 2016) Karapınar, Güler; CMS CollaborationMeasurements are presented of the cross section for the production of at least four jets, of which at least two originate from b quarks, in proton-proton collisions. Data collected with the CMS detector at the LHC at a center-of-mass energy of 7 TeV are used, corresponding to an integrated luminosity of 3 pb(-1). The cross section is measured as a function of the jet transverse momentum for p(T) > 20 GeV, and of the jet pseudorapidity for |eta| < 2.4 (b jets), 4.7 (untagged jets). The correlations in azimuthal angle and pT between the jets are also studied. The inclusive cross section is measured to be sigma(pp -> 2b + 2j + X) = 69 +/- 3(stat) +/- 24(syst) nb. The eta and p(T) distributions of the four jets and the correlations between them are well reproduced by event generators that combine perturbative QCD calculations at next-to-leading-order accuracy with contributions from parton showers and multiparton interactions.Article Citation - WoS: 22Citation - Scopus: 22Searches for R-Parity Supersymmetry in Pp Collisions at Root S=8 Tev in Final States With 0-4 Leptons(American Physical Society, 2016) Karapınar, Güler; CMS CollaborationResults are presented from searches for R-parity-violating supersymmetry in events produced in pp collisions at root s = 8 TeV at the LHC. Final states with 0, 1, 2, or multiple leptons are considered independently. The analysis is performed on data collected by the CMS experiment corresponding to an integrated luminosity of 19.5 fb(-1). No excesses of events above the standard model expectations are observed, and 95% confidence level limits are set on supersymmetric particle masses and production cross sections. The results are interpreted in models featuring R-parity-violating decays of the lightest supersymmetric particle, which in the studied scenarios can be either the gluino, a bottom squark, or a neutralino. In a gluino pair production model with baryon number violation, gluinos with a mass less than 0.98 and 1.03 TeV are excluded, by analyses in a fully hadronic and one-lepton final state, respectively. An analysis in a dilepton final state is used to exclude bottom squarks with masses less than 307 GeV in a model considering bottom squark pair production. Multilepton final states are considered in the context of either strong or electroweak production of superpartners and are used to set limits on the masses of the lightest supersymmetric particles. These limits range from 300 to 900 GeV in models with leptonic and up to approximately 700 GeV in models with semileptonic R-parity-violating couplings.Article Citation - WoS: 107Citation - Scopus: 124Search for Supersymmetry in Multijet Events With Missing Transverse Momentum in Proton-Proton Collisions at 13 Tev(American Physical Society, 2017) Karapınar, GülerA search for supersymmetry is presented based on multijet events with large missing transverse momentum produced in proton-proton collisions at a center-of-mass energy of root s = 13 TeV. The data, corresponding to an integrated luminosity of 35.9 fb(-1), were collected with the CMS detector at the CERN LHC in 2016. The analysis utilizes four-dimensional exclusive search regions defined in terms of the number of jets, the number of tagged bottom quark jets, the scalar sum of jet transverse momenta, and the magnitude of the vector sum of jet transverse momenta. No evidence for a significant excess of events is observed relative to the expectation from the standard model. Limits on the cross sections for the pair production of gluinos and squarks are derived in the context of simplified models. Assuming the lightest supersymmetric particle to be a weakly interacting neutralino, 95% confidence level lower limits on the gluino mass as large as 1800 to 1960 GeV are derived, and on the squark mass as large as 960 to 1390 GeV, depending on the production and decay scenario.Article Citation - WoS: 56Citation - Scopus: 66Measurement of Charged Pion, Kaon, and Proton Production in Proton-Proton Collisions at Root S=13 Tev(American Physical Society, 2017) Karapınar, Güler; CMS CollaborationTransverse momentum spectra of charged pions, kaons, and protons are measured in proton-proton collisions at root s = 13 TeV with the CMS detector at the LHC. The particles, identified via their energy loss in the silicon tracker, are measured in the transverse momentum range of p(T) approximate to 0.1-1.7 GeV/c and rapidities vertical bar y vertical bar < 1. The pT spectra and integrated yields are compared to previous results at smaller ffiffiffi root s and to predictions of Monte Carlo event generators. The average pT increases with particle mass and charged particle multiplicity of the event. Comparisons with previous CMS results at root s = 0.9, 2.76, and 7 TeV show that the average pT and the ratios of hadron yields feature very similar dependences on the particle multiplicity in the event, independently of the center-of-mass energy of the pp collision.Article Citation - WoS: 13Citation - Scopus: 28Measurement of the Top Quark Mass in the Dileptonic T(t)over-Bar Decay Channel Using the Mass Observables M-Bl, M-T2, and M-Blv in Pp Collisions at Root=8 Tev(American Physical Society, 2017) Karapınar, Güler; CMS CollaborationA measurement of the top quark mass (M-t) in the dileptonic t (t) over bar decay channel is performed using data from proton-proton collisions at a center-of-mass energy of 8 TeV. The data was recorded by the CMS experiment at the LHC and corresponds to an integrated luminosity of 19.7 +/- 0.5 fb(-1). Events are selected with two oppositely charged leptons (l = e, mu) and two jets identified as originating from b quarks. The analysis is based on three kinematic observables whose distributions are sensitive to the value of Mt. An invariant mass observable, M-bl, and a "stransverse mass" observable, M-T2, are employed in a simultaneous fit to determine the value of M-t and an overall jet energy scale factor (JSF). A complementary approach is used to construct an invariant mass observable, M-blv, that is combined with M-T2 to measure M-t. The shapes of the observables, along with their evolutions in M-t and JSF, are modeled by a nonparametric Gaussian process regression technique. The sensitivity of the observables to the value of M-t is investigated using a Fisher information density method. The top quark mass is measured to be 172.22 +/- 0.18(stat)(-0.93)(+0.89) (syst) GeV.