Rectorate / Rektörlük
Permanent URI for this collectionhttps://hdl.handle.net/11147/6849
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Article Citation - WoS: 21Citation - Scopus: 28Angular Analysis of the Decay B+-> K*(892)(+)mu(+)mu(-) in Proton-Proton Collisions at Root S=8 Tev(Springer, 2021) CMS Collaboration; Karapınar, GülerAngular distributions of the decay B+-> K*(892)(+)mu(+)mu(-) are studied using events collected with the CMS detector in root s = 8 TeV proton-proton collisions at the LHC, corresponding to an integrated luminosity of 20.0 fb(-1). The forward-backward asymmetry of the muons and the longitudinal polarization of the K*(892)(+) meson are determined as a function of the square of the dimuon invariant mass. These are the first results from this exclusive decay mode and are in agreement with a standard model prediction.Article Citation - WoS: 16Citation - Scopus: 16Dependence of Inclusive Jet Production on the Anti-K(t) Distance Parameter in Pp Collisions at Root S=13 Tev(Springer, 2020) CMS Collaboration; Karapınar, GülerThe dependence of inclusive jet production in proton-proton collisions with a center-of-mass energy of 13 TeV on the distance parameter R of the anti-k(T) algorithm is studied using data corresponding to integrated luminosities up to 35.9 fb(-1) collected by the CMS experiment in 2016. The ratios of the inclusive cross sections as functions of transverse momentum p(T) and rapidity y, for R in the range 0.1 to 1.2 to those using R = 0.4 are presented in the region 84 < p(T)< 1588 GeV and |y|< 2.0. The results are compared to calculations at leading and next-to-leading order in the strong coupling constant using different parton shower models. The variation of the ratio of cross sections with R is well described by calculations including a parton shower model, but not by a leading-order quantum chromodynamics calculation including nonperturbative effects. The agreement between the data and the theoretical predictions for the ratios of cross sections is significantly improved when next-to-leading order calculations with nonperturbative effects are used.Article Citation - WoS: 5Citation - Scopus: 9Measurements of the Differential Cross Sections of the Production of Z Plus Jets and Gamma Plus Jets and of Z Boson Emission Collinear With a Jet in Pp Collisions at Root S=13 Tev(Springer, 2021) CMS Collaboration; Karapınar, GülerMeasurements of the differential cross sections of Z + jets and gamma + jets production, and their ratio, are presented as a function of the boson transverse momentum. Measurements are also presented of the angular distribution between the Z boson and the closest jet. The analysis is based on pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb(-1) recorded by the CMS experiment at the LHC. The results, corrected for detector effects, are compared with various theoretical predictions. In general, the predictions at higher orders in perturbation theory show better agreement with the measurements. This work provides the first measurement of the ratio of the differential cross sections of Z + jets and gamma + jets production at 13 TeV, as well as the first direct measurement of Z bosons emitted collinearly with a jet.Article Citation - WoS: 13Citation - Scopus: 26Search for Chargino-Neutralino Production in Events With Higgs and W Bosons Using 137 Fb(-1) of Proton-Proton Collisions at Root S=13 Tev(Springer, 2021) Karapınar, Güler; CMS CollaborationA search for electroweak production of supersymmetric (SUSY) particles in final states with one lepton, a Higgs boson decaying to a pair of bottom quarks, and large missing transverse momentum is presented. The search uses data from proton-proton collisions at a center-of-mass energy of 13 TeV collected using the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb(-1). The observed yields are consistent with backgrounds expected from the standard model. The results are interpreted in the context of a simplified SUSY model of chargino-neutralino production, with the chargino decaying to a W boson and the lightest SUSY particle (LSP) and the neutralino decaying to a Higgs boson and the LSP. Charginos and neutralinos with masses up to 820 GeV are excluded at 95% confidence level when the LSP mass is small, and LSPs with mass up to 350 GeV are excluded when the masses of the chargino and neutralino are approximately 700 GeV.Article Citation - WoS: 129Citation - Scopus: 221Search for Resonant and Nonresonant New Phenomena in High-Mass Dilepton Final States at Root S=13 Tev(Springer, 2021) Karapınar, Güler; CMS CollaborationA search is presented for physics beyond the standard model (SM) using electron or muon pairs with high invariant mass. A data set of proton-proton collisions collected by the CMS experiment at the LHC at root s = 13 TeV from 2016 to 2018 corresponding to a total integrated luminosity of up to 140 fb(-1) is analyzed. No significant deviation is observed with respect to the SM background expectations. Upper limits are presented on the ratio of the product of the production cross section and the branching fraction to dileptons of a new narrow resonance to that of the Z boson. These provide the most stringent lower limits to date on the masses for various spin-1 particles, spin-2 gravitons in the Randall-Sundrum model, as well as spin-1 mediators between the SM and dark matter particles. Lower limits on the ultraviolet cutoff parameter are set both for four-fermion contact interactions and for the Arkani-Hamed, Dimopoulos, and Dvali model with large extra dimensions. Lepton flavor universality is tested at the TeV scale for the first time by comparing the dimuon and dielectron mass spectra. No significant deviation from the SM expectation of unity is observed.Article Citation - WoS: 6Citation - Scopus: 6Measurement of B Jet Shapes in Proton-Proton Collisions at Root S=5.02 Tev(Springer, 2021) CMS Collaboration; Karapınar, GülerWe present the first study of charged-hadron production associated with jets originating from b quarks in proton-proton collisions at a center-of-mass energy of 5.02 TeV. The data sample used in this study was collected with the CMS detector at the CERN LHC and corresponds to an integrated luminosity of 27.4 pb(-1). To characterize the jet substructure, the differential jet shapes, defined as the normalized transverse momentum distribution of charged hadrons as a function of angular distance from the jet axis, are measured for b jets. In addition to the jet shapes, the per-jet yields of charged particles associated with b jets are also quantified, again as a function of the angular distance with respect to the jet axis. Extracted jet shape and particle yield distributions for b jets are compared with results for inclusive jets, as well as with the predictions from the pythia and herwig++ event generators.Article Citation - WoS: 8Citation - Scopus: 49Measurement of the Inclusive and Differential Higgs Boson Production Cross Sections in the Leptonic Ww Decay Mode at P Root S=13 Tev(Springer, 2021) CMS Collaboration; Karapınar, GülerMeasurements of the fiducial inclusive and differential production cross sections of the Higgs boson in proton-proton collisions at root s = 13 TeV are performed using events where the Higgs boson decays into a pair of W bosons that subsequently decay into a final state with an electron, a muon, and a pair of neutrinos. The analysis is based on data collected with the CMS detector at the LHC during 2016-2018, corresponding to an integrated luminosity of 137 fb(-1). Production cross sections are measured as a function of the transverse momentum of the Higgs boson and the associated jet multiplicity. The Higgs boson signal is extracted and simultaneously unfolded to correct for selection efficiency and resolution effects using maximum-likelihood fits to the observed distributions in data. The integrated fiducial cross section is measured to be 86.5 +/- 9.5 fb, consistent with the Standard Model expectation of 82.5 +/- 4.2 fb. No significant deviation from the Standard Model expectations is observed in the differential measurements.Article Citation - WoS: 44Citation - Scopus: 78Search for Nonresonant Higgs Boson Pair Production in Final States With Two Bottom Quarks and Two Photons in Proton-Proton Collisions at Root S=13 Tev(Springer, 2021) CMS Collaboration; Karapınar, GülerA search for nonresonant production of Higgs boson pairs via gluon-gluon and vector boson fusion processes in final states with two bottom quarks and two photons is presented. The search uses data from proton-proton collisions at a center-of-mass energy of root s = 13 TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb(-1). No significant deviation from the background-only hypothesis is observed. An upper limit at 95% confidence level is set on the product of the Higgs boson pair production cross section and branching fraction into gamma gamma b (b) over bar. The observed (expected) upper limit is determined to be 0.67 (0.45) fb, which corresponds to 7.7 (5.2) times the standard model prediction. This search has the highest sensitivity to Higgs boson pair production to date. Assuming all other Higgs boson couplings are equal to their values in the standard model, the observed coupling modifiers of the trilinear Higgs boson self-coupling kappa(lambda) and the coupling between a pair of Higgs bosons and a pair of vector bosons c(2V) are constrained within the ranges -3.3 < kappa(lambda) < 8.5 and -1.3 < c(2V) < 3.5 at 95% confidence level. Constraints on kappa(lambda) are also set by combining this analysis with a search for single Higgs bosons decaying to two photons, produced in association with top quark-antiquark pairs, and by performing a simultaneous fit of kappa(lambda) and the top quark Yukawa coupling modifier kappa(t).Article Citation - WoS: 2Citation - Scopus: 9Measurement of the Z Boson Differential Production Cross Section Using Its Invisible Decay Mode (z -> Nu(nu)over-Bar) in Proton-Proton Collisions at Root S=13 Tev(Springer, 2021) Karapınar, Güler; CMS CollaborationMeasurements of the total and differential fiducial cross sections for the Z boson decaying into two neutrinos are presented at the LHC in proton-proton collisions at a center-of-mass energy of 13TeV. The data were collected by the CMS detector in 2016 and correspond to an integrated luminosity of 35.9 fb(-1). In these measurements, events are selected containing an imbalance in transverse momentum and one or more energetic jets. The fiducial differential cross section is measured as a function of the Z boson transverse momentum. The results are combined with a previous measurement of charged-lepton decays of the Z boson. The measured total fiducial cross section for events with Z boson transverse momentum greater than 200 GeV is 3000(-170)(+180) fb.Article Citation - WoS: 8Citation - Scopus: 11Measurement of Differential Cross Sections for Z Bosons Produced in Association With Charm Jets in Pp Collisions at Root S=13 Tev(Springer, 2021) Karapınar, Güler; CMS CollaborationMeasurements are presented of differential cross sections for the production of Z bosons in association with at least one jet initiated by a charm quark in pp collisions at root s = 13 TeV. The data recorded by the CMS experiment at the LHC correspond to an integrated luminosity of 35.9 fb(-1). The final states contain a pair of electrons or muons that are the decay products of a Z boson, and a jet consistent with being initiated by a charm quark produced in the hard interaction. Differential cross sections as a function of the transverse momentum p(T) of the Z boson and p(T) of the charm jet are compared with predictions from Monte Carlo event generators. The inclusive production cross section 405.4 +/- 5.6 (stat) +/- 24.3 (exp) +/- 3.7 (theo) pb, is measured in a fiducial region requiring both leptons to have pseudorapidity |eta| < 2.4 and p(T)> 10 GeV, at least one lepton with p(T)> 26 GeV, and a mass of the pair in the range 71-111 GeV, while the charm jet is required to have p(T)> 30 GeV and |eta| < 2.4. These are the first measurements of these cross sections in proton-proton collisions at 13 TeV.