WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 1Citation - Scopus: 2First Measurement of the Forward Rapidity Gap Distribution in Ppb Collisions at √snn=8.16 Tev(Amer Physical Soc, 2023) Karapınar, Güler; CMS Collaboration; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; Ero, J.; Zhokin, A.For the first time at LHC energies, the forward rapidity gap spectra from proton-lead collisions for both proton and lead dissociation processes are presented. The analysis is performed over 10.4 units of pseudorapidity at a center-of-mass energy per nucleon pair of ffisffi than in previous measurements of diffractive production in proton-nucleus collisions. For lead dissociation processes, which correspond to the pomeron-lead event topology, the EPOS-LHC generator predictions are a factor of 2 below the data, but the model gives a reasonable description of the rapidity gap spectrum shape. For the pomeron-proton topology, the EPOS-LHC, QGSJET II, and HIJING predictions are all at least a factor of 5 lower than the data. The latter effect might be explained by a significant contribution of ultraperipheral photoproduction events mimicking the signature of diffractive processes. These data may be of significant help in understanding the high energy limit of quantum chromodynamics and for modeling cosmic ray air showers.Article Citation - WoS: 13Evidence for Ww/Wz Vector Boson Scattering in the Decay Channel <i>l</I>νqq Produced in Association With Two Jets in Proton-Proton Collisions at √<i>s</I>=13tev(Elsevier, 2022) Karapınar, Güler; CMS Collaboration; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Vetens, W.Evidence is reported for electroweak (EW) vector boson scattering in the decay channel l nu qq of two weak vector bosons WV(V = Wor Z), produced in association with two parton jets. The search uses a data set of proton-proton collisions at 13TeVcollected with the CMS detector during 2016-2018 with an integrated luminosity of 138fb(-1). Events are selected requiring one lepton (electron or muon), moderate missing transverse momentum, two jets with a large pseudorapidity separation and a large dijet invariant mass, and a signature consistent with the hadronic decay of a W/Zboson. The cross section is computed in a fiducial phase space defined at parton level requiring all parton transverse momenta p(T)> 10 GeVand at least one pair of outgoing partons with invariant mass mqq> 100 GeV. The measured and expected EW WVproduction cross sections are 1.90(-0.46)(+0.5)3 pb and 2.23(-0.11)(+0.08)(scale) +/- 0.05(PDF) pb, respectively, where PDF is the parton distribution function. The observed EW signal strength is mu EW= 0.85 +/- 0.12 (stat)(-0.17)(+0.19)(syst), corresponding to a signal significance of 4.4 standard deviations with 5.1 expected, and it is measured keeping the quantum chromodynamics (QCD) associated diboson production fixed to the standard model prediction. This is the first evidence of vector boson scattering in the l nu qq decay channel at LHC. The simultaneous measurement of the EW and QCD associated diboson production agrees with the standard model prediction. (C) 2022 The Author(s). Published by Elsevier B.V.Article Citation - WoS: 20Nuclear Modification of Y States in Ppb Collisions at Root S-Nn=5.02 Tev(Elsevier, 2022) Tumasyan, A.; Karapınar, GülerProduction cross sections of Y(1S), Y(2S), and Y(3S) states decaying into mu(+)mu(-) in proton-lead (pPb) collisions are reported using data collected by the CMS experiment at root S-NN= 5.02 TeV. A comparison is made with corresponding cross sections obtained with ppdata measured at the same collision energy and scaled by the Pb nucleus mass number. The nuclear modification factor for Y(1S) is found to be R-pPb(Y(1S)) = 0.806 +/- 0.024 (stat)+/- 0.059 (syst). Similar results for the excited states indicate a sequential suppression pattern, such that R-pPb(Y(1S)) > R-pPb(Y(2S)) > R-pPb(Y(3S)). The suppression of all states is much less pronounced in pPbthan in PbPbcollisions, and independent of transverse momentum p(T)(Y) and center-of-mass rapidity y(CM)(Y) of the individual Y state in the studied range p(T)(Y) < 30GeV/c and |y(CM)(Y)| < 1.93. Models that incorporate final-state effects of bottomonia in pPb collisions are in better agreement with the data than those which only assume initial-state modifications. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).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.Erratum Citation - WoS: 3Citation - Scopus: 7Searches 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]Article Citation - WoS: 9Citation - Scopus: 13Probing Charm Quark Dynamics Via Multiparticle Correlations in Pb-Pb Collisions at Root S(nn)=5.02 Tev(Amer Physical Soc, 2022) Tumasyan, A.; Karapınar, GülerMultiparticle azimuthal correlations of prompt D-0 mesons arc measured in Pb-Pb collisions at a nucleon-nucleon center-of-mass energy of root s(NN) = 5.02 TeV. For the first time, a four-particle cumulant method is used to extract the second Fourier coefficient of the azimuthal distribution (v(2)) of D-0 mesons as a function of event centrality and the D-0 transverse momentum. The ratios of the four-particle v(2) values to previously measured two-particle cumulant results provide direct experimental access to event-by-event fluctuations of charm quark azimuthal anisotropies. These ratios are also found to be comparable to those of inclusive charged particles in the event. However, hints of deviations are seen in the most central and peripheral collisions. To investigate the origin of flow fluctuations in the charm sector, these measurements are compared to a model implementing fluctuations of charm quark energy loss via collisional or radiative processes in the quark-gluon plasma. These models cannot quantitatively describe the data over the full transverse momentum and centrality ranges, although the calculations with collisional energy loss provide a better description of the data.Article Citation - WoS: 5Citation - Scopus: 9Search for Resonances Decaying To Three W Bosons in Proton-Proton Collisions at Root S=13 Tev(American Physical Society, 2022) Karapınar, Güler; CMS CollaborationA search for resonances decaying into a W boson and a radion, where the radion decays into two W bosons, is presented. The data analyzed correspond to an integrated luminosity of 138 fb???1 recorded in ffiffiproton-proton collisions with the CMS detector at p s 1/4 13 TeV. One isolated charged lepton is required, together with missing transverse momentum and one or two massive large-radius jets, containing the decay products of either two or one W bosons, respectively. No excess over the background estimation is observed. The results are combined with those from a complementary channel with an all-hadronic final state, described in an accompanying paper. Limits are set on parameters of an extended warped extradimensional model. These searches are the first of their kind at the LHC.Article Citation - WoS: 26First Search for Exclusive Diphoton Production at High Mass With Tagged Protons in Proton-Proton Collisions at Root S=13 Tev(Amer Physical Soc, 2022) Tumasyan, A.; Karapınar, GülerA search for exclusive two-photon production via photon exchange in proton-proton collisions, pp -> p gamma gamma p with intact protons, is presented. The data correspond to an integrated luminosity of 9.4 fb(-1) collected in 2016 using the CMS and TOTEM detectors at a center-of-mass energy of 13 TeVat the LHC. Events are selected with a diphoton invariant mass above 350 GeVand with both protons intact in the final state, to reduce backgrounds from strong interactions. The events of interest are those where the invariant mass and rapidity calculated from the momentum losses of the forward-moving protons match the mass and rapidity of the central, two-photon system. No events are found that satisfy this condition. Interpreting this result in an effective dimension-8 extension of the standard model, the first limits are set on the two anomalous four-photon coupling parameters. If the other parameter is constrained to its standard model value, the limits at 95% confidence level are vertical bar zeta(1)vertical bar < 2.9 x 10(-1)3 GeV-4 and vertical bar zeta(2)vertical bar < 6.0 x 10(-13) GeV-4.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: 6Citation - Scopus: 27Measurement of the Inclusive and Differential Higgs Boson Production Cross Sections in the Decay Mode To a Pair of Tau Leptons in Pp Collisions at Root S=13 Tev(Amer Physical Soc, 2022) Tumasyan, A.; Karapınar, GülerMeasurements of the inclusive and differential fiducial cross sections of the Higgs boson are presented, using the tau lepton decay channel. The differential cross sections are measured as functions of the Higgs boson transverse momentum, jet multiplicity, and transverse momentum of the leading jet in the event, if any. The analysis is performed using proton-proton collision data collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 138 fb-1. These are the first differential measurements of the Higgs boson cross section in the final state of two tau leptons. In final states with a large jet multiplicity or with a Lorentz-boosted Higgs boson, these measurements constitute a significant improvement over measurements performed in other final states.