Rectorate / Rektörlük
Permanent URI for this collectionhttps://hdl.handle.net/11147/6849
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Article Citation - WoS: 3Citation - Scopus: 10Hard color-singlet exchange in dijet events in proton-proton collisions at root s=13 TeV(Amer Physical Soc, 2021) Karapınar, GülerEvents where the two leading jets are separated by a pseudorapidity interval devoid of particle activity, known as jet-gap-jet events, are studied in proton-proton collisions at root s = 13 TeV. The signature is expected from hard color-singlet exchange. Each of the highest transverse momentum (p(T)) jets must have p(T)(jet) > 40 GeV and pseudorapidity 1.4 < vertical bar eta(jet)vertical bar < 4.7, with eta(jet1)eta(jet2) < 0, where jet1 and jet2 are the leading and subleading jets in p(T), respectively. The analysis is based on data collected by the CMS and TOTEM experiments during a low luminosity, high-beta* run at the CERN LHC in 2015, with an integrated luminosity of 0.66 pb(-1). Events with a low number of charged particles with p(T) > 0.2 GeV in the interval vertical bar eta vertical bar < 1 between the jets are observed in excess of calculations that assume only color-exchange. The fraction of events produced via color-singlet exchange, f(CSE), is measured as a function of p(T)(jet2), the pseudorapidity difference between the two leading jets, and the azimuthal angular separation between the two leading jets. The fraction f(CSE) has values of 0.4-1.0%. The results are compared with previous measurements and with predictions from perturbative quantum chromodynamics. In addition, the first study of jet-gap-jet events detected in association with an intact proton using a subsample of events with an integrated luminosity of 0.40 pb(-1) is presented. The intact protons are detected with the Roman pot detectors of the TOTEM experiment. The f(CSE) in this sample is 2.91 +/- 0.70(stat)(-1.01)(+1.08)(syst) times larger than that for inclusive dijet production in dijets with similar kinematics.Article Citation - WoS: 26Citation - Scopus: 43Measurement of Bose-Einstein Correlations in Pp Collisions at √s = 0.9 and 7 Tev(Springer Verlag, 2011) Khachatryan,V.; Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Bergauer,T.; Dragicevic,M.; Marchica,C.Bose-Einstein correlations between identical particles are measured in samples of proton-proton collisions at 0.9 and 7TeV centre-of-mass energies, recorded by the CMS experiment at the LHC. The signal is observed in the form of an enhancement of number of pairs of same-sign charged particles with small relative momentum. The dependence of this enhancement on kinematic and topological features of the event is studied. Anticorrelations between same-sign charged particles are observed in the region of relative momenta higher than those in the signal region.Article Citation - WoS: 41Citation - Scopus: 50Inclusive Search for Highly Boosted Higgs Bosons Decaying To Bottom Quark-Antiquark Pairs in Proton-Proton Collisions at ?s = 13 Tev(Springer Verlag, 2020) CMS Collaboration; Karapınar, GülerA search for standard model Higgs bosons (H) produced with transverse momentum (pT) greater than 450 GeV and decaying to bottom quark-antiquark pairs (b b ¯) is performed using proton-proton collision data collected by the CMS experiment at the LHC at s = 13 TeV. The data sample corresponds to an integrated luminosity of 137 fb?1. The search is inclusive in the Higgs boson production mode. Highly Lorentz-boosted Higgs bosons decaying to b b ¯ are reconstructed as single large-radius jets, and are identified using jet substructure and a dedicated b tagging technique based on a deep neural network. The method is validated with Z ?b b ¯ decays. For a Higgs boson mass of 125 GeV, an excess of events above the background assuming no Higgs boson production is observed with a local significance of 2.5 standard deviations (?), while the expectation is 0.7. The corresponding signal strength and local significance with respect to the standard model expectation are ?H = 3.7 ± 1.2(stat)?0.7+0.8(syst)?0.5+0.8(theo) and 1.9 ?. Additionally, an unfolded differential cross section as a function of Higgs boson pT for the gluon fusion production mode is presented, assuming the other production modes occur at the expected rates. [Figure not available: see fulltext.] © 2020, The Author(s).Article Citation - WoS: 56Citation - Scopus: 61First Measurement of Hadronic Event Shapes in Pp Collisions at S=7 Tev(Elsevier, 2011) Karapınar, GülerHadronic event shapes have been measured in proton–proton collisions at s=7 TeV, with a data sample collected with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 3.2 pb?1. Event-shape distributions, corrected for detector response, are compared with five models of QCD multijet production. © 2011 CERNArticle Citation - WoS: 103Citation - Scopus: 98Measurement of W+w Production and Search for the Higgs Boson in Pp Collisions at S=7 Tev(Elsevier Ltd., 2011) Karapınar, GülerA measurement of W+W? production in pp collisions at s=7 TeV and a search for the Higgs boson are reported. The W+W? candidates are selected in events with two leptons, either electrons or muons. The measurement is performed using LHC data recorded with the CMS detector, corresponding to an integrated luminosity of 36 pb?1. The pp ? W+W? cross section is measured to be 41.1±15.3(stat)±5.8(syst)±4.5(lumi)pb, consistent with the standard model prediction. Limits on WW? and WWZ anomalous triple gauge couplings are set. The search for the standard model Higgs boson in the W+W? decay mode does not reveal any evidence of excess above backgrounds. Limits are set on the production of the Higgs boson in the context of the standard model and in the presence of a sequential fourth family of fermions with high masses. In the latter context, a Higgs boson with mass between 144 and 207 GeV/c2 is ruled out at 95% confidence level. © 2011 CERNArticle Citation - WoS: 13Citation - Scopus: 15Design, Performance, and Calibration of the Cms Hadron-Outer Calorimeter(Springer Verlag, 2008) Karapınar, GülerThe Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E T measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS. © 2008 Springer-Verlag / Società Italiana di Fisica.Correction Citation - WoS: 4Citation - Scopus: 2Erratum: the Cms Barrel Calorimeter Response To Particle Beams From 2 To 350 Gev/C (the European Physical Journal C (2009) 60 (359-373) Doi: 10.1140/Epjc(Springer Verlag, 2009) Karapınar, Güler[No abstract available]