Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
7 results
Search Results
Article Citation - WoS: 86Citation - Scopus: 8Measurement of Single-Diffractive Dijet Production in Proton–proton Collisions at √s=8te With the Cms and Totem Experiments(Springer Nature, 2020) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Josa, M.I.Measurements are presented of the single-diffractive dijet cross section and the diffractive cross section as a function of the proton fractional momentum loss ξ and the four-momentum transfer squared t. Both processes pp→pX and pp→Xp, i.e. with the proton scattering to either side of the interaction point, are measured, where X includes at least two jets; the results of the two processes are averaged. The analyses are based on data collected simultaneously with the CMS and TOTEM detectors at the LHC in proton–proton collisions at s=8Te during a dedicated run with β∗=90m at low instantaneous luminosity and correspond to an integrated luminosity of 37.5nb-1. The single-diffractive dijet cross section σjjpX, in the kinematic region ξ< 0.1 , 0.03<|t|<1Ge2, with at least two jets with transverse momentum pT>40Ge, and pseudorapidity | η| < 4.4 , is 21.7±0.9(stat)-3.3+3.0(syst)±0.9(lumi)nb. The ratio of the single-diffractive to inclusive dijet yields, normalised per unit of ξ, is presented as a function of x, the longitudinal momentum fraction of the proton carried by the struck parton. The ratio in the kinematic region defined above, for x values in the range - 2.9 ≤ log 10x≤ - 1.6 , is R=(σjjpX/Δξ)/σjj=0.025±0.001(stat)±0.003(syst), where σjjpX and σjj are the single-diffractive and inclusive dijet cross sections, respectively. The results are compared with predictions from models of diffractive and nondiffractive interactions. Monte Carlo predictions based on the HERA diffractive parton distribution functions agree well with the data when corrected for the effect of soft rescattering between the spectator partons. © 2020, CERN for the benefit of the CMS and TOTEM collaborations.Article Citation - WoS: 6Citation - Scopus: 10Study of Central Exclusive [inlineequation Not Available: See Fulltext.] Production in Proton-Proton Collisions at √s=5.02 and 13tev(Springer Nature, 2020) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Kachanov, V.Central exclusive and semiexclusive production of [InlineEquation not available: see fulltext.] pairs is measured with the CMS detector in proton-proton collisions at the LHC at center-of-mass energies of 5.02 and 13TeV. The theoretical description of these nonperturbative processes, which have not yet been measured in detail at the LHC, poses a significant challenge to models. The two pions are measured and identified in the CMS silicon tracker based on specific energy loss, whereas the absence of other particles is ensured by calorimeter information. The total and differential cross sections of exclusive and semiexclusive central [InlineEquation not available: see fulltext.] production are measured as functions of invariant mass, transverse momentum, and rapidity of the [InlineEquation not available: see fulltext.] system in the fiducial region defined as transverse momentum [InlineEquation not available: see fulltext.] and pseudorapidity [InlineEquation not available: see fulltext.]. The production cross sections for the four resonant channels [InlineMediaObject not available: see fulltext.], [InlineEquation not available: see fulltext.], [InlineMediaObject not available: see fulltext.], and [InlineMediaObject not available: see fulltext.]are extracted using a simple model. These results represent the first measurement of this process at the LHC collision energies of 5.02 and 13TeV. © 2020, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 29Citation - Scopus: 33Measurement of the Jet Mass in Highly Boosted T T ¯ Events From Pp Collisions at √s=8tev(Springer Nature, 2017) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Baillon, P.The first measurement of the jet mass mjet of top quark jets produced in t t ¯ events from pp collisions at s=8TeV is reported for the jet with the largest transverse momentum pT in highly boosted hadronic top quark decays. The data sample, collected with the CMS detector, corresponds to an integrated luminosity of 19.7fb-1. The measurement is performed in the lepton+jets channel in which the products of the semileptonic decay t → b W with W → ℓν where ℓ is an electron or muon, are used to select t t ¯ events with large Lorentz boosts. The products of the fully hadronic decay t → b W with W → q q ¯ ′ are reconstructed using a single Cambridge–Aachen jet with distance parameter R= 1.2 , and pT> 400 GeV. The t t ¯ cross section as a function of mjet is unfolded at the particle level and is used to test the modelling of highly boosted top quark production. The peak position of the mjet distribution is sensitive to the top quark mass mt, and the data are used to extract a value of mt to assess this sensitivity. © 2017, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 56Citation - Scopus: 70Search for Standard Model Production of Four Top Quarks With Same-Sign and Multilepton Final States in Proton–proton Collisions at √s=13tev(Springer Nature, 2018) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Romero, L.A search for standard model production of four top quarks (t t ¯ t t ¯) is reported using events containing at least three leptons (e , μ) or a same-sign lepton pair. The events are produced in proton–proton collisions at a center-of-mass energy of 13TeV at the LHC, and the data sample, recorded in 2016, corresponds to an integrated luminosity of 35.9fb-1. Jet multiplicity and flavor are used to enhance signal sensitivity, and dedicated control regions are used to constrain the dominant backgrounds. The observed and expected signal significances are, respectively, 1.6 and 1.0 standard deviations, and the t t ¯ t t ¯ cross section is measured to be 16.9-11.4+13.8fb, in agreement with next-to-leading-order standard model predictions. These results are also used to constrain the Yukawa coupling between the top quark and the Higgs boson to be less than 2.1 times its expected standard model value at 95% confidence level. © 2018, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 88Citation - Scopus: 114Measurement of Prompt and Nonprompt Charmonium Suppression in Pbpb Collisions at 5.02 Tev(Springer Nature, 2018) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Campderros, J.D.The nuclear modification factors of J / ψ and ψ(2S) mesons are measured in PbPb collisions at a centre-of-mass energy per nucleon pair of sNN=5.02TeV. The analysis is based on PbPb and p p data samples collected by CMS at the LHC in 2015, corresponding to integrated luminosities of 464μb-1 and 28pb-1, respectively. The measurements are performed in the dimuon rapidity range of | y| < 2.4 as a function of centrality, rapidity, and transverse momentum (pT) from pT= 3 GeV/c in the most forward region and up to 50GeV/c. Both prompt and nonprompt (coming from b hadron decays) J / ψ mesons are observed to be increasingly suppressed with centrality, with a magnitude similar to the one observed at sNN=2.76TeV for the two J / ψ meson components. No dependence on rapidity is observed for either prompt or nonprompt J / ψ mesons. An indication of a lower prompt J / ψ meson suppression at pT> 25 GeV/c is seen with respect to that observed at intermediate pT. The prompt ψ(2S) meson yield is found to be more suppressed than that of the prompt J / ψ mesons in the entire pT range. © 2018, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 42Citation - Scopus: 50Measurement of the Top Quark Mass With Lepton+jets Final States Using P P Collisions at √s=13tev(Springer Nature, 2018) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Ramos, J.P.F.The mass of the top quark is measured using a sample of t t ¯ events collected by the CMS detector using proton-proton collisions at s=13TeV at the CERN LHC. Events are selected with one isolated muon or electron and at least four jets from data corresponding to an integrated luminosity of 35.9fb-1. For each event the mass is reconstructed from a kinematic fit of the decay products to a t t ¯ hypothesis. Using the ideogram method, the top quark mass is determined simultaneously with an overall jet energy scale factor (JSF), constrained by the mass of the W boson in q q ¯ ′ decays. The measurement is calibrated on samples simulated at next-to-leading order matched to a leading-order parton shower. The top quark mass is found to be 172.25±0.08(stat+JSF)±0.62(syst)GeV. The dependence of this result on the kinematic properties of the event is studied and compared to predictions of different models of t t ¯ production, and no indications of a bias in the measurements are observed. © 2018, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 49Citation - Scopus: 55Measurement of Exclusive Ρ(770)0 Photoproduction in Ultraperipheral Ppb Collisions at √snn=5.02te(Springer Nature, 2019) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Bachiller, I.Exclusive ρ(770)0 photoproduction is measured for the first time in ultraperipheral pPb collisions at sNN=5.02Te with the CMS detector. The cross section σ(γp→ρ(770)0p) is 11.0±1.4(stat)±1.0(syst)μb at ⟨Wγp⟩=92.6Ge for photon–proton centre-of-mass energies Wγp between 29 and 213Ge. The differential cross section d σ/ d | t| is measured in the interval 0.025<|t|<1Ge2 as a function of Wγp, where t is the squared four-momentum transfer at the proton vertex. The results are compared with previous measurements and theoretical predictions. The measured cross section σ(γp→ρ(770)0p) has a power-law dependence on the photon–proton centre-of-mass, consistent with electron–proton collision measurements performed at HERA. The Wγp dependence of the exponential slope of the differential cross section d σ/ d | t| is also measured. © 2019, CERN for the benefit of the CMS collaboration.