PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 20Citation - Scopus: 31Search for Flavor-Changing Neutral Current Interactions of the Top Quark and Higgs Boson in Final States With Two Photons in Proton-Proton Collisions at S =13 Tev(American Physical Society, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Bunichev, V.; 01. Izmir Institute of TechnologyProton-proton interactions resulting in final states with two photons are studied in a search for the signature of flavor-changing neutral current interactions of top quarks (t) and Higgs bosons (H). The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb-1. No significant excess above the background prediction is observed. Upper limits on the branching fractions (B) of the top quark decaying to a Higgs boson and an up (u) or charm (c) quark are derived through a binned fit to the diphoton invariant mass spectrum. The observed (expected) 95% confidence level upper limits are found to be 0.019% (0.031%) for B(t→Hu) and 0.073% (0.051%) for B(t→Hc). These are the strictest upper limits yet determined. © 2022 CERN.Article Citation - WoS: 22Citation - Scopus: 25Observation of the Bc+ Meson in Pb-Pb and Pp Collisions at Snn =5.02 Tev and Measurement of Its Nuclear Modification Factor(American Physical Society, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Boos, E.; 01. Izmir Institute of TechnologyThe Bc+ meson is observed for the first time in heavy ion collisions. Data from the CMS detector are used to study the production of the Bc+ meson in lead-lead (Pb-Pb) and proton-proton (pp) collisions at a center-of-mass energy per nucleon pair of sNN=5.02 TeV, via the Bc+→(J/ψ→μ+μ-)μ+νμ decay. The Bc+ nuclear modification factor, derived from the Pb-Pb-to-pp ratio of production cross sections, is measured in two bins of the trimuon transverse momentum and of the Pb-Pb collision centrality. The Bc+ meson is shown to be less suppressed than quarkonia and most of the open heavy-flavor mesons, suggesting that effects of the hot and dense nuclear matter created in heavy ion collisions contribute to its production. This measurement sets forth a promising new probe of the interplay of suppression and enhancement mechanisms in the production of heavy-flavor mesons in the quark-gluon plasma. © 2022 CERN.Article Citation - WoS: 33Citation - Scopus: 52Observation of the Production of Three Massive Gauge Bosons at S =13 Tev(American Physical Society, 2020) Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Dremin,I.; 01. Izmir Institute of TechnologyThe first observation is reported of the combined production of three massive gauge bosons (VVV with V=W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb-1. The searches for individual WWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combined VVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02-0.23+0.26. The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported. © 2020 CERN.Article Citation - WoS: 12Citation - Scopus: 32Observation of the Bs0 →x (3872)φ Decay(American Physical Society, 2020) Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Andreev,V.; 01. Izmir Institute of TechnologyUsing a data sample of proton-proton collisions at s=13 TeV, corresponding to an integrated luminosity of 140 fb-1 collected by the CMS experiment in 2016-2018, the Bs0→X(3872)φ decay is observed. Decays into J/ψ+π- and K+K- are used to reconstruct, respectively, the X(3872) and φ. The ratio of the product of branching fractions B[Bs0→X(3872)φ]B[X(3872)→J/ψ+π-] to the product B[Bs0→(2S)φ]B[ψ(2S)→J/ψ+π-] is measured to be [2.21±0.29(stat)±0.17(syst)]%. The ratio B[Bs0→X(3872)φ]/B[B0→X(3872)K0] is found to be consistent with one, while the ratio B[Bs0→X(3872)φ]/B[B+→X(3872)K+] is two times smaller. This suggests a difference in the production dynamics of the X(3872) in B0 and Bs0 meson decays compared to B+. The reported observation may shed new light on the nature of the X(3872) particle. © 2020 CERN.