Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 31Citation - Scopus: 44Angular Analysis of the Decay B+ → K+μ+μ- in Proton-Proton Collisions at √s=8 TeV(Amer Physical Soc, 2018) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Woods, N.The angular distribution of the flavor-changing neutral current decay B+ -> K+mu(+)mu(-) is studied in proton-proton collisions at a center-of-mass energy of 8 TeV. The analysis is based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 20.5 fb(-1). The forward-backward asymmetry A(FB) of the dimuon system and the contribution F-H from the pseudoscalar, scalar, and tensor amplitudes to the decay width are measured as a function of the dimuon mass squared. The measurements are consistent with the standard model expectations.Article Citation - WoS: 15Citation - Scopus: 18Search for Supersymmetry in pp Collisions at √s=13 TeV in the Single-Lepton Final State Using the Sum of Masses of Large-Radius Jets(Amer Physical Soc, 2017) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Woods, N.Results are reported from a search for supersymmetric particles in proton-proton collisions in the final state with a single lepton, multiple jets, including at least one b-tagged jet, and large missing transverse momentum. The search uses a sample of proton-proton collision data at root s = 13 TeV recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb(-1). The observed event yields in the signal regions are consistent with those expected from standard model backgrounds. The results are interpreted in the context of simplified models of supersymmetry involving gluino pair production, with gluino decay into either on- or off-mass-shell top squarks. Assuming that the top squarks decay into a top quark plus a stable, weakly interacting neutralino, scenarios with gluino masses up to about 1.9 TeV are excluded at 95% confidence level for neutralino masses up to about 1 TeV.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: 13Citation - Scopus: 16Observation of Bs 0 Mesons and Measurement of the Bs 0/B+ Yield Ratio in Pbpb Collisions at [formula Presented] Tev(Elsevier B.V., 2022) Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; Erö, J.; Kirakosyan, M.The Bs 0 and B+ production yields are measured in PbPb collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data sample, collected with the CMS detector at the LHC, corresponds to an integrated luminosity of 1.7 nb−1. The mesons are reconstructed in the exclusive decay channels B→s0J/ψ(μ+μ−)ϕ(K+K−) and B→+J/ψ(μ+μ−)K+, in the transverse momentum range 7–50 GeV/c and absolute rapidity 0–2.4. The Bs 0 meson is observed with a statistical significance in excess of five standard deviations for the first time in nucleus-nucleus collisions. The measurements are performed as functions of the transverse momentum of the B mesons and of the PbPb collision centrality. The ratio of production yields of Bs 0 and B+ is measured and compared to theoretical models that include quark recombination effects. © 2022 The Author(s)Article Citation - WoS: 15Citation - Scopus: 19Study of J/Ψ Meson Production Inside Jets in pp Collisions at S=8 TeV(Elsevier B.V., 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Hensel, C.A study of the production of prompt J/ψ mesons contained in jets in proton-proton collisions at s=8TeV is presented. The analysis is based on data corresponding to an integrated luminosity of 19.1 fb−1 collected with the CMS detector at the LHC. For events with at least one observed jet, the angular separation between the J/ψ meson and the jet is used to test whether the J/ψ meson is part of the jet. The analysis shows that most prompt J/ψ mesons having energy above 15 GeV and rapidity |y|<1 are contained in jets with pseudorapidity |η<inf>jet</inf>|<1. The differential distributions of the probability to have a J/ψ meson contained in a jet as a function of jet energy for a fixed J/ψ energy fraction are compared to a theoretical model using the fragmenting jet function approach. The data agree best with fragmenting jet function calculations that use a long-distance matrix element parameter set in which prompt J/ψ mesons are predicted to be unpolarized. This technique demonstrates a new way to test predictions for prompt J/ψ production using nonrelativistic quantum chromodynamics. © 2020 Elsevier B.V.Article Citation - WoS: 26Citation - Scopus: 27Measurement of the Azimuthal Anisotropy of [Formula Presented] and [Formula Presented] Mesons in PbPb Collisions at S NN =5.02 TeV(Elsevier B.V., 2021) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; De Jesus Damiao, D.The second-order Fourier coefficients (v<inf>2</inf>) characterizing the azimuthal distributions of [Formula presented] and [Formula presented] mesons produced in PbPb collisions at s<inf> <inf>NN</inf> </inf>=5.02TeV are studied. The [Formula presented] mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of 1.7nb−1. The scalar product method is used to extract the v<inf>2</inf> coefficients of the azimuthal distributions. Results are reported for the rapidity range |y|<2.4, in the transverse momentum interval 0<p<inf>T</inf><50GeV/c, and in three centrality ranges of 10–30%, 30–50% and 50–90%. In contrast to the J/ψ mesons, the measured v<inf>2</inf> values for the [Formula presented] mesons are found to be consistent with zero. © 2021 The Author(s)Article Citation - WoS: 107Citation - Scopus: 153Evidence for Higgs Boson Decay To a Pair of Muons(Springer, 2021) Karapınar, Güler; CMS Collaboration; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Salama, E.Evidence for Higgs boson decay to a pair of muons is presented. This result combines searches in four exclusive categories targeting the production of the Higgs boson via gluon fusion, via vector boson fusion, in association with a vector boson, and in association with a top quark-antiquark pair. The analysis is performed using proton-proton collision data at root s = 13 TeV, corresponding to an integrated luminosity of 137 fb(-1), recorded by the CMS experiment at the CERN LHC. An excess of events over the back- ground expectation is observed in data with a significance of 3.0 standard deviations, where the expectation for the standard model (SM) Higgs boson with mass of 125.38 GeV is 2.5. The combination of this result with that from data recorded at root s = 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb(-1), respectively, increases both the expected and observed significances by 1%. The measured signal strength, relative to the SM prediction, is 1.19(-0.39)(+0.40)(stat)(-0.14)(+0.15). This result constitutes the first evidence for the decay of the Higgs boson to second generation fermions and is the most precise measurement of the Higgs boson coupling to muons reported to date.Article Citation - WoS: 91Citation - Scopus: 133Measurements of T T ¯ H Production and the Cp Structure of the Yukawa Interaction Between the Higgs Boson and Top Quark in the Diphoton Decay Channel(American Physical Society, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; Skovpen, Y.The first observation of the tt¯H process in a single Higgs boson decay channel with the full reconstruction of the final state (H→γγ) is presented, with a significance of 6.6 standard deviations (σ). The CP structure of Higgs boson couplings to fermions is measured, resulting in an exclusion of the pure CP-odd structure of the top Yukawa coupling at 3.2σ. The measurements are based on a sample of proton-proton collisions at a center-of-mass energy s=13 TeV collected by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb-1. The cross section times branching fraction of the tt¯H process is measured to be σtt¯HBγγ=1.56-0.32+0.34 fb, which is compatible with the standard model prediction of 1.13-0.11+0.08 fb. The fractional contribution of the CP-odd component is measured to be fCPHtt=0.00±0.33. © 2020 CERN.Article Citation - WoS: 8Citation - Scopus: 17Measurement of the Associated Production of a Z Boson With Charm or Bottom Quark Jets in Proton-Proton Collisions at S =13 Tev(American Physical Society, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Tyurin, N.Ratios of cross sections, σ(Z+c jets)/σ(Z+jets), σ(Z+b jets)/σ(Z+jets), and σ(Z+c jets)/σ(Z+b jets) in the associated production of a Z boson with at least one charm or bottom quark jet are measured in proton-proton collisions at s=13 TeV. The data sample, collected by the CMS experiment at the CERN LHC, corresponds to an integrated luminosity of 35.9 fb-1, with a fiducial volume of pT>30 GeV and |η|<2.4 for the jets, where pT and η represent transverse momentum and pseudorapidity, respectively. The Z boson candidates come from leptonic decays into electrons or muons with pT>25 GeV and |η|<2.4, and the dilepton mass satisfies 71<mZ<111 GeV. The measured values are σ(Z+c jets)/σ(Z+jets)=0.102±0.002±0.009, σ(Z+b jets)/σ(Z+jets)=0.0633±0.0004±0.0015, and σ(Z+c jets)/σ(Z+b jets)=1.62±0.03±0.15. Results on the inclusive and differential cross section ratios as functions of jet and Z boson transverse momentum are compared with predictions from leading and next-to-leading order perturbative quantum chromodynamics calculations. These are the first measurements of the cross section ratios at 13 TeV. © 2020 American Physical Society. All rights reserved.Article Citation - WoS: 15Citation - Scopus: 16Studies of Charm Quark Diffusion Inside Jets Using Pb-Pb and Pp Collisions at Snn =5.02 Tev(American Physical Society, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Devetak, D.The first study of charm quark diffusion with respect to the jet axis in heavy ion collisions is presented. The measurement is performed using jets with pTjet>60 GeV/c and D0 mesons with pTD>4 GeV/c in lead-lead (Pb-Pb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of sNN=5.02 TeV, recorded by the CMS detector at the LHC. The radial distribution of D0 mesons with respect to the jet axis is sensitive to the production mechanisms of the meson, as well as to the energy loss and diffusion processes undergone by its parent parton inside the strongly interacting medium produced in Pb-Pb collisions. When compared to Monte Carlo event generators, the radial distribution in pp collisions is found to be well described by pythia, while the slope of the distribution predicted by sherpa is steeper than that of the data. In Pb-Pb collisions, compared to the pp results, the D0 meson distribution for 4<pTD<20 GeV/c hints at a larger distance on average with respect to the jet axis, reflecting a diffusion of charm quarks in the medium created in heavy ion collisions. At higher pTD, the Pb-Pb and pp radial distributions are found to be similar. © 2020 CERN.