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: 86Citation - Scopus: 109Study of Z Boson Production in Pbpb Collisions at ?s Nn=2.76tev(American Physical Society, 2011) Karapınar, Güler; Karapınar, Güler; Demir, Durmuş Ali; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceA search for Z bosons in the μ+μ- decay channel has been performed in PbPb collisions at √sNN=2.76TeV with the CMS detector at the LHC, in a 7.2μb-1 data sample. The number of opposite-sign muon pairs observed in the 60-120GeV/c2 invariant mass range is 39, corresponding to a yield per unit of rapidity (y) and per minimum bias event of [33.8±5.5(stat)±4.4(syst)]×10-8, in the |y|<2.0 range. Rapidity, transverse momentum, and centrality dependencies are also measured. The results agree with next-to-leading order QCD calculations, scaled by the number of incoherent nucleon-nucleon collisions. © 2011 American Physical Society.Article Citation - WoS: 243Citation - Scopus: 216Indications of Suppression of Excited? States in Pb-Pb Collisions at Snn2.76 Tev(American Physical Society, 2011) Karapınar, Güler; Demir, Durmuş Ali; Karapınar, Güler; 04.05. Department of Pyhsics; 01. Izmir Institute of Technology; 04. Faculty of ScienceA comparison of the relative yields of Υ resonances in the μ+μ- decay channel in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair of 2.76TeV is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4GeV/c and pseudorapidity below 2.4, the double ratio of the Υ(2S) and Υ(3S) excited states to the Υ(1S) ground state in Pb-Pb and pp collisions, [Υ(2S+3S)/Υ(1S)]Pb-Pb/[Υ(2S+3S)/Υ(1S) ]pp, is found to be 0.31-0.15+0.19(stat)±0.03(syst). The probability to obtain the measured value, or lower, if the true double ratio is unity, is calculated to be less than 1%. © 2011 American Physical Society.