Ï(nS) polarizations versus particle multiplicity in pp collisions at s=7Â TeV
V. Khachatryan (Yerevan Physics Institute, Yerevan, Armenia); A.M. Sirunyan (Yerevan Physics Institute, Yerevan, Armenia); A. Tumasyan (Yerevan Physics Institute, Yerevan, Armenia); W. Adam (Institut für Hochenergiephysik der OeAW, Wien, Austria); E. Asilar (Institut für Hochenergiephysik der OeAW, Wien, Austria); et al - Show all 2284 authors
The polarizations of the Ï(1S) , Ï(2S) , and Ï(3S) mesons are measured as a function of the charged particle multiplicity in protonâproton collisions at s=7Â TeV . The measurements are performed with a dimuon data sample collected in 2011 by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb â1 . The results are extracted from the dimuon decay angular distributions, in two ranges of Ï(nS) transverse momentum (10â15 and 15â35 GeV), and in the rapidity interval |y|<1.2 . The results do not show significant changes from low- to high-multiplicity pp collisions, although large uncertainties preclude definite statements in the Ï(2S) and Ï(3S) cases.
