We have measured the polarizations of J/psi and psi(2S) mesons as functions of their transverse momentum p(T) when they are produced promptly in the rapidity range |y|< 0.6 with p(T)>= 5 GeV/c. The analysis is performed using a data sample with an integrated luminosity of about 800 pb(-1) collected by the CDF II detector. For both vector mesons, we find that the polarizations become increasingly longitudinal as p(T) increases from 5 to 30 GeV/c. These results are compared to the predictions of nonrelativistic quantum chromodynamics and other contemporary models. The effective polarizations of J/psi and psi(2S) mesons from B-hadron decays are also reported.
|Titolo:||Polarizations of J/psi and psi(2S) mesons produced in p(p)over-bar collisins at root s-1.96 TeV RID G-1087-2011 RID E-4473-2011|
|Data di pubblicazione:||2007|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1103/PhysRevLett.99.132001|
|Appare nelle tipologie:||1.1 Articolo in rivista|