TY - JOUR N1 - This version is the version of record. For information on re-use, please refer to the publisher?s terms and conditions. VL - 99 A1 - Lancaster, M A1 - Nurse, E A1 - Waters, DCDFC JF - Physical Review Letters TI - Polarizations of J / ? and ? ( 2 S ) Mesons Produced in p ¯ p Collisions at ? s = 1.96 TeV Y1 - 2007/09/26/ SN - 0031-9007 AV - public IS - 13 N2 - We have measured the polarizations of J/? and ?(2S) mesons as functions of their transverse momentum pT when they are produced promptly in the rapidity range |y|<0.6 with pT?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 pT 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/? and ?(2S) mesons from B-hadron decays are also reported. ID - discovery131839 UR - http://dx.doi.org/10.1103/PhysRevLett.99.132001 ER -