@article{discovery131839,
            note = {This version is the version of record. For information on re-use, please refer to the publisher's terms and conditions.},
            year = {2007},
           month = {September},
          volume = {99},
           title = {Polarizations of J / {\ensuremath{\psi}} and {\ensuremath{\psi}} ( 2 S ) Mesons Produced in p ? p Collisions at {$\sqrt$} s = 1.96 TeV},
          number = {13},
         journal = {Physical Review Letters},
            issn = {0031-9007},
          author = {Lancaster, M and Nurse, E and Waters, DCDFC},
             url = {http://dx.doi.org/10.1103/PhysRevLett.99.132001},
        abstract = {We have measured the polarizations of J/{\ensuremath{\psi}} and {\ensuremath{\psi}}(2S) mesons as functions of their transverse momentum pT when they are produced promptly in the rapidity range {\ensuremath{|}}y{\ensuremath{|}}{\ensuremath{<}}0.6 with pT{$\ge$}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/{\ensuremath{\psi}} and {\ensuremath{\psi}}(2S) mesons from B-hadron decays are also reported.}
}