Polarizations ofJ/ψandψ(2S)Mesons Produced inpp¯Collisions ats=1.96 TeV

We have measured the polarizations of $J/\ensuremath{\psi}$ and $\ensuremath{\psi}(2S)$ mesons as functions of their transverse momentum ${p}_{T}$ when they are produced promptly in the rapidity range $|y|<0.6$ with ${p}_{T}\ensuremath{\ge}5\text{ }\text{ }\mathrm{GeV}/c$. The analysis is performed using a data sample with an integrated luminosity of about $800\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ 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 $30\text{ }\text{ }\mathrm{GeV}/c$. 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.

Polarizations ofJ/ψandψ(2S)Mesons Produced inpp¯Collisions ats=1.96 TeV | Litlas