The remaining parts for the long-standing J/psi polarization puzzle

Abstract

Based on the non-relativistic quantum chromodynamics factorization formalism, the polarization parameters $\hat{I}{»}_{\hat{I}¸\ddot{I}•}$ and $\hat{I}{»}_{\ddot{I}}•$ of $J/\ddot{I}ˆ$ hadroproduction are analyzed in helicity frame and calculated at QCD next-to-leading order for the first time. For prompt $J/\ddot{I}ˆ$ production, we take into account the feeddown contributions from $\ddot{I}{‡}_{cJ}$ and $\ddot{I}ˆ(2S)$ decays. The theoretical predictions for the polarization parameters $\hat{I}{»}_{\hat{I}¸\ddot{I}•}$ and $\hat{I}{»}_{\ddot{I}}•$ of $J/\ddot{I}ˆ$ are presented. With the theoretical results we have done the fit to the experimental measurements on yield and polarization for $J/\ddot{I}ˆ$ hadroproduction simultaneously, and found that the results are coincide with the experimental measurements at the LHC quite well.

5 pages, 4 figures