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

Abstract

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

5 pages, 4 figures