Measurement of inclusive J/$\psi$ polarization in p+p collisions at $\sqrt{s}$ = 200 GeV by the STAR experiment

We report on new measurements of inclusive J/$\\psi$ polarization at mid-rapidity in p+p collisions at $\\sqrt{s}$ = 200 GeV by the STAR experiment at RHIC. The polarization parameters, $\\lambda_\\theta$, $\\lambda_\\phi$, and $\\lambda_{\\theta\\phi}$, are measured as a function of transverse momentum ($p_T$) in both the Helicity and Collins-Soper (CS) reference frames within $p_T\u003c 10$ GeV/$C$. Except for $\\lambda_\\theta$ in the CS frame at the highest measured $p_T$, all three polarization parameters are consistent with 0 in both reference frames without any strong $p_T$ dependence. Several model calculations are compared with data, and the one using the Color Glass Condensate effective field theory coupled with non-relativistic QCD gives the best overall description of the experimental results, even though other models cannot be ruled out due to experimental uncertainties.