Production and polarization of direct J/ψ to O(αs3) in the improved color evaporation model in collinear factorization

We calculate the production and polarization of direct J/psi in the improved color evaporation model at O(alpha(3)(s)) in the collinear factorization approach. We present the first calculation of polarization parameters lambda(theta), lambda(phi), and lambda(theta phi) in the helicity and the Collins-Soper frames as well as the frame-invariant polarization parameter (lambda) over tilde as a function of transverse momentum. We find agreement with both J/psi cross sections and the invariant polarization parameters at small and moderate p(T).

Automated summary

In the improved color evaporation model, we calculated the production and polarization of direct J/psi at O(alpha(3)(s)) in the collinear factorization approach. Our findings show agreement between J/psi cross sections and invariant polarization parameters at small and moderate transverse momentum.