Charmonium Polarization in High Energy Collisions

We consider charmonium polarization at high-energy hadron collider Tevatron in the framework of the nonrelativistic QCD (NRQCD) and the kT -factorization approach. The polarization effects are studied for the direct and the prompt production channels. The obtained predictions can be used for test of the Regge limit of QCD and for test of the NRQCD formalism. High-energy factorization In the phenomenology of strong interactions at high energy it is needed to describe the QCD evolution of gluon distribution functions in colliding particles starting from the scale μ0, which controls a nonperturbative regime, to the typical scale of hard scattering processes μ ∼MT = √ M2 + |pT |2, where MT is the transverse mass of the produced in a hard process particle. In the region of very high energies x = μ √ S ≪ 1. This fact leads to the big logarithmic contributions ∼ (αs log(1/x)) n in the resummation procedure, which is described by the BFKL [1] evolution equation for an unintegrated gluon distribution function Φ(x, |kT | , μ). In the kT -factorization approach [2] hadronic σ(p+p→ H+X) and partonic σ̂(R+R → H +X) cross sections are connected as follows: dσ(p+ p→ H +X,S) = ∫ dx1 x1 ∫ d|k1T | 2 ∫ dφ1 2π Φ(x1, |k1T | , μ)×