J/psi polarization at hadron colliders in nonrelativistic QCD

Paper

Abstract

With nonrelativistic QCD factorization, we present a full next-to-leading order computation of the polarization observable for

production at hadron colliders including all important Fock states, i.e.

, and

. We find the

channel contributes a positive longitudinal component and a negative transverse component. So the

polarization puzzle may be understood as the transverse components canceling between

and

channels, which results in mainly the unpolarized (even slightly longitudinally polarized)

. This may give a possible solution to the long-standing

polarization puzzle. Predictions for

polarization at the LHC are also presented.