Upsilonium polarization as a touchstone in understanding the proton dynamics in QCD

Abstract

In the framework of the k_t-factorization approach, the production of ${\rm Y}mesonsattheFermilabTevatronandCERNLHCisconsidered,andthepredictionsonthespinalignmentparameter$\alpha$ are presented. We argue that measuring the polarization of quarkonium states can serve as a crucial test discriminating two competing theoretical approaches to parton dynamics in QCD.

Comments: 8 pages, 2 figures