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

TL;DR

This paper investigates the polarization of Upsilon mesons in high-energy collisions using the k_t-factorization approach, proposing that quarkonium polarization measurements can distinguish between different QCD models.

Contribution

It introduces polarization predictions within the k_t-factorization framework and emphasizes the importance of polarization measurements to test QCD parton dynamics models.

Findings

Predictions for the spin alignment parameter α at Tevatron and LHC.

Polarization measurements can discriminate between competing QCD approaches.

Highlights the role of quarkonium polarization as a test of parton dynamics.

Abstract

In the framework of the k_t-factorization approach, the production of $\Upsilon mesons at the Fermilab Tevatron and CERN LHC is considered, and the predictions on the spin alignment parameter $\alpha$ 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.