J/psi polarization at Tevatron and LHC: Nonrelativistic-QCD factorization at the crossroads
Abstract
We study the polarization observables of J/psi hadroproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics. We complete the present knowledge of the relativistic corrections by also providing the contribution due to the intermediate ^3P_J^{[8]} color-octet states at this order, which turns out to be quite significant. Exploiting the color-octet long-distance matrix elements previously extracted through a global fit to experimental data of unpolarized J/psi production, we provide theoretical predictions in the helicity and Collins-Soper frames and compare them with data taken by CDF at Fermilab Tevatron I and II and by ALICE at CERN LHC. The notorious CDF J/psi polarization anomaly familiar from leading-order analyses persists at the quantum level, while the situation looks promising for the LHC, which is bound to bring final clarification.
Cite
@article{arxiv.1201.1872,
title = {J/psi polarization at Tevatron and LHC: Nonrelativistic-QCD factorization at the crossroads},
author = {Mathias Butenschoen and Bernd A. Kniehl},
journal= {arXiv preprint arXiv:1201.1872},
year = {2015}
}
Comments
8 pages, 2 figures; minor changes to the text, 3 references added; accepted for publication in Physical Review Letters