$\Upsilon(nS)$ and $\chi_b(nP)$ production at hadron colliders in nonrelativistic QCD

TL;DR

This paper analyzes the production and polarization of bottomonium states at the LHC using nonrelativistic QCD, incorporating feeddown effects and extracting long-distance matrix elements to match experimental data.

Contribution

It provides a comprehensive NLO QCD analysis of $(nS)$ and $_b(nP)$ production, including feeddown effects, and successfully explains polarization puzzles.

Findings

Predicted $(nS)$ polarizations agree with measurements within errors.

Large feeddown from $_b(3P)$ states explains the $(3S)$ polarization puzzle.

Results describe cross sections and polarizations of prompt bottomonium at the LHC.

Abstract

$\Upsilon(nS)$ and $\chi_b(nP)$ (n=1,2,3) production at the LHC is studied at next-to-leading order in $\alpha_s$ in nonrelativistic QCD. Feeddown contributions from higher $\chi_b$ and $\Upsilon$ states are all considered for lower $\Upsilon$ cross sections and polarizations. The long distance matrix elements (LDMEs) are extracted from the yield data, and then used to make predictions for the $\Upsilon(nS)$ polarizations, which are found to be consistent with the measured polarization data within errors. In particular, the $\Upsilon(3S)$ polarization puzzle can be understood by a large feeddown contribution from $\chi_b(3P)$ states. Our results may provide a good description for both cross sections and polarizations of prompt $\Upsilon(nS)$ and $\chi_b(nP)$ production at the LHC.