Beauty-quark and charm-quark pair production asymmetries at LHCb

TL;DR

This paper provides the standard model predictions for beauty and charm quark pair production asymmetries at LHCb, showing good agreement with recent experimental data and suggesting new ways to validate charm-tagging efficiencies.

Contribution

It offers the first fixed-order perturbative calculations of beauty and charm quark asymmetries at LHCb, aligning with recent measurements and proposing cross section ratios for experimental validation.

Findings

Good agreement between predictions and LHCb data for beauty asymmetry.

Predictions for charm-quark asymmetries within LHCb acceptance.

Proposal to use cross section ratios to validate charm-tagging efficiencies.

Abstract

The LHCb collaboration has recently performed a first measurement of the angular production asymmetry in the distribution of beauty quarks and anti-quarks at a hadron collider. We calculate the corresponding standard model prediction for this asymmetry at fixed-order in perturbation theory. Our results show good agreement with the data, which is provided differentially for three bins in the invariant mass of the $b \bar b$ system. We also present similar predictions for both beauty-quark and charm-quark final states within the LHCb acceptance for a collision energy of $\sqrt{s} = 13 \, {\rm TeV}$. We finally point out that a measurement of the ratio of the $b \bar b$ and $c \bar c$ cross sections may be useful for experimentally validating charm-tagging efficiencies.