Next-to-leading-order QCD corrections to double prompt $J/{\psi}$ hadroproduction

TL;DR

This paper calculates next-to-leading-order QCD corrections to prompt $J/\psi$ pair production within NRQCD, comparing predictions with LHC data and highlighting the limitations of the color singlet model.

Contribution

It provides the first comprehensive NLO analysis of the color singlet contribution to $J/\psi$ pair production at the LHC, including detailed comparison with experimental data.

Findings

CS contribution describes LHCb data well in most regions

CS predictions underestimate CMS and ATLAS total and differential cross sections

NLO corrections increase the predicted cross sections by factors of 2-3

Abstract

Within the framework of nonrelativistic-QCD (NRQCD) factorization, we perform a comprehensive investigation of the color singlet (CS) contribution to prompt $J/\psi$ pair production at the CERN Large Hadron Collider at next-to-leading order (NLO) in $\alpha_s$. Specifically, we compare our NLO predictions with measurements from the LHCb, CMS, and ATLAS Collaborations. We find that the CS contribution itself can well describe the LHCb data in most of the experimental bins, except in the regions where the fixed-order calculation is spoiled by the emission of soft or hard-collinear gluons. In the CMS and ATLAS cases, however, the CS predictions greatly undershoot both the measured total and differential cross sections, despite sizable $K$ factors, of 2--3, for the total cross sections.