Inclusive double-quarkonium production at the Large Hadron Collider

TL;DR

This paper predicts inclusive double-quarkonium production rates at the LHC using NRQCD, including both color-singlet and color-octet channels, and highlights the potential of J/psi+Upsilon production to probe the color-octet mechanism.

Contribution

It provides comprehensive predictions for double-quarkonium production at the LHC without relying on fragmentation approximation, including both color-singlet and octet contributions at leading order.

Findings

Predicted total production rates for various double-quarkonium states.

Color-singlet dominates low-p_T for J/psi+J/psi and Upsilon+Upsilon.

J/psi+Upsilon production probes the color-octet mechanism.

Abstract

Based on the nonrelativistic QCD (NRQCD) factorization formalism, we investigate inclusive productions of two spin-triplet S-wave quarkonia pp->2J/psi+X, 2Upsilon+X, and J/psi+Upsilon+X at the CERN Large Hadron Collider. The total production rates integrated over the rapidity (y) and transverse-momentum (p_T) ranges |y|<2.4 and p_T<50 GGeV are predicted to be sigma[pp->2J/psi+X] = 22 (35) nb, sigma[pp->2Upsilon+X] = 24 (49) pb, and sigma[pp->J/psi+Upsilon+X] = 7 (13) pb at the center-of-momentum energy sqrt{s} = 7 (14) TeV. In order to provide predictions that can be useful in both small- and large-p_T regions, we do not employ the fragmentation approximation and we include the spin-triplet S-wave color-singlet and color-octet channels for each quarkonium final state at leading order in the strong coupling. The p_T distributions of pp->2J/psi+X and 2Upsilon+X in the low-p_T region are dominated by the color-singlet contributions. At leading order in the strong coupling, the color-singlet channel is absent for pp->J/psi+Upsilon+X. Therefore, the process pp->J/psi+Upsilon+X may provide a useful probe to the color-octet mechanism of NRQCD.