Next-To-Leading Order Differential Cross-Sections for $J/\psi$, $\psi(2S)$ and $\Upsilon$ Production in Proton-Proton Collisions at a Fixed-Target Experiment using the LHC Beams (AFTER@LHC)

TL;DR

This paper calculates next-to-leading order differential cross-sections for quarkonium production in proton-proton fixed-target experiments using LHC beams, providing theoretical predictions and uncertainty estimates relevant for upcoming measurements.

Contribution

It presents NLO QCD calculations of quarkonium production cross-sections at fixed-target energies using NRQCD, including uncertainty analysis based on different long-distance matrix elements.

Findings

NLO cross-sections are computed for $J/\psi$, $\psi(2S)$, and $\Upsilon$ production.

Theoretical uncertainties exceed projected experimental errors.

Results are relevant for future fixed-target experiments with LHC beams.

Abstract

Using nonrelativistic QCD (NRQCD) factorization, we calculate the yields for $J/\psi$, $\psi(2S)$ and $\Upsilon(1S)$ hadroproduction at $\sqrt{s}=$ 72 GeV and 115 GeV including the next-to-leading order QCD corrections. Both these center-of-mass energies correspond to those obtained with 7~TeV and 2.76~TeV nucleon beam impinging a fixed target. We study the cross section integrated in $p_t$ as a function of the rapidity as well as the $p_t$ differential cross section in the central rapidity region. Using different NLO fit results of the NRQCD long-distance matrix elements, we evaluate a theoretical uncertainty which is certainly much larger than the projected experimental uncertainties with the expected 20 fb$^{-1}$ to be collected per year with AFTER@LHC.