J/psi+Z production at the LHC

TL;DR

This paper analyzes J/psi+Z production at the LHC, comparing theoretical predictions with experimental data, and finds evidence for significant double-parton scattering contributions, along with new one-loop QCD corrections to the model.

Contribution

It introduces the first computation of one-loop QCD corrections to J/psi production in the Colour Evaporation Model and assesses the role of double-parton scattering at the LHC.

Findings

Data suggests dominant double-parton scattering contribution.

First calculation of one-loop QCD corrections in CEM.

Effective cross section smaller than for jet observables.

Abstract

We briefly review recent results which we have obtained in the study of J/psi+Z production at the LHC. Considering our NLO computation in the Colour Evaporation Model (CEM) as an upper theory limit for the single-parton-scattering contributions, we claim that the existing data set from ATLAS points at a dominant double-parton-scattering contribution with an effective cross section smaller than that for jet-related observables. As a side product of our analysis, we have computed, for the first time, the one-loop QCD corrections to the J/psi P_T-differential cross section in the CEM.