Nuclear $p_{\perp }$-broadening of Drell-Yan and quarkonium production from SPS to LHC

Abstract

The nuclear $p_{\perp }$-broadening of Drell-Yan and quarkonium ($J/\psi$, ${\rm Y}$) production in $\pi$A and pA collisions is investigated. The world data follow a simple scaling from SPS to LHC energies, once the process-dependent color factors are properly taken into account, which allows for the extraction of the transport coefficient in cold nuclear matter. We find that $\hat{q}(x)\propto x^{-\alpha }$ with $\alpha =0.25$-$0.30$. The magnitude of the transport coefficient at $x=10^{-2}$ is ${\hat{q}}_0=0.051$ GeV${}^2$/fm and ${\hat{q}}_0=0.075$ GeV${}^2$/fm, whether $Q\bar{Q}$ pairs are assumed to be produced as color octet or color singlet states, respectively. The relation between nuclear broadening data and the (CT14) gluon density is also investigated.

Comments: 22 pages, 5 figures