Nuclear p⊥-broadening of Drell-Yan and quarkonium production from SPS to LHC

The nuclear p⊥-broadening of Drell-Yan and quarkonium (J/ψ, Υ) production in πA 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 q̂x∝x−α\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \hat{q}(x)\propto {x}^{-\alpha } $$\end{document} with α = 0.25–0.30. The magnitude of the transport coefficient at x = 10−2 is q̂0=0.051GeV2/fm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\hat{q}}_0=0.051\;{\mathrm{GeV}}^2/\mathrm{fm} $$\end{document} and q̂0=0.075GeV2/fm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\hat{q}}_0=0.075\;{\mathrm{GeV}}^2/\mathrm{fm} $$\end{document}qˆ0 = 0.075 GeV2/fm, whether QQ¯\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ Q\overline{Q} $$\end{document} 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.