A look at the influence of the $J/\psi$ transverse momentum on shadowing

Abstract

Stringent physical constraints relate the $J/\psi$ produced at a given transverse momentum $p_T$ to the Bjorken-$x$ of the initial gluons. We present a new approach which takes them into account in order to explicitely investigate the $p_T$-dependence of the shadowing effect on the $J/\psi$ production. Using the $J/\psi$ rapidity and $p_T$ spectra extracted from $\sqrt{s}=200\mathrm{GeV}$ p + p data from PHENIX, we build a Glauber Monte-Carlo code which includes shadowing in two alternative ways: multiple scattering corrections or $Q^2$ evolution of parton densities. We present our results in d + Au collisions at the same energy, notably providing the first prediction of the $J/\psi$ nuclear modification factor as a function of $p_T$, and compare them to the available data by adding some nuclear absorption effect.

Comments: Proceedings prepared for the HLPW08 conference (Three days of strong interactions and astrophysics, March 2008, Belgium) and will be published in the "AIP conference proceedings series"