Nuclear Parton Distributions - a DGLAP Analysis

Abstract

Nuclear parton distributions $f_A(x,Q^2)$ are studied within a framework of the DGLAP evolution. Measurements of $F_2^A/F_2^D$ in deep inelastic $lA$ collisions, and Drell--Yan dilepton cross sections measured in $pA$ collisions are used as constraints. Also conservation of momentum and baryon number is required. It is shown that the calculated $Q^2$ evolution of $F_2^{\mathrm{Sn}}/F_2^{\mathrm{C}}$ agrees very well with the recent NMC data, and that the ratios $R_f^A=f_A/f$ are only moderately sensitive to the choice of a specific modern set of free parton distributions. For general use, we offer a numerical parametrization of $R_f^A(x,Q^2)$ for all parton flavours $f$ in $A>2$, and at $10^{-6}\le x\le 1$ and $2.25{\mathrm{GeV}}^2\le Q^2\le 10^4{\mathrm{GeV}}^2$.

Comments: Talk in Quark Matter '99, 5 pages, includes 3 eps-figures