Shadowing Effects on the Nuclear Suppression Factor, R_dAu, in d+Au Interactions

Abstract

We explore how nuclear modifications to the nucleon parton distributions affect production of high transverse momentum hadrons in deuteron-nucleus collisions. We calculate the charged hadron spectra to leading order using standard fragmentation functions and shadowing parameterizations. We obtain the d+Au to pp ratio both in minimum bias collisions and as a function of centrality. The minimum bias results agree reasonably well with the BRAHMS data while the calculated centrality dependence underestimates the data and is a stronger function of p_T than the data indicate.

Figures (3)

• Figure 1: $R_{\rm dAu}$ for charged pions (dashed) and kaons (dot-dashed) as well as protons and antiprotons (dotted) and the sum over all charged hadrons (solid) for deuteron-gold collisions at $\sqrt{S_{NN}} = 200$ GeV as a function of $p_T$. The results for homogeneous shadowing with the EKS98 parameterization are compared to the minimum bias BRAHMS data brahmsdau in the following $\eta$ bins: (a) $|\eta| \leq 0.2$; (b) $\eta = 1$; (c) $\eta = 2.2$ and (d) $\eta = 3.2$.
• Figure 2: $R_{\rm dAu}$ for charged pions (dashed) and kaons (dot-dashed) as well as protons and antiprotons (dotted) and the sum over all charged hadrons (solid) for deuteron-gold collisions at $\sqrt{S_{NN}} = 200$ GeV as a function of $p_T$. The results for homogeneous shadowing with the FGS1 parameterization are compared to the minimum bias BRAHMS data brahmsdau in the following $\eta$ bins: (a) $|\eta| \leq 0.2$; (b) $\eta = 1$; (c) $\eta = 2.2$ and (d) $\eta = 3.2$.
• Figure 3: $R_{\rm CP}$ for charged hadrons in deuteron-gold collisions at $\sqrt{S_{NN}} = 200$ GeV as a function of $p_T$. The results for $S_{{\rm FGS1},\rho}$ are compared to the BRAHMS data brahmsdau in the following $\eta$ bins: (a) $|\eta| \leq 0.2$; (b) $\eta = 1$; (c) $\eta = 2.2$ and (d) $\eta = 3.2$. The calculated ratios of the most central and semi-central to peripheral collisions are shown in the solid and dashed curves, respectively. The BRAHMS data are given by the open circles (most central) and diamonds (semi-central).