Measuring centrality with slow protons in proton-nucleus collisions at the AGS

Abstract

Experiment 910 has measured slow protons and deuterons from collisions of 18 GeV/c protons with Be, Cu, and Au targets at the BNL AGS. These correspond to the ``grey tracks'' first observed in emulsion experiments. We report on their momentum and angular distributions and investigate their use in measuring the centrality of a collision, as defined by the mean number of projectile-nucleon interactions. The relation between the measured Ngrey and the mean number of interactions, nu(Ngrey), is studied using several simple models, one newly proposed, as well as the RQMD event generator. RQMD is shown to reproduce the Ngrey distribution, and exhibits a dependence of Ngrey on centrality that is similar to the behavior of the simple models. We find a strong linear dependence of average Ngrey on nu, with a constant of proportionality that varies with target. For the Au target, we report a relative systematic error for extracting nu(Ngrey) that lies between 10% and 20% over all Ngrey.

24 pages, 19 figures, submitted for publication to Phys. Rev. C, Formatted with RevTex Replacement: Fix typos, improve display figures, twocolumn format

Cited by in corpus (12)

• Centrality dependence of particle production in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$= 5.02 TeV
• Centrality categorization for R_{p(d)+A} in high-energy collisions
• Inhomogeneous Shadowing Effects on J/ψProduction in dA Collisions
• Centrality dependence of $\psi$(2S) suppression in p-Pb collisions at $\sqrt{{\text{s}}_{\mathrm{NN}}}$ = 5.02 TeV
• Hard probes in heavy ion collisions at the LHC: PDFs, shadowing and $pA$ collisions
• Systematic Study of the Kaon to Pion Multiplicity Ratios in Heavy-Ion Collisions
• Semi-Inclusive Lambda and Kshort Production in p-Au Collisions at 17.5 GeV/c
• Antiproton Production in $p+A$ Collisions at AGS Energies
• Centrality dependence of the thermal excitation-energy deposition in 8-15 GeV/c hadron-Au reactions
• Effects of in-medium cross-sections and optical potential on thermal-source formation in p+197Au reactions at 6.2-14.6 GeV/c
• Experimental Efforts on Very High-Energy Cosmic Rays and their Interactions - Conference Summary
• Studies of Nucleon-Gold Collisions at 200 GeV per Nucleon Pair Using Tagged d+Au Interactions