Suppression pattern of neutral pions at high transverse momentum in Au+Au collisions at sqrt(s_NN) = 200 GeV and constraints on medium transport coefficients

TL;DR

This study measures neutral pion suppression at high transverse momentum in Au+Au collisions at 200 GeV, revealing a consistent suppression pattern that constrains medium transport properties and scales with the number of participants.

Contribution

It provides precise measurements of neutral pion suppression up to 20 GeV/c, constrains medium transport coefficients, and shows suppression scales with N_part^{2/3}.

Findings

Fivefold suppression of neutral pions at high p_T

Suppression remains constant between 5 and 20 GeV/c

Suppression increases with N_part^{2/3}

Abstract

For Au + Au collisions at 200 GeV we measure neutral pion production with good statistics for transverse momentum, p_T, up to 20 GeV/c. A fivefold suppression is found, which is essentially constant for 5 < p_T < 20 GeV/c. Experimental uncertainties are small enough to constrain any model-dependent parameterization for the transport coefficient of the medium, e.g. \mean(q^hat) in the parton quenching model. The spectral shape is similar for all collision classes, and the suppression does not saturate in Au+Au collisions; instead, it increases proportional to the number of participating nucleons, as N_part^2/3.