Autocorrelations from the scale dependence of transverse-momentum fluctuations in Hijing-simulated Au-Au collisions at $\sqrt{s_{NN}} = $ 200 GeV

Abstract

We present measurements of the scale (bin-size) dependence of event-wise mean transverse momentum $<p_{t}>$ fluctuations for Au-Au collisions at $\sqrt{s_{NN}} = 200$ GeV simulated with the Hijing-1.37 Monte Carlo. We invert those scale distributions to obtain autocorrelation distributions on pseudorapidity $\eta$ and azimuth $\phi$ difference variables $(\eta_\Delta,\phi_\Delta)$. The autocorrelations have a simple structure dominated by a same-side (on azimuth) peak with similar widths on the two difference variables. With jet quenching imposed, the same-side peak widths increase slightly in both directions, and the amplitude is substantially reduced. The same-side peaks are attributed to minijets, observed in this study as local {\em velocity} correlations of charged particles with $p_t < $ 2 GeV/c.