Dissipation and Fragmentation of Low-q Scattered Partons in Au-au Collisions at Rhic

Two-particle correlations and event-wise fluctuations in transverse momentum p t are reported for Au-Au collisions at √ s N N = 62 and 200 GeV on pseudorapidity η and azimuth φ. Distributions of all pairs of particles (no leading trigger particle) reveal jet-like correlations, or peaks at pair-wise opening angles of order 1 radian or less. The width of this same-side correlation peak increases dramatically on pseudorapidity and decreases on azimuth for increasing collision centrality. Evolution of the same-side peak with centrality suggests dissipation of low-Q 2 partons via strong coupling to an expanding bulk medium. p t correlations, which provide access to temperature and/or velocity distributions in the colliding system, are also presented.