Thermal photons from fluctuating initial conditions

Abstract

Event-by-event fluctuations of initial QCD-matter density produced in heavy-ion collisions at RHIC enhance the production of thermal photons significantly in the region $2\le p_T\le 4$ GeV/$c$ compared to a smooth initial-state averaged profile in the ideal hydrodynamic calculation. This enhancement is a an early time effect due to the presence of hotspots or over-dense regions in the fluctuating initial state. The effect of fluctuations is found to be stronger in peripheral than in central collisions.

Comments: 4 pages, 3 figures. Talk given at Quark Matter 2011, 22-28 May 2011, Annecy, France