Eur. Phys. J. C (2007) 49: 249-253
https://doi.org/10.1140/epjc/s10052-006-0089-2

Regular Article – Experimental Physics

Measurement of photons via conversion pairs in  =200 GeV Au+Au collisions with the PHENIX experiment at RHIC

Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794-3800, USA

^* e-mail: Torsten.Dahms@stonybrook.edu

Received: 4 August 2006
Published online: 27 October 2006

Abstract

Thermal photons can provide information on the temperature of the new state of matter created at RHIC. In the p_T region of 1–3 GeV/c thermal photons are expected to be the dominant direct photon source. Therefore, a possible excess compared to a pure decay photon signal due to a thermal photon contribution should be seen in the double ratio (γ/γ(π⁰))_Measured/(γ/γ(π⁰))_Simulated, if sufficient accuracy can be reached. We present a method to reconstruct direct photons by measuring e⁺e^--pairs from external photon conversions.