Probing the Quark Gluon Plasma with Direct Photon-Hadron Correlations
|Date/Time:||Tuesday, 17 May 2011 from 4:10 pm to 5:00 pm|
|Location:||Room 18 Physics Hall|
A hot dense medium is observed in heavy ion collisions at RHIC and direct photon-hadron correlations are considered a "golden channel" for studying this matter. Direct photons are predominately produced via the Compton scattering of a quark and gluon into a quark and photon. Since photons do not interact with the strongly coupled medium, they escape unmodified and can be used to approximate the initial energy of the opposing quark. The quark fragments into hadrons which are measured in the detectors. By integrating the yield of the hadrons on the "away-side" opposite from the trigger photon and knowing the initial parton energy, we can measure the quark fragmentation function in p+p collisions and the effective modifications in Au+Au collisions due to energy loss and medium response. However, this measurement is complicated by the large background from decay photons.
A statistical subtraction method and event-by-event techniques have been established at PHENIX for extracting the direct photon-hadron correlations. The latest results from these measurements will be presented.