A method based on transverse energy balance of jets for selection of direct photons and fragmentation photons in high energy pp collisions

Abstract

Direct photons are important probes in high energy collisions. They play an important role in determining the parton distribution function directly inside a proton as well as the nature of the matter formed in heavy ion collisions. However fragmentation photons play the role of prominent background in identifying the direct photons. In the present work we developed a new method based on the transverse energy balance of jets for enrichment of direct photon candidates in pp collisions. This method can reject 35% of the background photons (fragmentation) which can not be suppressed by isolation. Efficiency of detection of direct photon decrease by 10% in the method.