Photon Detection in heavy-ion experiments

Abstract We present the measurements of multiplicity and pseudorapidity distributions of inclusive photons in proton-proton (pp) and heavy-ion (AA) collisions using the Photon Multiplicity Detector (PMD) employed at STAR and ALICE experiments. The working principle, design and features of PMD are discussed. The results are compared to different Monte Carlo (MC) predictions. The dependence of average photon multiplicity on centre-of-mass energy in pp collisions is discussed. The limiting fragmentation scenario for inclusive photon production in both pp and AA collisions are also reported.