Perspectives of thermal photon measurements in heavy ion collisions at NICA

Abstract

The main goal of the future NICA-MPD experiment is studying the dense baryonic matter produced in heavy-ion collisions in the energy range 4-11 GeV and searching for signs of the phase transition between hadronic matter and deconfined quark-gluon plasma. Measurements of soft thermal photon yields and collective flow can significantly extend the physics program of the MPD experiment, allowing one to probe the temperature and the level of thermalizaion of the medium created in heavy ion collisions at NICA energies. The optimal method to measure soft photons is to register photon conversions in the material of the tracking system. In this contribution, recent RHIC and LHC results on thermal photon spectra and flow will be presented. Motivation and feasibility of thermal photon measurements with the conversion method in the projected MPD setup will be discussed.