Soft photon study at NICA’s facilities

Abstract For over three decades there has been no comprehensive understanding of the mechanism of soft photon (energy smaller than 50 MeV) formation. Experimental data indicate an excess of their yield in hadron and nuclear interactions in comparison with calculations performed theoretically. In JINR, in connection with the building of a new accelerator complex NICA, it has become possible to carry out such studies in pp, pA and AA interactions at energies up to 25 A GeV. We prepared the extensive physical program for soft photons that covers the wide region of investigations in high energy physics. To carry out this program our group develops the conception of an electromagnetic calorimeter on type “shashlik” based on gadolinium-gallium garnet (GaGG) crystals, which have a significantly lower threshold for the registration of photons. The first tests of electromagnetic calorimeters manufactured at the Joint Institute for Nuclear Research on the basis of the GaGG crystals and a composite of tungsten and copper are reported.