Abstract:

In collisions of relativistic nuclei, in addition to hot and dense matter formed in the overlap zone of colliding nuclei, relatively cold spectator matter is formed. Its properties have been studied in detail in the processes of fragmentation of nuclei with energies from 600 to 10 GeV/nucleon, but little is known about spectator fragments from nuclear collisions at colliders. Spectator fragments fly forward at small angles to the beam and therefore it is difficult to separate them from the beam nuclei. This report is devoted to the properties of spectator matter in collisions of ultrarelativistic nuclei at NICA, SPS and LHC energies. Particular attention is paid to the yields of spectator nucleons in ultracentral collisions of ultrarelativistic nuclei and the effect of the neutron skin parameters as well as the deformation of the colliding nuclei on them. The modelling results on the formation of spectator fragments in collisions of ¹⁶O nuclei at the LHC considering their cluster structure are also presented.