The overview of the tasks for PWG1

• Grigory Feofilov (Saint-Petersburg State University)

Room: 241 In this report I am going to present the very first glimpse on studies started for the Global Observables at MPD/NICA at JINR. Topics of general interest will be mentioned with some emphasis on determination of centrality of the event. Some flashes from the SQM-2019 conference will be used as an illustration of the physic landscape. Motivations for our near steps are to be discussed.

Study of the energy distributions in FHCal and approaches for centrality measurements.

• Alexander Ivashkin (INR RAS, Moscow)

Room: 241 The dependences of energy distributions in FHCal modules on the polar angle and on the centrality were studied. They allow the construction of a few observables as transverse and longitudinal energies. The fit of angular distributions by the linear function on the event-by-event basis allows to extract the transverse gradient of the spectator energy in the calorimeter and also the energy carried by free spectators inside the beam hole. The clear correlations between the fit parameters are observed in full range of the collision centralities. Assuming, that the peripheral area of FHCal is occupied mainly by the non-spectator’s particles, their energy contribution to the full FHCal energy was subtracted. It makes possible to avoid the ambiguity in FHCal energy depositions for central and peripheral events. The developed approaches are used for the determination of the collision centrality with FHCal alone without application of TPC information on multiplicity.