Estimation of pion-emitting source in symmetric and asymmetric collisions using the UrQMD model

The femtoscopy technique allows one to measure spatial and temporal characteristics of the particle-emitting source produced in high-energy collisions. In non-central ultrarelativistic heavy-ion collisions the emission source can be tilted in the reaction plane. In the current analysis, the orientation of freeze-out distributions with respect to the first-order event plane in symmetric (Au+Au) and asymmetric (Cu+Au) collisions at $$\sqrt {{s_{NN}}} = 200$$ GeV was studied using the UrQMD model to extract information about the emission source tilt. The effect of the initial geometry on the femtoscopic radii of small systems was measured at the same number of charged particles and transverse momentum was studied in d+Au and 3He+Au collisions at $$\sqrt {{s_{NN}}} = 200$$ GeV. The implications of the results are discussed