Extracting femtoscopic radii in the presence of significant additional correlation sources

Abstract: The Large Hadron Collider has provided large amounts of data on collisions of small systems, such as proton-proton and proton-lead at unprecedented collision energies. Their space-time size and structure can be inferred from the measurement of the femtoscopic correlations for pairs of identical particles. The analysis is complicated by the presence of significant additional sources of two-particle correlations, which influence the correlation function in the region of the femtoscopic effect. In this work we use p-Pb events generated in a model that includes such additional correlation sources to characterize them and propose a robust method of taking them into account in the extraction of the femtoscopic information.