Accessing the deuteron source with pion-deuteron femtoscopy in Pb-Pb collisions at (Formula Presented)

Abstract

Femtoscopy of nonidentical particle pairs has been instrumental for precision measurements of both two particle sources and the final-state interactions in high-energy elementary and heavy-ion collisions. The majority of measurements assessing the source properties are based on identical particle pairs, providing direct access to the characteristics of the single-particle source. The work in this paper demonstrates, via femtoscopy mea surements of charged pion-deuteron pairs in Pb-Pb collisions at √ sNN = 5.02 TeV, the feasibility of accessing the characteristics of the single-particle femtoscopic source by using particle pairs with large mass differences such as pions and deuterons. The first experimental results of the measurement of deuteron source sizes in ultrarelativistic heavy-ion collisions are presented. The results show good agreement with the trend derived from other charged hadrons such as pions, kaons, and protons as a function of transverse mass, indicating similar source properties. © 2025 CERN, for the ALICE Collaboration