From particle emission at accelerator facilities to axion properties in neutron stars: proton-pion femtoscopy at ALICE

by Marcel Lesch (TUM)

Thursday 13 Jun 2024, 09:30 → 11:00 Europe/Berlin

E18/ENE Seminar Room 3268 (TUM PH)

The composition of the innermost region of neutron stars is unknown, and the possible appearance of QCD axions has recently been proposed. The properties of these axions at finite baryonic density relate to the coupling of pions to many nucleons, which is accessible in pp collisions at the LHC. Here, the emission of multiple hadrons helps to mimic high densities due to their small production distances of a few femtometers (fm). This talk demonstrates these short distances with recent measurements of the particle-emitting source size using two-body femtoscopy of pπ pairs in pp collisions at √s = 13 TeV by ALICE. The resulting source size scaling against the transverse mass agrees with previous results for baryon-baryon and meson-meson pairs by ALICE, reinforcing the idea of a common emission source for all hadrons. Using three-body femtoscopy, we present the first measurement of ppπ correlations, unveiling effects beyond pairwise interactions. This offers a unique opportunity to investigate the axion and its impact on neutron stars.