Probing rescattering effect in heavy-ion collisions with ALICE at the LHC

Hadronic resonances are short-lived particles which decay via strong interaction. During the hadron gas phase that follows the hadronisation of the medium created in heavyion collisions and spans from the chemical to the kinetic freeze-out, resonances having lifetimes comparable to the duration of the hadronic phase take part in two processes, called regeneration and rescattering. These effects lead to the modification of their yields, which depend on their lifetime, the hadronic cross section of their decay products, and the hadronic phase lifetime. Rescatterings with other hadrons in the medium alter the momentum of the resonance decay products and prevent the reconstruction of the resonance with an invariant-mass analysis. In turn, pseudoelastic scattering could also regenerate the resonance leading to an enhancement of their yields. Both these competing effects determine the final yield of the resonances at kinetic freeze out. These processes can be studied from the ratios of the yields of resonances to stable particles having same quark content, as a function of system size and comparing with model predictions with and without hadronic interactions.