Centrality Dependence of and ϕ(1020) Production at LHC**Supported by Council of Scientific and Industrial Research, New Delhi for This Work

Abstract

We study the centrality dependence of the mid-rapidity yields and transverse momentum distributions of and resonances produced in Pb + Pb collisions at . The mid-rapidity density and the shape of the transverse momentum spectra are well reproduced by an earlier proposed Unified Statistical Thermal Freeze-out Model (USTFM), which incorporates the effects of both longitudinal as well as transverse hydrodynamic flow. The freeze-out properties in terms of kinetic freeze-out temperature and transverse flow velocity parameter are extracted from the model fits to the transverse momentum data provided by the ALICE experiment at the LHC. The kinetic freeze-out temperature is found to increase with decreasing event centrality while the transverse flow velocity parameter shows a mild decrease on moving towards peripheral collisions. Moreover the centrality dependence of the mid-rapidity system size at freeze-out has also been studied in terms of transverse radius parameter.