(770)⁰andf₀(980) production in Au+Au and pp collisions at

Preliminary results on ρ(770) 0 and f 0 (980) production at mid-rapidity using the mixed-event technique are presented. The ρ 0 and f 0 measurements via their hadronic decay channel in minimum bias pp and peripheral Au+Au collisions at were performed using the STAR detector at RHIC. This is the first direct measurement of ρ 0 (770) → π + π − and f 0 (980) → π + π − in heavy-ion collisions. The ρ 0 mass is transverse momentum dependent and significantly shifted in minimum bias pp and peripheral Au+Au interactions. The modifications of masses, widths and line shapes of short-lived resonances due to phase space and dynamical effects are discussed. The ρ 0 /π − and the f 0 /π − ratios are compared to measurements in pp and e + e − interactions at various energies.