$\ddot{I}(770{)}^0$ and $f_0(980)$ Production in Au+Au and pp Collisions at $\sqrt{s_{NN}}$ = 200 GeV

Abstract

Preliminary results on $\ddot{I}(770{)}^0$ and $f_0(980)$ production at mid-rapidity using the mixed-event technique are presented. The $\ddot{I}{}^0$ and $f_0$ measurements via their hadronic decay channel in minimum bias pp and peripheral Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV were performed using the STAR detector at RHIC. This is the first direct measurement of $\ddot{I}{}^0(770)\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}$ and $f_0(980)\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}$ in heavy-ion collisions. The $\ddot{I}{}^0$ 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 $\ddot{I}{}^0/\ddot{I}{€}^{-}$ and the $f_0/\ddot{I}{€}^{-}$ ratios are compared to measurements in pp and e${}^{+}$e${}^{-}$ interactions at various energies.

6 pages, 4 figures, proceedings of Strange Quarks in Matter (SQM2003), Atlantic Beach, USA, to be published in J. Phys. G