First measurement of direct $f_0(980)$ photoproduction on the proton

Abstract

We report on the results of the first measurement of exclusive $f_0(980)$ meson photoproduction on protons for $E_{\hat{I}}^3=3.0-3.8$ GeV and $-t=0.4-1.0$ GeV${}^2$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the $\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ channel by performing a partial wave analysis of the reaction ${\hat{I}}^{3}p\to p\ddot{I}{€}^{+}\ddot{I}{€}^{-}$. Clear evidence of the $f_0(980)$ meson was found in the interference between $P$ and $S$ waves at $M_{\ddot{I}{€}^{+}\ddot{I}{€}^{-}}\sim 1$ GeV. The $S$-wave differential cross section integrated in the mass range of the $f_0(980)$ was found to be a factor of 50 smaller than the cross section for the $\ddot{I}$ meson. This is the first time the $f_0(980)$ meson has been measured in a photoproduction experiment.