Production of $f^0$ mesons in $4.5-\frac{\mathrm{GeV}}{c} {\pi }^{-}p$ interactions

An optical spark chamber and neutron time-of-flight spectrometer experiment studied the reaction ${\pi }^{-}p\to {\pi }^{+}{\pi }^{-}n$ at incident pion momentum of $4.5 \frac{\mathrm{GeV}}{c}$ in the mass region of the $f^0$ meson. Analysis of the data shows no evidence for anomalous structure in the $f^0$ mass spectrum. The two-pion differential cross section in the $f^0$ region is consistent with Wolf's one-pion-exchange model for momentum transfers (squared) $-t\lesssim 0.7 {\left(\frac{\mathrm{GeV}}{c)}\right)}^2$. The differential cross section is larger than that predicted at high momentum transfer, and may be attributed to natural-parity-exchange contributions as evidenced in the $f^0$ decay distribution.