Evidence for the Existence of a New Meson in the 955-MeV Mass Region

We report evidence for the existence of a new meson, which we call the $M(953)$, with mass 953 ±{} 2 MeV and width 10 MeV, produced in the final state K^-p→pK^-M⁰ at incident momenta 3.9 and 4.6GeV/c. These results are based primarily on a signal of 68 ±{} 12 events in the decay mode M→π⁺π^-γ where the ππ system does not show a ρ⁰ signal, in sharp distinction to the ρ⁰γ decay mode of the η^'(958).