Discovery of a Narrow Resonance ine+e−Annihilation

Abstract

We have observed a very sharp peak in the cross section for $e^{+}{e}^{-}\to \mathrm{hadrons}, e^{+}{e}^{-}$, and possibly ${\mu }^{+}{\mu }^{-}$ at a center-of-mass energy of 3.105±0.003 GeV. The upper limit to the full width at half-maximum is 1.3 MeV.