Observation of a Narrow Meson Decaying to Ds pi0 gamma at a Mass of 2.458 GeV/c^2

Abstract

A narrow state, which we label DsJ(2458)+, with mass 2458.0 +/- 1.0(stat.) +/- 1.0(syst.) MeV/c^2, is observed in the inclusive Ds+ pi0 \gamma$ mass distribution in 91 fb-1 of e^+e^- annihilation data recorded by the BABAR detector at the PEP-II asymmetric-energy e^+e^- storage ring. The observed width is consistent with the experimental resolution. The data favor decay through Ds*(2112)+ pi0 rather than through DsJ*(2317)+ gamma. An analysis of Ds+ pi0 data accounting for the influence of the DsJ(2458)+ produces a DsJ*(2317)+ mass of 2317.3 +/- 0.4(stat.) +/- 0.8(syst.) MeV/c^2.