Observation of a narrow meson decaying to Ds + π0 γ at a mass of 2.458 GeV/c2

A narrow state, which we label DsJ(2458)+, with a mass 2458.0 ± 1.0 (stat) ± 1.0 (syst) MeV/c2, is observed in the inclusive Ds + π0γ mass distribution in 91 fb-1 of e+e- annihilation data recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e +e- storage ring. The observed width is consistent with the experimental resolution. The data favor decay through D* s(2112) + π0 rather than through D*sJ(2317) + γ. An analysis of D s + π0 data accounting for the influence of the DsJ(2458)+ produces a D*sJ(2317) + mass of 2317.3±0.4 (stat)±0.8 (syst) MeV/c 2. © 2004 The American Physical Society.