Observation of a Narrow Meson State Decaying to ${D}_{s}^{+}{\ensuremath{\pi}}^{0}$ at a Mass of $2.32\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/{c}^{2}$

Observation of a Narrow Meson State Decaying to $D_{s}^{+} π^{0}$ at a Mass of $2.32 G e V / c^{2}$

B. Aubert et al. (BABAR Collaboration)

Phys. Rev. Lett. 90, 242001 – Published 17 June 2003

Abstract

We have observed a narrow state near $2.32 G e V / c^{2}$ in the inclusive $D_{s}^{+} π^{0}$ invariant mass distribution from $e^{+} e^{-}$ annihilation data at energies near 10.6 GeV. The observed width is consistent with the experimental resolution. The small intrinsic width and the quantum numbers of the final state indicate that the decay violates isospin conservation. The state has natural spin-parity and the low mass suggests a $J^{P} = 0^{+}$ assignment. The data sample corresponds to an integrated luminosity of $91 {f b}^{- 1}$ recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy $e^{+} e^{-}$ storage ring.