Observation of a Narrow Meson Decaying to Ds+pi0 at a Mass of 2.32 GeV/c^2

TL;DR

This paper reports the discovery of a narrow meson state at 2.32 GeV/c^2 decaying to Ds+ pi0, observed in e+e- collisions, with properties suggesting it is a JP=0+ state and indicating isospin violation.

Contribution

First observation of a narrow Ds+ pi0 meson state near 2.32 GeV/c^2 with quantum number analysis suggesting JP=0+ and isospin violation.

Findings

Observed a narrow state at 2.32 GeV/c^2 in Ds+ pi0 invariant mass

State has a width consistent with experimental resolution

Quantum number analysis suggests JP=0+

Abstract

We have observed a narrow state near 2.32 GeV/c^2 in the inclusive Ds+ pi0 invariant mass distributionfrom 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 JP=0+ assignment. The data sample corresponds to an integrated luminosity of 91 fb-1 recorded by the BABAR detector at the PEP2 asymmetric-energy e+e- storage ring.