Observation of $ψ(4415)\to D \bar D{}^{*}_2(2460)$ decay using initial-state radiation

Abstract

We report the first observation of the $ψ(4415)$ resonance in the reaction $\e^+e^-\to D^0 D^-π^+$ and a measurement of its cross section in the center-of-mass energy range $4.0\mathrm{GeV}$ to $5.0\mathrm{GeV}$ with initial state radiation. From a study of resonant structure in $ψ(4415)$ decay we conclude that the $ψ(4415)\to D^0 D^-π^+$ decay is dominated by $ψ(4415)\to D \bar D{}^{*}_2(2460)$. We obtain $\mathcal{B}(ψ(4415)\to D^0 D^-π^+_{\mathrm {non-resonant}})/\mathcal{B}(ψ(4415)\to D \bar D{}^{*}_2(2460)\to D^0 D^-π^+)<0.22$ at 90% C.L. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of 673 $\mathrm{fb}^{-1}$.