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

TL;DR

This paper reports the first observation of the $ ext{psi}(4415)$ resonance decaying into $D ar D_2^*(2460)$ using initial-state radiation, providing new insights into its decay mechanisms and cross section measurements.

Contribution

First observation of $ ext{psi}(4415)$ decay into $D ar D_2^*(2460)$ via initial-state radiation, with quantitative analysis of decay channels and cross sections.

Findings

$ ext{psi}(4415)$ decay dominated by $D ar D_2^*(2460)$ channel

Measured upper limit on non-resonant decay branching ratio

Cross section of $ ext{psi}(4415)$ in the studied energy range

Abstract

We report the first observation of the $\psi(4415)$ resonance in the reaction $\e^+e^-\to D^0 D^-\pi^+$ 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 $\psi(4415)$ decay we conclude that the $\psi(4415)\to D^0 D^-\pi^+$ decay is dominated by $\psi(4415)\to D \bar D{}^{*}_2(2460)$. We obtain $\mathcal{B}(\psi(4415)\to D^0 D^-\pi^+_{\mathrm {non-resonant}})/\mathcal{B}(\psi(4415)\to D \bar D{}^{*}_2(2460)\to D^0 D^-\pi^+)<0.22$ at 90% C.L. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of 673 $\mathrm{fb}^{-1}$.