Search for psi(3770)\ra\rho\pi at the BESII detector at the Beijing Electron-Positron Collider

TL;DR

This study searches for the non-Dar{D} decay mode  ho\u03c0 at the BESII detector, finds no signal, and sets an upper limit on the cross section and branching fraction, supporting a charmonium mixing scheme.

Contribution

First measurement setting upper limits on  ho\u03c0 decay at 3.773 GeV, supporting charmonium state mixing models for the  ho\u03c0 puzzle.

Findings

No  ho\u03c0 signal observed.

Upper limit on cross section: <6.0 pb at 90% C.L.

Branching fraction range: (6.0^{-6}, 2.4^{-3}) at 90% C.L.

Abstract

Non-$D\bar{D}$ decay $\psppto \rhopi$ is searched for using a data sample of $(17.3\pm 0.5) pb^{-1}$ taken at the center-of-mass energy of 3.773 GeV by the BESII detector at the BEPC. No $\rhopi$ signal is observed, and the upper limit of the cross section is measured to be $\sigma(\EETO \rhopi)<6.0 pb$ at 90% C. L. Considering the interference between the continuum amplitude and the $\pspp$ resonance amplitude, the branching fraction of $\pspp$ decays to $\rho\pi$ is determined to be $\BR(\pspp\ra\rho\pi)\in(6.0\times10^{-6}, 2.4\times10^{-3})$ at 90% C. L. This is in agreement with the prediction of the $S$- and $D$-wave mixing scheme of the charmonium states for solving the ``$\rhopi$ puzzle'' between $\jpsi$ and $\psp$ decays.