Recent Results From BESII

TL;DR

This paper reports recent experimental results from BESII, including observations of new particles and decay modes of J/psi and psi(2S), expanding understanding of charmonium states and decay processes.

Contribution

It provides new experimental observations of particles like Y(2175), η(2225), and X(1440), and reports on various decay modes of J/psi and psi(2S).

Findings

Observation of Y(2175) in J/psi decays

Detection of η(2225) in J/psi radiative decays

New decay modes of J/psi and psi(2S)

Abstract

We present recent results from the BES experiment on the observation of the Y(2175) in $J/\psi\to \phi f_0(980) \eta$, and $\eta(2225)$ in $J/\psi\to \gamma \phi \phi$, and X(1440) in $J/\psi$ hadronic decays, together with the new observation of $\psi(2S)$ radiative decays and hadronic decays into $n\ks\ldb+c.c., \ld\ldb\pi^0, \ld\ldb\eta$. The effort to search for $J/\psi$ decays into $\gamma\gamma$ and invisible decays are also reported.