BES R measurements and $J/\psi$ decays

TL;DR

This paper reports on R measurements in the 2-5 GeV energy range by BESII and investigates the sigma particle in J/psi decays using a large BESI dataset, providing insights into particle interactions.

Contribution

It presents new R measurement results in the 2-5 GeV range and studies the sigma particle in J/psi decays with extensive data, advancing understanding of these phenomena.

Findings

R measurement results in 2-5 GeV region

Observation of sigma particle in J/psi decays

Analysis based on large BESI dataset

Abstract

R measurement results in 2--5 GeV region by BESII is reported in this talk. The study on $\sigma$ particle in $J/\psi \to \omega \pi^+ \pi^-$, based on $7.8 \times 10^6$ BESI $J/\psi$ data, is also reported.