Recent Charmonium Results from BES (Talk Presented at DPF99)

TL;DR

This paper summarizes recent BES experimental results on charmonium states, including decay branching ratios, mass measurements, and insights into the rho-pi puzzle, advancing understanding of charmonium spectroscopy.

Contribution

It provides new experimental measurements of branching ratios and masses of charmonium states, contributing valuable data to the field.

Findings

Measured B(J/psi -> l^+ l^-) = 5.87 +/- 0.04 +/- 0.09

Mass of chi_c0 = 3414.1 +/- 0.6 +/- 0.8 MeV

Mass of eta_c = 2975.8 +/- 3.9 +/- 1.2 MeV

Abstract

Recent results obtained from the BES psi(2S) data are summarized, including the measurement of the branching ratio of the J/psi to leptons, B(J/psi -> l^+ l^-) = 5.87 +/- 0.04 +/- 0.09, many psi(2S) and chi_c branching ratios, information on the rho-pi puzzle, and measurements of the mass of the chi_c0, m(chi_c0) = 3414.1 +/- 0.6 +/- 0.8 MeV, and the eta_c, m(eta_c) = 2975.8 +/- 3.9 +/- 1.2 MeV.