An Experimental Review of Charmonium

TL;DR

This paper reviews recent experimental findings in the charmonium system, highlighting new measurements and observations that enhance understanding of the strong force and quark interactions.

Contribution

It provides a comprehensive summary of recent experimental results in charmonium, including new measurements of transition rates, masses, and decay modes, advancing the field's knowledge.

Findings

New measurements of radiative transition rates

Observation of J/ψ decays to three photons

Precise mass measurement of h_c(1P)

Abstract

This review briefly outlines recent experimental results from the charmonium system. These include new measurements of the M1 radiative transition rates $B(\psi(1S,2S)\to\gamma\eta_c(1S))$; new insights into the mass of the $\eta_c(1S)$; the observation of $J/\psi(1S)$ decays to three photons; new measurements of the two-photon widths of the $\chi_{cJ}(1P)$; the observation of radiative decays of the $\chi_{cj}(1P)$ to light quarks; a precise measurement of the $h_c(1P)$ mass; and an update on properties of the $\eta_c(2S)$. Each result adds piecemeal to our understanding of the strong force.