Experimental overview of charmonium spectroscopy

TL;DR

This paper reviews recent experimental findings on charmonium spectroscopy, highlighting precise measurements below the open-charm threshold and new state identifications above it from multiple experiments.

Contribution

It provides a comprehensive overview of recent experimental results, including high-precision measurements and the identification of new charmonium states.

Findings

Precise measurements of eta_c, eta_c(2S), h_c masses and widths.

Identification of chi_{c2}(2P) in gamma gamma processes.

Evidence of X(3823) consistent with psi_2(1^{2}D_2) state.

Abstract

In this talk, I review the recent experimental results on charmonium spectroscopy from BESIII, Belle, BaBar and CLEOc. Below the open-charm threshold, the masses and widths of spin-singlet states eta_c, eta_c(2S), h_c are measured with high precision. Above the threshold, chi_{c2}(2P) is identified in the process gamma gamma -> chi_{c2}(2P) -> gamma D bar{D}; Evidence of X(3823) is found in the M(chi_{c1} gamma) invariant-mass distribution for B -> gamma chi_{c1} K decays, the measured properties are consistent with the missing psi_2(1^{2}D_2) state.