Single-quark electromagnetic form factors of charmonium up to $J=2$

TL;DR

This paper computes electromagnetic form factors of various charmonium states using a relativized quark model, compares with other methods, and predicts form factors for states lacking direct data.

Contribution

It provides a comprehensive calculation of charmonium form factors with comparison to lattice QCD, DSE, and BLFQ, and offers new predictions for several states.

Findings

Most results agree with other approaches.

Reference frame dependence estimated as error.

Predictions made for unmeasured states.

Abstract

We calculate the single-quark electromagnetic form factors of a broad subset of charmonium, including $\eta_c(1S)$, $\eta_c(2S)$, $\chi_{c0}(1P)$, $\chi_{c0}(2P)$, $J/\psi(1S)$, $J/\psi(2S)$, $\chi_{c1}(1P)$, $\chi_{c1}(2P)$, $h_c(1P)$, $h_c(2P)$, $\chi_{c2}(1P)$ and $\chi_{c2}(2P)$, via a relativized quark model. The reference frame dependence of the results is estimated as the computational error. We compare our results with those of the lattice quantum chromodynamics (LQCD), the Dyson-Schwinger equation (DSE) and the basis light front quantization (BLFQ) approaches where available and we find that most of our results agree with the other results. We also predict the single-quark electromagnetic form factors of $\chi_{c0}(2P)$, $\chi_{c1}(2P)$, $h_c(1P)$, $h_c(2P)$, $\chi_{c2}(1P)$ and $\chi_{c2}(2P)$, where no direct comparisons are available.