Open charm contributions to the E1 transitions of $\psi(3686)$ and $\psi(3770)\to \gamma\chi_{cJ}$

TL;DR

This paper investigates the E1 radiative transitions of $\psi(3686)$ and $\psi(3770)$ to $\chi_{cJ}$ states using a non-relativistic effective field theory that includes open charm effects, revealing their crucial role in matching experimental results.

Contribution

It introduces a systematic way to include open charm effects and $S$-$D$ mixing in the analysis of charmonium E1 transitions within a non-relativistic effective field theory framework.

Findings

Open charm effects are essential for accurate transition rate predictions.

Discrepancies between leading order calculations and experimental data are resolved.

The framework allows self-consistent inclusion of $S$-$D$ mixing.

Abstract

The E1 transitions of $\psi(3686)$ and $\psi(3770)\to \gamma\chi_{cJ}$ are investigated in a non-relativistic effective field theory (NREFT) where the open charm effects are included systematically as the leading corrections. It also allows a self-consistent inclusion of the $S$-$D$ mixing in the same framework. We are able to show that the open charm contributions are essential for understanding the significant discrepancies between the non-relativistic leading order calculations and the experimental data.