XYZ spectroscopy at electron-hadron facilities: Exclusive processes

TL;DR

This paper estimates the cross sections for observing XYZ exotic hadrons in photon-induced reactions at upcoming electron-hadron facilities, highlighting the potential for new discoveries and insights into their structure.

Contribution

It provides the first estimates of exclusive production cross sections for XYZ states in photon-induced processes based on existing data and phenomenology.

Findings

Cross sections of a few nanobarns for Zc(3900)+ near threshold.

Cross sections of tens of nanobarns for X(3872).

Predictions are within reach of upcoming facilities.

Abstract

The next generation of electron-hadron facilities has the potential for significantly improving our understanding of exotic hadrons. The XYZ states have not been seen in photon-induced reactions so far. Their observation in such processes would provide an independent confirmation of their existence and offer new insights into their internal structure. Based on the known experimental data and the well-established quarkonium and Regge phenomenology, we give estimates for the exclusive cross sections of several XYZ states. For energies near threshold we expect cross sections of few nanobarns for the Zc(3900)+ and upwards of tens of nanobarn for the X(3872), which are well within reach of new facilities.