Photoproduction of Mesons off Light Nuclei -- the Search for \eta -Mesic Nuclei

TL;DR

This study investigates ta meson photoproduction off light nuclei to search for ta-mesic nuclei, revealing strong threshold effects and first-time observations that suggest possible bound states.

Contribution

It provides new experimental evidence of ta-mesic nuclei through threshold behavior analysis in light nuclei photoproduction.

Findings

Strong threshold enhancement in ta photoproduction off 3He

First observation of coherent ta photoproduction off 7Li

Preliminary results indicating potential ta-mesic states

Abstract

Photoproduction of \eta mesons off light nuclei (d, 3He, 7Li) has been measured at the tagged photon beam of the Mainz MAMI accelerator with the combined Crystal Ball/TAPS detection system. Special attention was given to the threshold behavior of the reactions in view of possible indications for the formation of (quasi-) bound \eta -nucleus states, so-called \eta -mesic nuclei. A very strong threshold enhancement of coherent \eta photoproduction off 3He was found and coherent \eta photoproduction off 7Li was observed for the first time. Preliminary results will be discussed.