Possibility to study eta-mesic nuclei and photoproduction of slow eta-mesons at the GRAAL facility

Baskov, V. A.; Bocquet, J. P.; Kouznetsov, V.; Lleres, A.; L'vov, A. I.; Pavlyuchenko, L. N.; Polyanski, V. V.; Rebrevend, D.; Sokol, G. A.

Possibility to study eta-mesic nuclei and photoproduction of slow eta-mesons at the GRAAL facility

Authors

Description

A new experiment is proposed with the aim to study eta-mesic nuclei and low-energy interactions of eta with nuclei. Two decay modes of eta produced by a photon beam inside a nucleus will be observed, namely a collisional decay ηN \to πN inside the nucleus and the radiative decay η\to γγoutside. In addition, a collisional decay of stopped S_{11}(1535) resonance inside the nucleus, S_{11}(1535) N \to N N, will be studied. The experiment can be performed using the tagged photon beam at ESRF with the end-point energy 1000 MeV and the GRAAL detector which includes a high-resolution BGO calorimeter and a large acceptance lead-scintillator time-of-flight wall. Some results of simulation and estimates of yields are given.
20 pages, 19 figures