Studies of eta-mesic nuclei at the LPI electron synchrotron
  A brief review of searches for eta-mesic nuclei is presented with emphasis on photoreactions and results of a new experiment done at the LPI electron synchrotron are reported. Decay products of eta-mesic nuclei presumably formed by photons in a carbon target, namely correlated back-to-back (pi+ n) and (p n) pairs, have been studied with a two-arm time-of-flight setup. The obtained data show that apart from previously observed (pi+ n) pairs from one-nucleon annihilation of stopped etas (via eta N --> pi N) correlated (p n) pairs from two-nucleon absorption of eta in the nucleus (via eta NN --> NN) are also ejected with a comparable rate. The cross section of eta-mesic nuclei photoproduction off carbon was estimated from the obtained data to be less than 10 microbarn. 
V. A. Baskov (1), A. V. Koltsov (1), A. I. L'vov (1), A. I. Lebedev   (1), L. N. Pavlyuchenko (1), V. V. Polyanskiy (1), E. ...
nucl-ex