Speaker
Description
Recent theoretical studies of eta nuclear quasi-bound states in few- and many-body
systems are reviewed [1,2,3,4].
Underlying energy-dependent eta-N interactions are derived from coupled-channel models
that incorporate the N*(1535) resonance. The role of self-consistent treatment of the
strong energy dependence of the subthreshold eta-N amplitudes is discussed.
Binding energies and widths of eta-nuclear states were calculated within several
eta-N interaction models. No etaNN bound state was found. The onset of etaNNN binding
occurs for the etaN scattering length Rea_{etaN} close to 1 fm, binding eta-4He requires
Rea_{etaN} larger than 0.7 fm. Bound states of eta in 12C are unlikely in models with
Rea_{etaN} less than 0.5 fm, while Rea_{etaN} about 0.9 fm is required to reproduce the
etaN bound-state candidate in 25Mg from the COSY-GEM experiment [5].
[1] E. Friedman, A. Gal, J. Mares, Phys. Lett. B 725 (2013) 334.
[2] A. Cieply, E. Friedman, A. Gal, J. Mares, Nucl. Phys. A 925 (2014) 126.
[3] N. Barnea, E. Friedman, A. Gal, Phys. Lett. B 747 (2015) 345.
[4] N. Barnea, B. Bazak, E. Friedman, A. Gal, Phys. Lett. B 771 (2017) 297.
[5] A. Budzanowski et al (COSY-GEM Collaboration), Phys. Rev. C 79 (2009) 012201 (R).
