The complex energies of the three-body resonances for one infinitely heavy particle and two non-interacting light particles are the sum of the two contributing two-body complex resonance energies. The bound state of a Borromean system originates from a resonance when the third interaction is introduced, a finite mass is allowed and proper angular momentum coupling is included. The relative impo...

Energy-dependent N-N separable potentials proposed recently by Garcilazo are examined in trinucleon systems. For-the special energydependence of the two-body potentials chosen there the Faddeev equations are well defined, unique, and preserve three-body unitarity. It is found that Garcilazo potentials overbind the triton by more than 14 MeV. A modified Garcilazo potential is proposed, which tak...

We investigate the possibility for a quark-antiquark pair to form a bound state at temperatures higher than the critical one (T > Tc), thus after deconfinement. Our main goal is to find analytical criteria constraining the existence of such mesons. Our formalism relies on a Schrödinger equation for which we study the physical consequences of using both the free energy and the internal energy as...

The R-matrix method is used to study electron collisions with the BeH molecular ion. The diatomic version of the UK Molecular R-matrix codes is used and a configuration-interaction calculation is first performed for the BeH target to obtain its potential energy curves for 19 lowest singlet and triplet states. Scattering calculations are then done to yield excitation and rotational excitation cr...