  Elastic proton scattering on ${}^{3}{H}$ nucleus is studied inbetween p-%
${}^{3}{H}$ and n-${}^{3}{He}$ thresholds, in the energy region where
$\alpha$-particles first excited state is inbeded in the continuum. For this
aim Faddeev-Yakubovski equations are solved in configuration space, fully
considering effects due to the isospin breaking as well as rigorously treating
Coulomb interaction. Different realistic nuclear Hamiltonians are tested,
elucidating open problems in nuclear interaction description.
