Proton-3He elastic scattering at low energies and the “Ay Puzzle”

The Kohn variational principle and the hyperspherical harmonic technique are applied to study p − 3He elastic scattering at low energies. Preliminary results obtained using several interaction models are reported. The calculations are compared to a recent phase shift analysis performed at the Triangle University Nuclear Laboratory and to the available experimental data. Using a three-nucleon interaction derived from chiral perturbation theory at N2LO, we have found a noticeable reduction of the discrepancy observed for the Ay observable.