Neutron pairing with medium polarization beyond the Landau approximation

We reexamine the longstanding problem of the superfluid transition temperature Tc in dilute neutron matter. It is well known that Tc is strongly affected by medium polarization effects (screening), which modify the pairing interaction in the medium. We study these effects within the random-phase approximation (RPA). It turns out that the widely used Landau approximation is sufficient only at densities below about 0.002fm-3. At higher densities, the full RPA leads to stronger screening than the Landau approximation.