Spin precession and neutrino helicity flip under the influence of a gravitational plane wave

We recently studied spin precession in various stationary and axisymmetric spacetimes and applied it to the case of neutrinos propagating in those spacetimes. In this paper, the study of spin precession is extended to the case of a spinning particle propagating within the spacetime of a time-dependent gravitational plane wave. First, the angular velocity of spin precession of a particle propagating in a geodesic along an arbitrary direction relative to the gravitational wave is derived. Our general result is then used to derive the helicity flip probability for neutrinos freely propagating along such an arbitrary direction within the gravitational wave.