Acceleration of a polarized neutron by internal weak nuclear forces

It is proven that a polarized neutron gets accelerated by internal nuclear forces along the coherent rotation of its spin. The net force upon the neutron arises from the weak nuclear interactions between its quarks. It is the result of the simultaneous breaking of parity symmetry by the chiral interactions between the neutron's quarks, and of time-reversal symmetry along the inversion of their spins. The variation of the neutron's kinetic momentum is accompanied with the transfer of an equivalent momentum to the fields of the Z and W bosons that mediate the interactions, in the opposite direction. The effect is linear in Fermi's constant. Using the simplest hadron models, an upper bound of the order of meters per second is estimated for the velocity variation of the polarized neutron along the spin-flip process.