Fermion helicity flip by parity violating torsion

The helicity flip of a spin-1/2 Dirac fermion interacting with a torsion-field endowed with a pseudo-tensorial extension is analysed. Taking the torsion to be represented by a Kalb–Ramond field, we show that there is a finite amplitude for helicity flip for massive fermions. The lowest order contribution which turns out to be proportional to the pseudo-tensor term, implies a new physical understanding of the phenomenon of helicity flip.