Electromagnetic Currents from Electroweak Fermion Level Crossing

Abstract

Spectral flow of chiral fermions in the background of electroweak sphalerons is studied. A fermion field configuration that interpolates between the sphaleron zero mode and the asymptotic fermion modes is proposed for the level crossing left handed fermion fields. It is shown that the fermionic electromagnetic currents with non-trivial helicity are produced during the level crossing. Cosmic magnetic field generation due to these currents is briefly discussed.