Charge and magnetic moment of the neutrino in the background field method and in the linear R-xi(L) gauge

We present a computation of the charge and the magnetic moment of the neutr ino in the recently developed electro-weak Background Field Method and in t he linear R-xi(L) gauge. First, we deduce a formal Ward-Takahashi identity which implies the immediate cancellation of the neutrino electric charge. T his Ward-Takahashi identity is as simple as that for QED. The computation o f the (proper and improper) one loop vertex diagrams contributing to the ne utrino electric charge is also presented in an arbitrary gauge, checking in this way the Ward-Takahashi identity previously obtained. Finally, the cal culation of the magnetic moment of the neutrino, in the minimal extension o f the Standard Model with massive Dirac neutrinos, is presented, showing: i ts gauge parameter and gauge structure independence explicitly.