General one-loop expressions for the diagonal and transition electromagnetic moments of spin-1/2 fermions

Abstract

Electrically neutral spin-1/2 fermions can interact via Yukawa or gauge couplings with electrically charged particles, leading to quantum-induced couplings between the neutral fermion and the photon. In this paper, we present general expressions for the diagonal and transition electromagnetic moments of Dirac and Majorana spin-1/2 fermions generated at the one-loop level. We also briefly discuss the implications of these results for several neutral spin-1/2 fermions of phenomenological interest, such as neutral components of $SU(2{)}_L$ multiplets (which are potential candidates for dark matter) or Standard Model neutrinos.

arXiv comment34 pages, 7 figures