Majorana Feynman rules

Feynman rules for fermion-number-violating interactions

“…However, keeping track of the anticommutativity of fermionic operators, we derive Feynman rules for the reversed fermion flow which have signs different from those given in Ref. [3]. As a consequence we only need the well-known propagators for Dirac fermions, we need less vertices than in the conventional treatment, and the RSIF is determined from the permu-tation of the external fermions as usual.…”

“…[3] a first simplification of the Feynman rules for Majorana fermions has been achieved. The number of propagators and vertices has been reduced, and only the vertices without charge-conjugation matrix and the conventional fermion propagator are left.…”

“…We follow the idea described in Ref. [3] of maintaining a continuous fermion flow. This forces one to introduce two analytical expressions for each vertex, one for fermion flow parallel and one for fermion flow antiparallel to the flow of fermion number.…”

“…Moreover, our Feynman rules naturally apply to theories containing explicit charge-conjugate fermion fields, which were not considered in Refs. [3,4].…”

Majorana neutrino masses can save one-family technicolour models

“…where O({p}), O µ ({p}) and O µν ({p}) are general operators which depend on the momenta {p} entering the vertex and where we have used the self conjugacy properties of the Majorana fields [17] . Since the Majorana techni-neutrino mass is being treated as a perturbation to the TC symmetry breaking pattern Eq(2.1) the vertices are functions of the dynamical Dirac self energy, Σ(k 2 ), only.…”