  Given the most general Lorentz invariant four-fermion effective interaction
possible for two neutrinos and two charged fermions, whether quarks or leptons,
all possible 2-to-2 processes involving two neutrinos, whether Dirac or
Majorana ones, and two charged fermions are considered. Explicit and convenient
expressions are given for the associated differential cross-sections. Such a
parametrization should help assess the sensitivity to physics beyond the
Standard Model of neutrino beam experiments which are in the design stage at
neutrino factories.
