Gj. Stephenson et al., Tritium beta decay, neutrino mass matrices, and interactions beyond the standard model - art. no. 093013, PHYS REV D, 6209(9), 2000, pp. 3013
The interference of charge changing interactions, weaker than the V-A stand
ard model (SM) interaction and having a different Lorentz structure, with t
hat SM interaction, can, in principle, produce effects near the end point o
f the tritium beta decay spectrum which are of a different character from t
hose produced by the purely kinematic effect of neutrino mass expected in t
he simplest extension of the SM. We show that the existence of more than on
e mass eigenstate can lead to interference effects at the end point that ar
e stronger than those occurring over the entire spectrum. We discuss these
effects both for the special case of Dirac neutrinos and the more general c
ase of Majorana neutrinos and show that, for the present precision of the e
xperiments, one formula should suffice to express the interference effects
in all cases. Implications for "sterile" neutrinos are noted.