Beyond the Standard Model interactions in -decay of tritium

We discuss the role of beyond the Standard model (SM) interactions (effective scalar and tensor interactions) in the β -decay of tritium. The theoretical framework is the Elementary Particle Treatment (EPT) of the transition 3 H → 3 He + e − + ν ¯ e , which allows one to derive relativistic form for the β -endpoint spectrum and to take nuclear recoil into account. We find that the interference of scalar and tensor charge-changing interactions, weaker than the V – A SM interaction, with the SM interaction cannot produce effects near the end point of the tritium β -decay spectrum which are of different character from those produced by the purely kinematic effect of the neutrino mass expected within the SM.