The Use of Nuclear β-decay as a Test of Bulk Neutrinos in Extra Dimensions

Theories which include neutrinos in large extra dimensions can be constrained by nuclear beta decay experiments. We examine universality of β decay strengths of Fermi transitions. From this we find that the extra dimensional Yukawa coupling for a higher dimensional scale of 10 TeV, and two extra dimensions can be constrained to y < ∼ 1. Kinematic implications are also discussed. In particular, a scenario with large mixing will produce a tritium decay endpoint spectrum with a different shape than that for just one massive state. email: [email protected] email: [email protected]