Neutrino mass constraints on beta decay
  Using the general connection between the upper limit on the neutrino mass and the upper limits on certain types of non-Standard Model interaction that can generate loop corrections to the neutrino mass, we derive constraints on some non-Standard Model $d\to ue^-\bar{\nu}$ interactions. When cast into limits on $n\to pe^-\bar{\nu}$ coupling constants, our results yield constraints on scalar and tensor weak interactions improved by more than an order of magnitude over the current experimental limits. When combined with the existing limits, our results yield $|C_S/C_V|\alt 5\times 10^{-3}$, $|C'_S/C_V|\alt 5\times 10^{-3}$, $|C_T/C_A| \alt 1.2\times 10^{-2}$ and $|C'_T/C_A| \alt 1.2\times 10^{-2}$. 
Takeyasu M. Ito and Gary Prezeau