Limits on tensor type weak currents from nuclear and neutron $\beta$~decays

Abstract

The limits on time-reversal invariant tensor-type weak currents from nuclear and neutron $\beta$ decays are evaluated including most recent experimental data. We find that $-0.14\times 10^{-2}<(C_T+C_T^{\prime })/C_A<1.4\times 10^{-2}$ and $-0.16<(C_T-C_T^{\prime })/C_A<0.16$ (90% C.L.), while for the case $C_T=C_T^{\prime }$ the limits are $|C_T/C_A|<3.7\times 10^{-3}$. These limits are shown to be more stringent than those from recent measurements of the radiative pion decay. In addition, the sensitivity of future $10^{-3}$-level correlation measurements is investigated.