βasymmetry parameter in the decay ofIn114

Abstract

The $\ensuremath{\beta}$-asymmetry parameter $\mathit{\~A}$ for the pure Gamow-Teller decay of $^{114}\mathrm{In}$ is reported. The low-temperature nuclear orientation method was combined with a GEANT4-based simulation code allowing us, for the first time, to address in detail the effects of scattering and the magnetic field. The result, $\mathit{\~A}=\ensuremath{-}0.994\ifmmode\pm\else\textpm\fi{}0.{010}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}0.{010}_{\mathrm{syst}}$, constitutes the most accurate value for the asymmetry parameter of a nuclear $\ensuremath{\beta}$ transition to date. The value is in agreement with the Standard Model prediction of $\mathit{\~A}=\ensuremath{-}1$ and provides new limits on tensor-type charged weak currents.