Search for spatial anisotropy in beta-decays
  Theoretically a possibility of covariance violation in weak decays is not ruled out from the first principles, while there are some models predicting non-covariance revealed in weak interactions. The experimental evidence for isotropy violation in $\beta$-decays was recently reported. We present a study of the dependence of electron flow rate and $\beta$-electron energy in the decay of $Sr^{90}$ with respect to the direction of electron emission. An upper limit of $1.4 \cdot 10^{-5}$ on directional dependence of $\beta$-electron energy was obtained. 
E.Novikov and P.Pakhlov