New precise measurements of the Ξ0→Λγ and Ξ0→Σ0γ decay asymmetries

The decay asymmetries of the weak radiative hyperon decays Ξ0→Λγ and Ξ0→Σ0γ have been measured with high precision using data of the NA48/1 experiment at CERN. From about 52 000 Ξ0→Λγ and 15 000 Ξ0→Σ0γ decays, we obtain for the decay asymmetries αΞ0→Λγ=−0.704±0.019stat±0.064syst and αΞ0→Σ0γ=−0.729±0.030stat±0.076syst, respectively. These results are in good agreement with previous experiments, but more precise.