New Precise Measurements of the $\xilamgam$ and $\xisiggam$ Decay Asymmetries

TL;DR

This paper reports high-precision measurements of decay asymmetries in weak radiative hyperon decays Xi0 to Lambda gamma and Sigma0 gamma, providing more accurate data that align with previous findings.

Contribution

The study provides the most precise measurements to date of decay asymmetries in Xi0 radiative decays, improving upon prior experimental accuracy.

Findings

Decay asymmetry alpha(Xi0 to Lambda gamma) = -0.704 +/- 0.019 (stat) +/- 0.064 (syst)

Decay asymmetry alpha(Xi0 to Sigma0 gamma) = -0.729 +/- 0.030 (stat) +/- 0.076 (syst)

Results agree with previous experiments but with higher precision.

Abstract

The decay asymmetries of the weak radiative Hyperon decays Xi0 \to Lambda gamma and Xi0 \to Sigma0 gamma have been measured with high precision using data of the NA48/1 experiment at CERN. From about 52000 Xi0 \to Lambda gamma and 15000 Xi0 \to Sigma0 gamma decays, we obtain for the decay asymmetries alpha(Xi0 \to Lambda gamma) = -0.704 +/- 0.019(stat) +/- 0.064(syst) and alpha(Xi0 \to Sigma0 gamma) = -0.729 +/- 0.030(stat) +/- 0.076(syst), respectively. These results are in good agreement with previous experiments, but more precise.