Measurement of the Decay ${\Xi }^0\to \Lambda \gamma$ with Entangled ${\Xi }^0{\bar{\Xi }}^0$ Pairs

Abstract

In this Letter, a systematic study of the weak radiative hyperon decay ${\Xi }^0\to \Lambda \gamma$ at an electron-positron collider using entangled ${\Xi }^0{\bar{\Xi }}^0$ pair events is presented. The absolute branching fraction for this decay has been measured for the first time, and is $\left(1.347\pm 0.066_{\mathrm{s}tat.}\pm 0.054_{\mathrm{s}yst.}\right)\times 10^{-3}$. The decay asymmetry parameter, which characterizes the effect of parity violation in the decay, is determined to be $-0.741\pm 0.062_{\mathrm{s}tat.}\pm 0.019_{\mathrm{s}yst.}$. The obtained results are consistent with the world average values within the uncertainties, offering valuable insights into the underlying mechanism governing the weak radiative hyperon decays. The charge conjugation parity ($CP$) symmetries of branching fraction and decay asymmetry parameter in the decay are also studied. No statistically significant violation of charge conjugation parity symmetry is observed.

7 pages, 1 figures

References in corpus (6)

• STCF Conceptual Design Report: Volume 1 -- Physics & Detector
• Number of $J/\psi$ events at BESIII
• The Dynamics of Particle-Particle Correlations and the Ridge Effect in Proton-Proton Collisions
• Joint description of weak radiative and nonleptonic hyperon decays in broken SU(3)
• Precision Measurement of the Decay ${\Sigma }^{+}\to p\gamma$ in the Process $J/\psi \to {\Sigma }^{+}{\bar{\Sigma }}^{-}$
• Hyperon Weak Radiative Decay