Hyperon Physics at BESIII

Abstract

The BESIII detector on the BEPCII collider collected the world’s largest dataset at the peaks of \(J/\psi\), \(\psi(3686)\) and \(\psi(3770)\). The use of polarization and entanglement states in multidimensional angular distribution analysis can provide new probe to the production and decay characteristics of hyperon anti hyperon pairs. In a recent series of studies, significant transverse polarization in hyperon decay has been observed in \(J/\psi\), \(\psi(3686)\) decaying into the \(\Lambda\bar{\Lambda}\), \(\Sigma^{+}\bar{\Sigma}^{-}\), \(\Xi^{0}\bar{\Xi}^{0}\), and \(\Xi^{-}\bar{\Xi}^{+}\) final states. The weak decay parameters of hyperons and antihyperons are also independently determined for the first time. The most accurate testing for direct \(CP\) violation has been achieved.