Speaker
Description
Based on the large $J/\psi$ and $\psi(3686)$ data samples collected at BESIII, recent studies have established significant transverse polarization in hyperon--antihyperon pairs, including $\Lambda\bar{\Lambda}$, $\Sigma\bar{\Sigma}$, $\Xi\bar{\Xi}$, and $\Omega^- \bar{\Omega}^{+}$. These measurements have enabled the first model-independent determination of the $\Omega^-$ spin. The observed nonzero polarization further allows independent determinations of hyperon and antihyperon decay parameters, providing precise tests of direct CP violation.
BESIII also provides a unique opportunity to search for hyperon electric dipole moments (EDMs) using entangled hyperon--antihyperon pairs produced in $J/\psi$ decays. This method is expected to reach sensitivities of order $10^{-19}\, e\cdot\mathrm{cm}$ for $\Lambda$, $\Sigma^{+}$, $\Xi^{-}$, and $\Xi^{0}$, surpassing previous limits by several orders of magnitude. These studies demonstrate the strong potential of hyperon physics as a probe of physics beyond the Standard Model, with further advances expected at the future STCF.
| Collaboration | BESIII |
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