Examining CP Symmetry in Strange Baryon Decays

TL;DR

This paper investigates CP symmetry in strange baryon decays, comparing decay distributions of hyperons and their antiparticles, and reports on experimental efforts to detect CP violation with high sensitivity.

Contribution

It presents experimental analysis of CP symmetry in hyperon decays and discusses a follow-up experiment aiming for higher sensitivity to CP violation.

Findings

No CP-odd effect observed at the 10^{-2} level in Fermilab E756

Follow-up HyperCP experiment aims for sensitivity of 10^{-4}

Status update on experimental searches for CP violation in strange baryons

Abstract

Non-conservation of CP symmetry can manisfest itself in non-leptonic hyperon decays as a difference in the decay parameter between the strange-baryon decay and its charge conjugate. By comparing the decay distribution in the $\Lambda$ helicity frame for the decay sequence $\Xi^{-} \to \Lambda \pi^{-}$, $\Lambda \to p \pi^{-}$ with that of $\bar{\Xi}^{+}$ decay, E756 at Fermilab did not observe any CP-odd effect at the $10^{-2}$ level. The status of a follow-up experiment, HyperCP (FNAL E871), to search for CP violation in charged $\Xi-\Lambda$ decay with a sensitivity of $10^{-4}$ is also presented.