Comments on CP, T and CPT Violation in Neutral Kaon Decays

TL;DR

This paper discusses recent experimental data on neutral kaon decay asymmetries, providing evidence for T violation and setting bounds on CPT violation, thereby clarifying the nature of symmetry violations in kaon decays.

Contribution

It analyzes new experimental results to confirm T violation and constrain CPT violation in neutral kaon decays, offering updated bounds and clarifications.

Findings

CPT and $ riangle S = riangle Q$ rule violations are constrained by recent data.

Data from CPLEAR confirms direct evidence for T violation.

KTeV asymmetry limits CPT violation.

Abstract

We comment on CP, T and CPT violation in the light of interesting new data from the CPLEAR and KTeV Collaborations on neutral kaon decay asymmetries. Other recent data from the CPLEAR experiment, constraining possible violations of CPT and the $\Delta S = \Delta Q$ rule, exclude the possibility that the semileptonic-decay asymmetry $A_{T}$ measured by CPLEAR could be solely due to CPT violation, confirming that their data constitute direct evidence for T violation. The CP-violating asymmetry in $K_L \to e^-e^+\pi^-\pi^+$ recently measured by the KTeV Collaboration does not by itself provide direct evidence for T violation, but we use it to place new bounds on CPT violation.