Limits on Lorentz violation in neutral-Kaon decay

Original · EN

The KLOE collaboration recently reported bounds on the directional dependence of the lifetime of the short-lived neutral kaon Kₛ with respect to the cosmic microwave background dipole anisotropy. We interpret their results in a general framework developed to probe Lorentz violation in the weak interaction. In this approach a Lorentz-violating tensor χμν is added to the standard propagator of the W boson. We derive the Kₛ decay rate in a naive tree-level model and calculate the asymmetry for the lifetime. By using the KLOE data the real vector part of χμν is found to be smaller than 10-2. We briefly discuss the theoretical challenges concerning nonleptonic decays.