Measurement of CP,T and CPT violation parameters in the Neutral Kaon system at CPLEAR

The CPLEAR experiment at CERN measures the time dependent decay rate asymmetries of initially pure K ⁰ and overlineK⁰ states to study CP,T and CPT symmetries in the neutral kaon system. The latest results on η_+-, Δm and x are reported, as well as direct tests of T violation and CPT violation in K ⁰- overlineK⁰ oscillations. Our results are consistent with CPT invariance and allow for an improved limit on the K ⁰- overlineK⁰ mass difference. Further, a possible loss of quantum coherence of the neutral kaon system has been tested to a level near the Planck scale.