Tests of CPT and Quantum Mechanics: experiment

Neutral kaons provide one of the systems most sensitive to quantum mechanics and CPT violation. Models predicting quantum mechanics violation, also related to CPT violation, have been tested at the CPLEAR and KLOE experiments. In this report results of CPLEAR obtained by studying the time evolution of single and two entangled kaons are reviewed. New or improved limits on decoherence and CPT violation parameters have been obtained by KLOE studying the quantum interference in the channel ϕ → K S K L → π + π − π + π − . No deviations from the expectations of quantum mechanics and CPT symmetry have been observed.