A data sample of 1.7 fb−1 has been analyzed by the KLOE experiment at
DAΦNE to study the distribution of the difference in the kaon decay times Δt, of
ϕ→KSKL→π+π−π±e∓ν and
ϕ→KSKL→π±e∓νπ0π0π0.
Tests of T, CP and CPT symmetries in the neutral kaon system are performed by direct comparison of the probabilities of a kaon transition process and the symmetry-conjugate transition. The exchange of "in" and "out" states required for genuine T and CPT tests
is fulfilled exploiting the entanglement of kaon pairs produced at the ϕ-factory.
We were able, by the comparison of the measured Δt distributions in the asymptotic region Δt≫τS, to directly test for the first time T and CPT symmetries in kaon transitions with a few percent precision and to observe CP violation in transitions from CP odd eigenstates to flavour eigenstates, K0 and ¯K0.
