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The EPR-type strangeness correlation in the K K system produced in the reaction pp ™ K K at rest has been tested using the CPLEAR detector. The strangeness was tagged via strong interaction with absorbers away from the creation point. The results are consistent with the QM non-separability of the wave function and exclude a spontaneous wave-function Ž . factorisation at creation CL ) 99.99% . q 1998 Elsevier Science B.V.

Starting from a realistic one-boson-exchange-model fitted to the amplitudes of elastic nucleon-nucleon scattering and the process N N → N ∆ we perform a fully relativistic and gauge invariant calculation for the dilepton production in nucleon-nucleon collisions, including the important effect of propagating the ∆-resonance. We compare the results of our calculations with the latest experimental data on dilepton production. We also show how to implement various electromagnetic formfactors for the hadrons in our calculations without loosing gauge-invariance and discuss their influence on dilepton spectra. * Supported by BMFT and GSI Darmstadt † Part of dissertation of M. Schäfer 0

We report on the first observation of time-reversal symmetry violation through a comparison of the probabilities of K 0 0 0 transforming into K and K into K as a function of the neutral-kaon eigentime t. The comparison is based on the analysis of the neutral-kaon semileptonic decays recorded in the CPLEAR experiment. There, the strangeness of the neutral kaon at ". 0 0 was measured over the interval 1 tt-20 t , thus leading to evidence for time-reversal non-invariance.