Recent results on CP violation from the CPLEAR experiment

Abstract The CPLEAR experiment is aiming at precise CP violation tests using initially pure K 0 - and K 0 beams from the intense source provided by the annihilation of the LEAR p - beam in hydrogen. The strangeness tagging efficiency and the systematic errors have been studied and found to be in agreement with the design specifications. The measurement of the differential time asymmetry of the π+π− decays allowed the direct observation of differences in the decay rates of particles and antiparticles. The CP violating parameters were determined as |ν±| = (2.32 ± 0.14) · 10−3 and ψ± = 42.3° ± 4.4°. First results in the reconstruction and analysis of the neutral kaon decays into two neutral pions and the Ke3 decay are presented.