[en] No evidence for heavy neutrinos with a mass in the range 10-1750 MeV decaying into two electrons and one light neutrino was found in a search performed in the horn-focused wide-band neutrino beam and in the neutrino beam produced by the dump of 400 GeV protons in a copper target. The wide-band beam experiment is sensitive to neutrinos with a mass below 490 MeV, and for masses greater than 250 MeV yields an upper limit at 90% c.l. on the square of the neutrino mixing angle of approximately equal 10^-6. In the beam-dump experiment an upper limit on the square of the neutrino mixing angle of approximately equal to 10^-10 was obtained in the neutrino mass range around 170 MeV, assuming that the neutrino associated with the tau lepton is massive. If no assumption is made on the nature of the heavy neutrino, a limit of approximately equal to 10^-7 is obtained in the mass range around 1500 MeV

[en] The observation of the K⁰, anti K⁰ decay asymmetry is a direct proof of CP violation. In this paper preliminary experimental results obtained by studying the decays into π⁺π^- are reported. (orig.)

[en] The CPLEAR experiment at CERN has been designed to measure CP, T, and CPT violating effects in the neutral kaon system by observing particle-antiparticle asymmetries. The experimental method and first results obtained from the analysis of the π⁺π^- and semileptonic decays are discussed. (orig.)

[en] Limits at 90% c.l. on the square of the mixing strength vertical bar U_τ4 vertical bar² between ν_τ and a mostly isosinglet heavy neutrino with mass in the range 10-290 MeV/c² are reported. The results were derived using the negative result of a search for neutral particles decaying into two electrons conducted by the CHARM Collaboration in a neutrino beam dump experiment. Upper limits congruent with 10^-4 were obtained for neutrino masses larger than 160 MeV/c²

[en] Searches for heavy unstable neutrinos produced in i) meson decay, ii) light-neutrino interactions, and iii) e/sup +/e/sup -/ annihilation are reported. No evidence of their existence was found. The searches were sensitive to neutrino masses in the range 0.01-18 GeV. The limits obtained on the square of the neutrino mixing angles vary between 10/sup -3/ and 5x10/sup -9/ depending on the neutrino mass

[en] The possibility of identifying the hadronic or electromagnetic nature of a shower in a calorimeter detecting the delayed e⁺ from π⁺ → μ⁺ → e⁺ decay chain is discussed. The rejection power has been estimated in some cases. (Auth.)

[en] The experimental requirements to obtain a determination of ε'/ε with a precision of ≅ 10^-4 in an e⁺e^- φ factory experiment are discussed. The present measurements of the CP violation parameters ε'/ε are compatible with zero and have an error of 10^-3. The aim of the next generation of experiments is to improve this precision by a factor of 10. The apparatus described can also allow the investigation of other interesting physics subjects in an e⁺e^-φ factory. (R.P.) 10 refs., 2 figs., 3 tabs

[en] Published in summary form only

[en] This paper reports first results of a study performed to define the parameters of a detector adequate for the study of CP violation effects at an e⁺e^- φ factory. (orig.)

[en] A monitoring system has been developed for the antiproton beam used in experiments on the CP violating decays of K⁰and bar K⁰ by the CP Lear collaboration at Lear, Cern. The beam position is measured by means of two small MWPCs. In each MWPC two anode wires, 8 mm apart, provide gas amplification. The position of the beam is obtained form induced current signals on cathode strips. A small scintillator (O7 mm, thickness 1 mm) gives a signal to be included in the trigger. The scintillation light is guided to a PM outside the solenoid by means of 5 m long PMMA (plexiglass) fibers. The system is mounted on the beam pipe, close to the center of the experimental setup. The beam position resolution is better than 0.5 mm, the time resolution ∼100 ps