[en] This paper states that on the basis of the 152,000 recorded B-bar B pairs, the ARGUS collaboration improved its measurement of B⁰-bar B⁰ mixing, looked in various ways for (b → u) transitions and rare B decays. The mixing parameter r is stable at 0.21 ± 0.08. An upper limit is obtained for the ratio of the Kobayashi-Maskawa matrix elements |V_ub|/|V_cd< 18% at 90% CL. Upper limits are also given for a large number of rare B decays mediated by penguin diagrams

[en] Using the ARGUS detector at the DORIS II storage ring we observed B⁰-B-bar⁰ oscillations in Υ(4S) decays. One explicitly mixed event, a decay Υ(4S) → B⁰B⁰, has been completely reconstructed. Furthermore, we observe a 4.0 standard deviation signal of 24.8 events with like-sign lepton pairs and a 3.0 standard deviation signal of 4.1 events containing one reconstructed B⁰(B-bar⁰) and an additional fast l⁺(l^-). This leads to the conclusion that B⁰-B-bar⁰ mixing is substantial. For the mixing parameter we obtain r = 0.21 ± 0.08. (author)

[en] At the HERA 800 GeV proton storage ring at DESY a fixed target experiment to study CP violation in B meson decays has been proposed. It is based on the observation of the decay B⁰_d→J/ψK⁰_S, with the J/ψ decaying into a lepton pair.With a time between proton bunches of 96ns and interaction rates of 40MHz the trigger has to reject minimum bias events by 5 orders of magnitude, leaving the signal essentially intact.The 3-level hierarchical trigger relies on the detection of lepton pairs from J/ψ decays with the additional requirement of a finite flight path of the J/ψ's parent particle. The design of such a trigger system is presented, with special emphasis on the most challenging level-1 trigger step. (orig.)

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[en] The ARGUS detector at the electron-positron storage ring DORIS consists of various particle detectors arranged in cylindrical symmetry in and around an axial magnetic field. A fast secondary trigger processor has been designed to find and count circular tracks in the r-PHI-plane of the detector that originate from the interaction point. The processor serves as a filter in the trigger system of the ARGUS detector and is expected to reduce the rate of background triggers by two orders of magnitude. The processor hardware is built in ECL to perform simple operations with very high speed and partly in parallel. The track finding process takes about 9 μs plus 3 μs for each encountered track element. Control information is stored in memories that may be loaded via CAMAC from the online computer allowing easy adaption of the processor to different experimental conditions. (orig.)

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[en] At DESY future B-physics experiments are under study. An asymmetric B-factory, colliding e⁺e^- with 12 GeV on 2.3 GeV appears most attractive. The machine concept, a detector and computer simulations for experiments on CP-violation, B_santiB_s mixing and b→u transitions are presented

[en] The reaction e⁺e^- → hadrons has been measured in the UPSILON and UPSILON' region using the DASP detector at the DESY storage ring DORIS. The following final results are obtained: Rsub(had) (9.5 GeV) = 3.73 +- 0.16 +- 0.28, GAMMAsub(ee)(UPSILON) = (1.23 +- 0.08 +- 0.12) keV, Bsub(μμ)(UPSILON) = (= 3.2 +- 1.3 +- 0.3)%, GAMMAsub(ee)GAMMAsub(had)/GAMMAsub(tot)(UPSILON) = (0.55 +- 0.11 +- 0.06) keV, and M(UPSILON')-M(UPSILON) = (556 +- 10) MeV. (orig.)

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No abstract available