[en] Preliminary results of the UA1 experiment are presented on the W and Z bosons detected in the leptonic muon decay channel from the 1988/1989 data taking at the CERN Collider. A sample of muon triggered events with an integrated luminosity of 4.7 pb^-1 was collected. Muons were identified by extrapolation of tracks in the central track chamber to tracks in the muon drift chamber. Event samples, background contributions, IVB cross sections, the number of light neutrino families, the width of the W and the underlying event structure are presented, and upper limits for the decay of the type W → π ±γ are given. (R.P.) 19 refs.; 9 figs

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[en] The predicted large charm (∼100 μb) and bottom (∼10 μb) production cross sections at the p bar p collider at CERN (square root σ = 630 GeV) yield about 10⁸ c bar c and 10⁷ c bar b pairs in an integrated luminosity of 1 pb^-1 mainly by the gluon-gluon fusion process. The top quark production rate ([σ_baru + σ_W→tb]) ∼ 1 nb) is expected to give 1000 top events (for m_t = 60 GeV/c²). In this sense the collider is a B-factory. Experimentally these events are tagged by the presence of one or more muons (from the semileptonic decays). The muons are in or nearby a jet from the hadronic fragment. Although the total cross section for c-quark production supersedes the one for b-quark production by about one order of magnitude, as mentioned previously, the muons from the latter process overwhelm the events from charm decay at the muon level. In the naive parton model different quark flavors are produced at p_t > m_q at equal rates with a p^-4_t dependence. The harder fragmentation of the B-mesons (Peterson fragmentation parameter ε_b = 0.02) with respect to the D-meson ε_c = 0.3) and the steeply falling heavy quark production spectrum give higher event rates from the b-quarks, which then are reflected in the muon spectrum. For the same simple reason muons from semileptonic decays from t bar t-produced top (or b') quarks give a higher rate than from b-quarks in a regime where the transverse momentum is larger than the t- (or b'-) quark mass. Contributions from b-quarks are not identified on an event-by-event basis, but are separated on a statistical basis. This simple picture of heavy quark production and detection is in reality distorted in the complex QCD environment

[en] The derivation of the sea level muon spectrum and primary nucleon spectrum from a measured undersea -spectrum in DUMAND requires detailed knowledge of the non-QED muon interaction processes. An uncertainty in the photonuclear cross-section give an error bar of approximately 0.15 for the meson production spectrum. A Monte Carlo study of DUMAND muons has been performed to calculate i) energy loss and its fluctuations, ii) number of interactions per muon passage, iii) rates of interactions. Special attention has been put to the high energy transfer events of the bremsstrahlung and nuclear interaction type processes. These events were treated with the aim to get experimental information on the total inelastic cross-section and its energy behaviour

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[en] The sea level muon energy spectrum can be reasonably well determined at high energies in DUMAND when the photonuclear cross section is known in the 1-50 TeV range. This is possible by distinguishing between hadronic and electromagnetic showers from the muon interactions. The longitudinal development of hadronic showers shows only slightly different behaviour compared to purely electromagnetic cascades, in the shower length and in number of particles at maximum of development. From Monte Carlo simulations of cascades methods of separating the two types of cascades are derived. A spatial resolution of about 1m corresponding to a time resolution of a few nsec is necessary for a separation on a statistical basis. An event by event separation seems not possible

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[en] Some essential results in the field of strong interaction in high energy physics are presented. These results have been obtained from experiments at proton accelerators over the past three years. (orig.)