Deuteron production in collisions of 250 GeV/c Pi+ and K+ mesons with Al and Au nuclei

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Direct soft photon production in K+p and pi+p interactions at 250 GeV/c

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Triple Regge analysis of inclusive lambda production in K+p and Pi+p interactions at 250 GeV/c

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A study of double pomeron exchange in Pi+ p and K+p interactions at 250 GeV/c

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A study of radiative muon-pair events at Z0 energies and limits on an additional Z′ gauge beson

An analysis is reported on the channel e+e-→μ+μ- (nγ), n=1,2..., using data taken with the DELPHI detector at LEP from 1990 to 1992. Differential cross sections of the radiative photons as a function of photon energy and of the angle between the photon and the muon are presented. No significant deviations from expectations are observed. The data are also used to extract the muon-pair cross section and asymmetry below the Z0 peak by using those events with relatively hard initial state radiative photon(s). The measured cross section and asymmetry show no significant deviation from the Standard Model expectations. These results together with the DELPHI cross section and asymmetry measurements at the LEP energies from the 1990 to 1992 running periods are used to determine limits on the Z0-Z′ gauge boson mixing angle θZ′ and on the Z′ mass. There is no indication of the existence of a Z′; the limits obtained on the mixing angle substantially improve upon existing limits. The 95% confidence level allowed ranges of θZ′ in various models are: {Mathematical expression} © 1995 Springer-Verlag

Search for pair-produced heavy scalars in Z0 decays

A search for charged Higgs bosons decaying into quarks is described, based on statistics of around 1.7 million hadronic Zo decays detected in DELPHI. Despite the very high background from standard hadronic decays of the Zo, masses in the range up to 43.5 GeV/c2 are excluded at the 95% confidence level. After combination with a search for leptonic decays, this mass limit is extended to cover all branching ratios. A similar analysis sets new limits on the possible production of any pair-produced heavy scalar decaying into a pair of jets, such as neutral Higgs bosons in a two doublet scheme and diquarks. © 1994 Springer-Verlag

Production of strange B-baryons decaying into Ξ∓-ℓ∓ pairs at LEP

An excess of events containing, in a jet, a samesign Ξ∓-ℓ∓ pair as compared to those with an oppositesign Ξ∓-ℓ± pair has been observed in an analysis of 1.7 million hadronic Z0 decays collected by the DELPHI detector at LEP between 1991 and 1993 inclusive. The probability for this signal to come from non B-baryon decays is less than 5×10-4. The measured production fraction corresponds to:[Figure not available: see fulltext.] per lepton species, averaged for electrons and muons and assuming that the two channels have an equal contribution. Semileptonic decays of Λb baryons can account for less than 10% of these events and the major part of the signal has to originate from Ξb semileptonic decays. Using the subsample of these events where the Ξ∓ trajectory has been measured in the Vertex Detector, the lifetime of B-baryons producing a Ξ∓ in their semileptonic decay final state is found to be: {Mathematical expression} © 1995 Springer-Verlag