[en] A gas mixture containing nickelocene [Ni(C₅H₅)₂] vapour can be ionized by a N₂-laser beam. This can be used for detector calibration. First tests with a drift chamber are reported. (orig.)

[en] The latent tracks caused by ionizing particles in wire chambers can be simulated by a pulsed laser beam, if molecules having appropriate ionization potential, absorption band structure and vapour pressure are admixed to the chamber gas. This can be used for chamber calibration. First tests with N₂-laser light (337 nm) and Ni(C₅H₅)₂, were extended to include several organic compounds using a pumped tunable dye laser (428-450 nm). (orig.)

[en] A MWPC with cathode-coupled coaxial-cable delay-line readout is described. Special features are: low-mass (new gas mixture), high operating rate, good time- and space resolution. (Auth.)

[en] The authors have analyzed the decay π⁺→μ⁺+γsub(i) in vacuum in flight (psub(π)=350 MeV/c). In this experiment one expects in the neutrino momentum spectrum different lines for different neutrino masses. (Auth.)

[en] Precise measurements of the K X-ray energy spectrum of muonic hydrogen (μ^-p) were made at H₂ gas pressures between 0.25 and 150 torr (T = 300 K). The measured intensity ratios I(Ksub(α))/I(Ksub(tot)) and I(Ksub(β))/I(Ksub(γdelta)...) are compared with the results of new cascade calculations. The pressure dependence of the relative (μp)sub(2S) population was investigated. Its value is (4.24+-0.14)% at 10 torr and (2.21+-0.22)% at 0.25 torr. (orig.)

No abstract available

[en] Muonic hydrogen atoms were produced at 1.0, 0.5 and 0.25 Torr H₂ gas pressure using the magnetic bottle technique. The energy-time correlation of the muonic K-X-rays was determined. The moderation time tausub(m) of the muon needed for the last stage of energy loss (from approx. 2 keV until atomic capture) was measured and is compared with predictions. (orig.)

No abstract available

[en] The Mark J Collaboration at the DESY e⁺e^- collider PETRA presents results on the electroweak reactions e⁺e^-→μ⁺μ^-tau⁺tau^-,μ⁺μ^-γ, and e⁺e^-μ⁺μ^-. The c.m. energy range is 12 to 46.78 GeV. In the μ⁺μ^- and tau⁺tau^- channels the total cross sections and the forward-backward asymmetries are reported and compared with other experiments. The results are in excellent agreement with the standard model. The weak-neutral-current vector and axial-vector coupling constants are determined. The values for muons and tau's are compatible with universality and with the predictions of the standard model. In the μ⁺μ^-γ channel, all measured distributions, including the forward-backward muon asymmetry, are in excellent agreement with the electroweak theory. Our data on the two-photon process, e⁺e^-μ⁺μ^-, agrees with QED to order α⁴ over the entire energy range and the Q² range from 0.7 to 166 GeV²

[en] A novel technique devised to produce light muonic atoms efficiently in low pressure gases (10 to 600 torr at 300K) has been successfully implemented in helium. Muons produced by in-flight decay of 40 MeV/c pions are trapped in a magnetic bottle filled with the low density gas. The high-yield formation of muonic atoms is demonstrated by detecting the characteristic X-rays as well as the μ-decay electrons. (Auth.)