A measurement of the η radiative width Γη→γγ

The radiative width of the η meson has been measured at PETRA in photon-photon collisions. The resulting value is Γ_η→γγ = 0.53±0.04±0.04 keV.     

A note on semibounded pairs of inner products

Using the convexity of the 2-dirnensionai field of values we reprove the well-known result that an inner product that is semibounded on the neutral set of an indefinite inner product of arbitrary dimension is so on the whole space. With this field of values approach we can also remedy some errors in the literature on indefinite inner product spaces.     

Ein verbesserter Existenzsatz für Flächen konstanter mittlerer Krümmung

Let r be a recifiable closed Jordan curve in the euclidean 3-space IR³, and denote by A_r the infimum of the areas of all surfaces bounded by r. Then for every real number H with we show the existence of a surface with boundary curve r having constant mean curvature H (except in possible branching points). This improves a theorem of WENTE. Given an isolated minimal surface bounded by r for sufficiently small |H| we further prove the existence of a surface of constant mean curvature with boundary curve r which is close to the minimal surface.

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Diese Arbeit entstand aus dem ersten Teil meiner Dissertation, die auf Anregung und unter Anleitung von Prof. Dr. S. Hildebrandt geschrieben wurde. Ihm danke ich für seine ständige Unterstützung.     

Gas chromatographic study of volatile oxides and hydroxides of Re, Tc, Os, Ru and Rr-II Thermochromatographic investigations

The enthalpies and entropies of absorption on quartz granules of the oxides and hydroxides of Re, Tc, Os, Ru and Ir have been determined by thermochromatography. The separations of these elements have been achieved with dry and moist oxygen as reactive and carrier gas.     

Observation of a charge asymmetry in e+e− → μ+μ−

The angular distribution and the s dependence of the total cross section for the process e⁺e^? → μ⁺μ^? have been measured using the JADE detector at PETRA. After radiative corrections, a forward-backward asymmetry of ?(11.8±3.8) % was observed at an average centre of mass energy of 33.5 GeV. For comparison, an asymmetry of ?7.8 % is expected on the basis of the standard Glashow-Salam-Weinberg model.     

Messungen von Laserimpulsen im Submillimeterwellen-Bereich mit einem InSb-Detektor

Ohne Zusammenfassung     

The dynamical behavior of periodic surface profiles on metals under the influence of anisotropic surface energy

The kinetics of shaping of periodic surface profiles under the action of surface selfdiffusion were calculated for the special case of anisotropic surface energy. The orientation-dependent surface energy was allowed to contain a local minimum of very high curvature (cusp). The orientation of this cusp was equal to the macroscopic orientation of the crystal surface. The periodic surface profiles exhibited in all cases extended, nearly flat regions centered at the cusp orientation. This type of faceting which causes the profile to be trapezoidal in shape agrees well with experimentally observed profiles on (111) and (100) Ni single crystal surfaces. A procedure is outlined by which the orientation-dependent surface energy along a certain azimuth and the surface self-diffusion coefficient can be extracted from the decay kinetics of faceted periodic surface profiles. This procedure demands the accurate experimental assessment of profile shapes and amplitudes.     

Prompt muons in multiparticle events from e+e− annihilation at petra

We have observed the production of prompt muons in e⁺e^? annihilation in the centre of mass energy range 33.0 GeV to 35.8 GeV. The rate of such muons with momentum greater than 1.4 GeV was measured to be 0.069 ± 0.024 per multiparticle event. When compared with currently accepted models, this rate is consistent with that expected from charm and bottom decays, but does not support the production also of a top quark of mass less than about 15 GeV.