Deux trajectoires de regge dans la reaction πp → πn

The possibility of describing the high-energy reaction π⁻p^→π⁰n with two Regge trajectories (t) and _'(t) is studied in more detail. These trajectories are assumed to be exactly linear in t, with (t) constrained to pass through (m²) = 1. We examine hypotheses in which (t) obeys either the Gell-Mann mechanism or the Chew mechanism, and in which '(t) is or is not a conspiring trajectory. The model is in good agreement with the data in practically all cases; greater experimental accuracy would be necessary to distinguish between the various hypothesis. Predictions are given for the neutron polarization at |t| < 1 GeV².     

Reaktionskinetik der Ozonbildung in der Sauerstoffglimmentladung

Hg-light absorption at λ = 2537 ǎ by O₃ has been used to measure the concentration of O₃ in the positive column of an oxygen glow discharge under the nonstationary conditions of the Q-form (tube diameter 3:4 cm). For all gas pressures investigated (p = 7 — 12 torr) the O₃ density (n₃) as a function of the current reaches a remarkable maximum at i ≈ 15 mA. n₃ ^max was found to increase almost linearly with the gas pressure. At i = 80 mA, on the other hand, n₃ increases according to a quadratic relation. In order to understand the dependence of n₃ on the pressure and on the current density (or equivalently on the electron density n_e) a kinetic model previously developed has been used involving the following particles . For example, it can be shown that in the region of the maximum of n₃ one main production process of ozone is the associative detachment reaction . The calculated maximum of the ozone density is higher than the measured one and appears at higher electron density.     

Anvendung und Perspektiven der Strahlungsvernetzung in der Volkswirtschaft der DDR

Zum angegebenen Thema wurde vom Zentralinstitut für Festkörperphysik und Werkstofforschung der Akademie der Wissenschaften der DDR (ZfFW) gemeinsam mit dem Bezirksvorstand Dresden der Kammer der Technik am 9. 10. 1975 ein Tageskolloquium veranstaltet. Es wurden 100 Teil-nehmer registriert, wobci Kombinate und Betriebe zur Anwendung von Plasten und Elasten stark vertreten waren.     

Interferometrische Bestimmung der Gastemperatur in der Stickstoffniederdruckentladung

A Michelson-interferometer in combination with a He-Ne-laser was used to determine the gas temperature in a nitrogen low pressure gas discharge. With this method the radial temperature profile could be measured to about 96% of the tube radius. Moreover rotational temperatures were measured with a 2 m-grating spectrograph from the spectrum of N₂- and N₂⁺-bands. In the range from 4 to 10 torr and 25 to 100 mA gas temperatures between 460 and 890 K were measured with the belonging rotational temperature from 620 to 1170 K. At pressures below 10 torr a difference of the rotational temperatures from the first negative and the second positive system was found. A qualitative consideration on the mechanism of the radial heat conductivity in the positive column was added.     

Zur Definition der Drehimpulseigenfunktionen in der Vektormesontheorie

There are three possibilities for the introduction of angular momentum eigenfunctions in the vector-meson-theory: 1. Multipole fields, 2. orbital angular momentum eigenfunctions, 3. helicity eigenfunctions. We shall define these functions by eigenvalue equations and present their mutual relationship. In analogy to the usual momentum quantization we may quantize the field with respect to each of the three systems of angular momentum eigenfunctions.     

Greensche Funktionen in der Theorie der Kernmaterie

The aim of this article is the representation of the theory of nuclear matter with the technique of many-body Green functions. We have treated the theory of Green functions thoroughly in the first chapters taking support of the functional method, which offers a convenient approach to the construction of the theory. After treatment of the properties of the exact two-point function and of the effective single-particle potential, preconditions and properties of the approximate solutions are discussed. Results achieved todate are treated in chapter 6. Brueckner theory and allied methods are not further discussed, since these are sufficiently known. The theory of linear response, being important for the semi-phenomenological treatment of real atomic nuclei, is presented in appendix A.     

Formfaktoren in der klassischen Dynamik der Teilchen

The classical dynamics of extended particles is considered. The restrictions imposed on the form factors by the Lorentz and gauge invariance as well by causality are shown.