Mixing and Radiative Corrections at LEP I
We present a method for a common treatment of Z ′ exchange, QED corrections, and weak loops in e + e − annihilation. QED corrections are taken into account by convoluting a hard-scattering cross section containing γ, Z, and Z ′ exchange. Weak corrections and ZZ ′ mixing are treated simultaneously by a generalization of weak form factors. Using the properly extended Standard Model program for the Z line shape, ZF I T T ER , we perform and compare two different analyses of the 1990 LEP I data in terms of theories based on the E 6-group and in terms of LR-symmetric models. From the LEP I data alone, the ZZ ′ mixing angle may be limited to |θ M | ≤ 0.01 and the Z ′ mass to M 2 > 118–148 GeV, depending on the model (95% CL).
Elementary Particle Theory of Composite Particles
Any nonrelativistic theory may be rewritten by introducing fictitious elementary particles with arbitrary properties. No physical predictions are affected, provided that the interaction part of the Hamiltonian is correspondingly modified. The fictitious elementary particle provides a good representation of a real composite particle if the modified interaction is sufficiently weakened for perturbation theory to work. It corresponds to a truly elementary particle with infinite bare mass, and hence with $Z=0$. We show how the latter condition yields a sum rule for the coupling of a composite particle to its constituents as a function of energy. The sum rule can be used to evaluate such coupling constants as that for the proton-electron-hydrogen vertex. The mathematical method used is that developed by Schmidt for the study of the Fredholm equation, and corresponds to the extraction of a single factor from the full Fredholm determinant.
Electron dose-rate conversion factors for external exposure of the skin from uniformly deposited activity on the body surface.
Dose-rate conversion factors have been calculated for external exposure of the skin from electrons emitted by sources that are deposited uniformly on the body surface. The dose-rate factors are obtained from electron scaled point kernels developed by Berger (Be71; Be73; Be74). The dose-rate factors are calculated at depths of 4, 8, and 40 mg cm-2 below the body surface as recommended by Whitton (Wh73), and at a depth of 7 mg cm-2 as recommended in ICRP Publication 26 (ICRP77). The dependence of the dose-rate factors at selected depths on the energy of the emitted electrons is displayed. The dose-rate factors for selected radionuclides of potential importance in radiological assessments are tabulated.