Two component theory and electron magnetic moment

The two-component formulation of quantum electrodynamics is studied. The relation with the usual Dirac formulation is exhibited, and the Feynman rules for the two-component form of the theory are presented in terms of familiar objects. The transformation from the Dirac theory to the two-component theory is quite amusing, involving Faddeev-Popov ghost loops of a fermion type with bose statistics. The introduction of an anomalous magnetic moment in the two-component formalism is simple; it is not equivalent to a Pauli term in the Dirac formulation. Such an anomalous magnetic moment appears not to destroy the renormalizability of the theory but violates unitarity.Comment: 17 pages, tex, gz-compressed tar fil

Perturbation Theory and Relative Space

The validity of non-perturbative methods is questioned. The concept of relative space is introduced.Comment: 12 pages, report UM-TH-94-1

Detecting short periods of elevated workload. A compari­son of nine workload assessment techniques

The present experiment tested the merits of 9 common workload assessment techniques with relatively short periods of workload in a car-driving task. Twelve participants drove an instrumented car and performed a visually loading task and a mentally loading task for 10, 30, and 60 s. The results show that 10-s periods of visual and mental workload can be measured successfully with subjective ratings and secondary task performance. With respect to longer loading periods (30 and 60 s), steering frequency was found to be sensitive to visual workload, and skin conductance response (SCR) was sensitive to mental workload. The results lead to preliminary guidelines that will help applied researchers to determine which techniques are best suited for assessing visual and mental workload

Muon anomalous magnetic moment due to the brane-stretching effect

We investigate the contribution of extra dimensions to the muon anomalous magnetic moment by using an ADD-type 6-dimensional model. This approach analyzes the extent of the influence of classical brane fluctuations on the magnetic moment. When we consider that the brane fluctuations are static in time, they add new potential terms to the Schr{\"o}dinger equation through the induced vierbein. This paper shows that the brane fluctuation is responsible for the brane-stretching effect. This effect would be capable of reproducing the appropriate order for recent Brookhaven National Laboratory measurements of the muon (g-2) deviation.Comment: 17 pages, 1 figure, minor changed, accepted for Phys. Rev.

Rostering from staffing levels: a branch-and-price approach

Many rostering methods first create shifts from some given staffing levels, and after that create rosters from the set of created shifts. Although such a method has some nice properties, it also has some bad ones. In this paper we outline a method that creates rosters directly from staffing levels. We use a Branch-and-Price (B\&P) method to solve this rostering problem and compare it to an ILP formulation of the subclass of rostering problems studied in this paper. The two methods perform almost equally well. Branch-and-Price, though, turns out to be a far more flexible approach to solve rostering problems. It is not too hard to extend the Branch-and-Price model with extra rostering constraints. However, for ILP this is much harder, if not impossible. Next to this, the Branch-and-Price method is more open to improvements and hence, combined with the larger flexibility, we consider it better suited to create rosters directly from staffing levels in practice

Imaginary part of the electromagnetic lepton form factors

The charge $F_1(0)$ and the magnetic $F_2(0)$ form factors of heavy charged leptons have been shown in the framework of the perturbation theory to have imaginary part. The imaginary parts of the form factors for muon and tau lepton have been calculated at the two-loop level in the Standard Model. The effects where these imaginary parts could manifest themselves are discussed.Comment: New references added, the last section modified; final version to appear in Phys. Lett. B; LaTeX, 10 pages, 5 eps-figures include

Equivalence Theorem and Dynamical Symmetry Breaking:

The equivalence theorem, between the longitudinal gauge bosons and the states eaten up by them in the process of symmetry breaking, is shown to be valid in a class of models where the details of dynamical symmetry breaking makes it obscure.Comment: DOE-ER\,40757-023 / CPP-93-23 8 pages LaTeX [**Two references have been added; no change in the text**

\order(\Gamma) Corrections to WW pair production in e+e−e^+e^- and γγ\gamma\gamma collisions

Several schemes to introduce finite width effects to reactions involving unstable elementary particles are given and the differences between them are investigated. The effects of the different schemes is investigated numerically for $W$ pair production. In $e^+e^-\to W^+W^-$ we find that the effect of the non-resonant graphs cannot be neglected for \sqrt{s}\geq400\GeV. There is no difference between the various schemes to add these to the resonant graphs away from threshold, although some violate gauge invariance. On the other hand, in the reaction $\gamma\gamma\to W^+W^-$ the effect of the non-resonant graphs is large everywhere, due to the $t$-channel pole. However, even requiring that the outgoing lepton is observable ($p_\perp > .02\sqrt{s}$) reduces the contribution to about 1\%. Again, the scheme dependence is negligible here.Comment: 9 pages plus 6 with figures (.uu at end, also available with anonymous ftp from pss058.psi.ch [129.129.40.58]), LaTeX, LMU-21/92, PSI-PR-93-05, TTP92-3