Slavnov-Taylor and Ward Identities in the Electroweak Theory

In the framework of the Electroweak Theory we discuss a class of gauge fixing choices suitable for the calculation of electromagnetic processes. We show in particular that, with our choices, beyond the basic Slavnov-Taylor identities guaranteeing the independence of the physical results of the particular gauge fixing, one also has the standard QED Ward identities which play a well known crucial role in the calculation of electromagnetic processes and, in particular, in the analysis of the electromagnetic radiative corrections

Gauge parameter dependence in gauge theories (revised: subsection 2.3)

Dependence on the gauge parameters is an important issue in gauge theories: physical quantities have to be independent. Extending BRS transformations by variation of the gauge parameter into a Grassmann variable one can control gauge parameter dependence algebraically. As application we discuss the anomaly coefficient in the Slavnov-Taylor identity, $S$-matrix elements, the vector two-point-function and the coefficients of renormalization group and Callan-Symanzik equation.Comment: 6, MPI-PhT/94-34, BUTP-94/1

Axial anomalies in gauge theory by exact renormalization group method

The global chiral symmetry of a $SU(2)$ gauge theory is studied in the framework of renormalization group (RG). The theory is defined by the RG flow equations in the infrared cutoff \L and the boundary conditions for the relevant couplings. The physical theory is obtained at \L=0. In our approach the symmetry is implemented by choosing the boundary conditions for the relevant couplings not at the ultraviolet point \L=\L_0\to\infty but at the physical value \L=0. As an illustration, we compute the triangle axial anomalies.Comment: 11 pages + 1 appended EPS figure, LaTeX, UPRF 94-39

Gauge dependence in topological gauge theories

We parametrize the gauge-fixing freedom in choosing the Lagrangian of a topological gauge theory. We compute the gauge-fixing dependence of correlators of equivariant operators when the compactified moduli space has a non-empty boundary and verify that only a subset of these has a gauge independent meaning. We analyze in detail a simple example of such anomalous topological theories, 4D topological Yang-Mills on the four-sphere and instanton number k=1.Comment: 12 pages, TeX , harvma

A nilpotent symmetry of quantum gauge theories

For the Becchi-Rouet-Stora-Tyutin (BRST) invariant extended action for any gauge theory, there exists another off-shell nilpotent symmetry. For linear gauges, it can be elevated to a symmetry of the quantum theory and used in the construction of the quantum effective action. Generalizations for nonlinear gauges and actions with higher order ghost terms are also possible.Comment: RevTeX, 9 pages, several changes to include generalizations to quartic and higher ghost terms and non-linear gauges. Abstract changed. Final version to be publishe

Design and testing of a deployable, retrievable boom for space applications

The Deployable Retrievable Boom which was developed as a part of the joint U.S.-Italian Tethered Satellite System (TSS) is described. The design mission of the boom is to support, deploy, and retrieve an experiment package for the study of the electromagnetic field surrounding the satellite. The mechanism includes a jettisoning provision and deployable harness for the supported payloads connection. The boom is based on a tubular telescopic concept. Particular emphasis is placed on the payload harness connection capability and safety provisions