T.E. Clark

An SO(10) supersymmetric grand unified theory

Abstract A realistic supersymmetric SO(10) grand unified theory is explicitly constructed. The neutrino masses turn out to be 10−5 eV or less. It is also found that the proton life time can be longer than 1031 yr.

Standard model Higgs boson-inflaton and dark matter

The standard model Higgs boson can serve as the inflaton field of slow roll inflationary models provided it exhibits a large nonminimal coupling with the gravitational scalar curvature. The Higgs boson self interactions and its couplings with a standard model singlet scalar serving as the source of dark matter are then subject to cosmological constraints. These bounds, which can be more stringent than those arising from vacuum stability and perturbative triviality alone, still allow values for the Higgs boson mass which should be accessible at the LHC. As the Higgs boson coupling to the dark matter strengthens, lower values of the Higgs boson mass consistent with the cosmological data are allowed.

Goldstino couplings to matter

A nonlinearly realized supersymmetric action describing the invariant couplings of the Goldstino to matter is constructed. Using the Akulov-Volkov Lagrangian, any operator can be made part of a supersymmetric-invariant action. Of particular interest are interaction terms which include the product of the Akulov-Volkov Lagrangian with the ordinary matter Lagrangian as well as the coupling of the product of the covariant derivative of the Goldstino field to the matter supersymmetry current. The latter is the lowest dimensional operator linear in the Goldstino field. A Goldstino Goldberger-Treiman relation is established and shown to be satisfied by the effective action. {copyright} {ital 1996 The American Physical Society.}

Interactions of light gravitinos

In models of spontaneously broken supersymmetry, certain light gravitino processes are governed by the coupling of their Goldstino components. The rules for constructing SUSY and gauge invariant actions involving the Goldstino couplings to matter and gauge fields are presented. The explicit operator construction is found to be at variance with some previously reported claims. A phenomenological consequence arising from light gravitino interactions in supernova is reexamined and scrutinized. {copyright} {ital 1998} {ital The American Physical Society}

Supersymmetric effective Lagrangians for matter-goldstone multiplet interactions

Abstract The supersymmetric effective lagrangian describing the spontaneous breakdown of the group G to an invariant subgroup H is constructed, which includes the invariant coupling of the nonlinearly transforming Goldstone superfields to linearly transforming matter superfields.

Internal symmetry currents and supersymmetric effective lagrangians

Abstract A supersymmetric and non-linearly realized internally symmetric action is constructed from the super Kahler potential of Goldstone scalar superfields. Noethers theorem in superspace is derived and the associated superfield of currents defined. The currents are used to derive a super Dashen formula relating the (quasi) Goldstone masses and decay constants to the symmetry breaking part of the theory and to supersymmetrically gauge the invariant subgroup as well as the full group.

Wilson renormalization-group analysis of theories with scalars and fermions

Abstract The continuous block-spin (Wilson) renormalization-group equation governing the scale dependence of the action is constructed for theories containing scalars and fermions. A locally approximated form of this equation detailing the structure of a generalized effective potential is numerically analyzed. The role of the irrelevant operators in the nonperturbative renormalization group running is elucidated and a comparison with the one-loop perturbative results is drawn. Focusing on the spontaneously broken phase of a model possessing a discrete symmetry forbidding an explicit fermion mass term, mass bounds on both the scalar and fermion degrees of freedom are established. The effect of the generalized Yukawa coupling on the scalar mass upper bound is emphasized.

Supersymmetry at finite temperature

Abstract Finite-temperature supersymmetry (SUSY) is characterized by unbroken Ward identifies for SUSY variations of ensemble averages of Klein-operator inserted imaginary time-ordered products of fields. Path-integral representations of these products are defined and the Feynman rules in superspace are given. The finite-temperature no-renormalization theorem is derived. Spontaneously broken SUSY at zero temperature is shown not to be restored at high temperature.

Effective action for brane localized gauge fields

The low energy effective action including gauge field degrees of freedom on a non-BPS p=2 brane embedded in a N=1, D=4 target superspace is obtained through the method of nonlinear realizations of the associated super-Poincare symmetries. The invariant interactions of the gauge fields and the brane excitation modes corresponding to the Nambu-Goldstone degrees of freedom resulting from the broken space translational symmetry and the target space supersymmetries are determined. Brane localized matter field interactions with the gauge fields are obtained through the construction of the combined gauge and super-Poincare covariant derivatives for the matter fields.

Nonlinear realization of supersymmetry and superconformal symmetry

Nonlinear realizations describing the spontaneous breakdown of supersymmetry and