Dynamical mass generation for the gravitino in N = 1 supergravity

The Volkov-Akulov field is coupled to supergravity and it is gauged away through a field redefinition, remaining with a negative cosmological constant plus N = 1 supergravity lagrangian. Then the gravitino sector is quantized and a positive cosmological constant is obtained along with a mass-like term for the gravitino. Imposing the effective cosmological constant to be zero, consequently a genuine mass term for the gravitino is obtained. The corresponding energy-gap equation shows that this mass turns out to be of the order of the Planck mass.     

N=1 Dilatation supergravity

The geometrical aspect of theN=1 dilatation supergravity is here studied from the point of view of the internal structure of matter. It is shown thatN=1 supergravity may be taken to have arisen from the internal helicity of hadrons and gives rise to a torsion term in the gravitational action. This formalism is found to be in conformity with the chiral formalism of superfield developed by other authors.     

Correlations between Gaugino and Sfermion masses in N=1 supergravity models

It is demonstrated that the observation of a light wino or zino together with an intermediate mass photino implies strong lower bounds for squark and slepton masses in the framework of minimal N=1 supergravity models. These bounds turn out to be even more restrictive within the recently proposed superstring motivated SU (5) model.     

Hierarchy of quark masses in the isotopic doublets in N=1 supergravity models

In the framework of some generic softly broken SUSY models we study the SU (2) × U(1) breaking by radiative corrections, starting with the Yukawa couplings which at the Planck scale M_P satisfy h^t = h^b. Physically acceptable solutions exist with the heirarchy of VEVs: ν₂/ν₁ ≈ m_t/m_b provided m_t ⩾ 50 GeV. When the SUSY breaking is driven only by the gaugino mass the solutions uniquely predict ν₂=O(10)ν₁ and the top mass in the range 50–65 GeV. Also, the mass ratio in the second quark generation can be accounted for.     

Bianchi V models in N=2, D=5 supergravity

We investigate Bianchi V cosmological models containing two interacting scalar fields. These models are derived from a dimensional reduction of theN=2,D=5 supergravity theory. Exact solutions are found.     

Super-Higgs effect in N = 1 non-minimal supergravity

The component form of the lagrangian of 20 + 20 supergravity coupled to a chiral matter field is derived. The scalar potential is shown to be different from the old-minimal Kähler-invariant form. It is demonstrated that spontaneous supersymmetry breaking occurs, and that the mass formula of the old-minimal theory in general is not valid.     

Superstring effects on D=4, N=1 supergravity

We give a lagrangian and supersymmetry transformation rules for the four-dimensional N=1 supergravity sector of superstring theories with their O(α′) corrections, obtained by the dimensional reduction á la Witten of the effective action of the ten-dimensional heterotic superstring. We also give general forms of O(α′ ″) corrections to supersymmetry transformation rules which arise through an axial vector superfield. Since our system is based on the ten-dimensional superstring without any auxiliary fields, our four-dimensional N=1 supergravity is free of auxiliary fields. Our point-field theory lagrangian is supposed to describe the mass-less fields in the untwisted sector of the ten-dimensional heterotic superstring propagating on orbifolds.     

Bianchi VI0 models in N=2, D=5 supergravity

We investigate Bianchi VI₀ cosmological models containing two interacting scalar fields. These models are derived from a dimensional reduction of theN=2,D=5 supergravity theory. Exact solutions are found and the existence of singularities for them is considered.     

Superspace geometry and N = 1 non-minimal supergravity

We investigate superspace geometry for supergravity with non-minimal auxilliary fields. We find that the kinematic constraints and the superspace Bianchi identities are sufficient to obtain complete component expansions of all superspace quantities, including the vielbein and connection superfields. We include a detailed pedagogical discussion on the analysis of constrained superspace Bianchi identities, demonstrating how these are used to derive component field content and transformation laws. We also note that local, chiral supersymmetry representations which form arbitrary representations of the Lorentz group can exist only within the context of supergravity with non-minimal auxilliary fields.     

Neutrino radiative decay in N=1 supergravity theories

We show that the supersymmetrization of models where neutrinos acquire mass through the see-saw mechanism allows for tau neutrinos heavier than 15–20 MeV to decay radiatively in a cosmologically safe way (i.e. with a lifetime τ_v⩽5×10³s).     

N = 3 and N = 1 supersymmetry in a new class of solutions for d = 11 supergravity

We present a new class of compactifying solutions for d = 11 supergravity. The internal 7-spaces are described by coset manifolds N^pqr of the form SU(3) × U(1)/U(1) × U(1). The three integers p, q, r characterize the embedding of the stability subgroup U(1) × U(1) in SU(3) × U(1).Their supersymmetry content is quite remarkable. For a particular choice of p, q, r the isometry of N^pqr is SU(3) × SU(2): in this case we find that N = 3 supersymmetry survives. For all the other values of p, q, r, supersymmetry is broken to N = 1, and the isometry group is SU(3) × U(1).We also find a class of solutions with internal photon curl F_αβγδ ≠ 0, breaking all supersymmetries.     

The anomaly cancellation mechanism in N=1, D=4 supergravity and distorted supergravity algebra with Chern-Simon forms

A mechanism is exhibited which ensures that N=1, D=4 new minimal supergravity is free of Lorentz×U(1) anomalies, for any coupling to matter, although it contains an abelian chiral gauge field. This is achieved through the determination of a new supergravity algebra characterized by the presence of a U(1)×Lorentz Chern-Simon form in the field strength of a two-form gauge field. Our analysis provides therefore an example in which Chern-Simon type interactions do occur, while preserving local supersymmetry.     

The Cauchy problem in extended supergravity,N=1,d=11

We prove the Grassmann valued system of extended supergravityN=1,d=11 proposed by Cremmer and Julia is well proposed and causal.     

Off-shell BRS-invariant construction of N = 1, D = 4 conformal supergravity

A geometrical construction is displayed of the BRS structure of the N = 1, D = 4 conformal supergravity theory. The requirement of a nilpotent differential structure determines directly the closure of the conformal supergravity transformation laws. All existing geometrical constraints between field strengths are systematically worked out from the requirement of Bianchi identities. As a by-product of the technics involved, some new features of conformal gravity are revealed.