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=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.     

Radiative corrections to the effective potential inN=1 supergravity

We compute the one loop quadratic divergences to the effective potential of the matter scalars inN=1 supergravity. We discuss in some special instances (the Das-Freedman and the Deser-Zumino Lagrangians) the problem of supersymmetry gauge invariance. We comment on the relevance of the calculation to model building.     

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.     

Renormalization of N = 1 supersymmetric Yang-Mills theories: (II). The radiative corrections

We give a general proof of ultraviolet renormalizability relying on the methods of BRS and find that no anomaly can occur if the gauge group is assumed to be semisimple. We derive the Callan-Symanzik equation.     

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.     

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.     

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.     

Bounds on the top-quark mass in N=1 supergravity models

From the tree level study of the SU(3)×SU(2)×U(1) model arising as the flat limit of a spontaneously broken N=1 supergravity, via the super Higgs mechanism, we find particular directions of minima which lead to upper bound for the top-quark mass. These bounds on m_t can also be of relevance to superstring-inspired low-energy models.     

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.     

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.     

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.     

The integrability of N=16 supergravity

For the maximally extended N=16 supergravity theory in two dimensions, we explicitly construct a linear system whose integrability conditions are equivalent to the full nonlinear field equations of this theory. All the (on-shell) information contained in it can thus be encoded into a single E₈ matrix and its dependence on a spectral parameter; the invariance of the equations of motion under E₉ is manifest. Possible consequences and further developments are briefly discussed.     

Gauged N = 8 supergravity in five dimensions

We construct gauged N = 8 supergravity theories in five dimensions. Instead of the twenty-seven vector fields of the ungauged theory, the gauged theories contain fifteen vector fields and twelve second-rank antisymmetric tensor fields satisfying self-dual field equations. The fifteen vector fields can be used to gauge any of the fifteen-dimensional semisimple subgroups of SL(6,R), specially SO(p, 6?p) for p = 0, 1, 2, 3. The gauged theories also have a physical global SU(1,1) symmetry which survives from the E₆₍₆₎ symmetry of the ungauged theory. This SU(1,1) for the SO(6) gauging is presumably related to that of the chiral N = 2 theory in ten dimensions. In our formalism we maintain a composite local USp(8) symmetry analogous to SU(8) in four dimensions.