A supersymmetric extension of the Weinberg-Salam model

By use of Slavnov's procedure, a supersymmetric extension of the Weinberg-Salam model of lepton interactions is obtained. At low energies (E ? m_W), that model is approached very closely. In addition, we get four heavy leptons (m?m_W) and a number of heavy scalars, plus a normally unobservable new neutrino.     

The supersymmetric one-dimensional string

We consider a supersymmetric discretized string. The full string theory is defined as the sum over the triangulations of the surface, which is imbedded in the superspace. In the continuum limit such a string theory is described by an appropriate Wess-Zumino model. We present an explicit computation of the properties of the string in the ID case: we find that supersymmetry is spontaneously broken.     

Massive supersymmetric quantum gauge theory

We continue the study of the supersymmetric vector multiplet in a purely quantum framework. We obtain some new results which make the connection with the standard literature. First we construct the one‐particle physical Hilbert space taking into account the (quantum) gauge structure of the model. Then we impose the condition of positivity for the scalar product only on the physical Hilbert space. Finally we obtain a full supersymmetric coupling which is gauge invariant in the supersymmetric sense in the first order of perturbation theory. By integrating out the Grassmann variables we get an interacting Lagrangian for a massive Yang‐Mills theory related to ordinary gauge theory; however the number of ghost fields is doubled so we do not obtain the same ghost couplings as in the standard model Lagrangian.     

Nonlinear supersymmetric standard model and its phenomenology

We consider the Higgs sector of a nonlinear supersymmetric standard model. Analytic solutions for some useful mass relations are derived. We investigate physical consequences of the model for LEP 1, LEP 2, and 500, 1000 resp. 2000 GeV LCs, and show that the neutral scalar Higgs bosons will most probably enable LC 500, 1000, 2000 to test the model conclusively, whereas at LEP 1, 2 only a part of the parameter space can be explored. As for the two pseudoscalar Higgs bosons the lighter one cannot be detected at any of the considered colliders, whereas the heavier one could possibly be detected with about “10 percent probability” at LC 1000 and LC 2000.     

Spontaneous supersymmetry breaking in supersymmetric string theories

A generalization of the dimensional reduction of supersymmetric string theories is introduced which leads to spontaneous breaking of supersymmetry. This supersymmetry breaking has non-trivial consequences for the quantization and dynamics of the theory. The lowest quantum correction to the cosmological constant is calculated and found to be unacceptably large.     

A supersymmetric extension of the standard model with bilinear R-parity violation

The minimum supersymmetric standard model with bilinear R-parity violation is studied systematically. As we consider low-energy supersymmetry, we examine the structure of the bilinear R-parity violating model carefully. We analyze the mixing of, e.g., Higgs bosons with sleptons, neutralinos with neutrinos and charginos with charged leptons in the model. Possible and some important physics results, e.g. that the lightest Higgs may be heavier than the weak Z-boson at tree level, are obtained. The Feynman rules for the model are derived in the 't Hooft–Feynman gauge, which is convenient if perturbative calculations are needed beyond the tree level. Received: 26 April 1999 / Revised version: 28 June 1999 / Published online: 16 November 1999     

New U(1) gauge extension of the supersymmetric standard model

In extending the minimal standard model of quarks and leptons to include supersymmetry, the conservation of baryon and lepton numbers is no longer automatic. I show how the latter may be achieved with a new U(1) gauge symmetry and new supermultiplets at the TeV scale. Neutrino masses and a solution of the mu problem are essential features of this proposed extension.     

Cosmic string configuration in the supersymmetric CSKR theory

We study a cosmic string solution of an (N=1)-supersymmetric version of the Cremmer–Scherk–Kalb–Ramond (CSKR) model coupled to scalars and fermions. The 2-form gauge potential is proposed to couple non-minimally to matter, here described by a chiral scalar superfield. The important outcome is that supersymmetry is kept exact in the core and it may also hold in the exterior region of the string. We contemplate the configurations of the bosonic sector and we check that the solutions saturate the Bogomol'nyi bound. A glimpse on the fermionic zero modes is also given.     

Covariant quantization of supersymmetric string theories: The spinor field of the Ramond-Neveu-Schwarz model

A brief review of superconformal field theory and superstrings is presented. The spacetime spinor contribution to the fermion vertex operator is constructed and the four-fermion amplitude is calculated using the differential equation method in the SO(1, 9) current algebra. The spinor field is also described as a vertex operator in the bosonization of the Ramond-Neveu-Schwarz fermions, and the two-cocycle for the fermion vertex is given.     

New supersymmetric extension of Poincaré algebra

A new supersymmetric extension of the poincaré algebra is given.     

A supersymmetric extension of the Kadomtsev-Petviashvili hierarchy

An extension of the Kadomtsev-Petviashvili hierarchy by odd variables is given. Conservation laws and formal integrability are proved.     

The heterotic string and the geometry of the supersymmetric Einstein-Yang-Mills background

It is shown that the Wess-Zumino term of a heterotic superstring in aN = 1,D = 10 supergravity background can be given in terms of the torsion of the background in both versions (IA and IB) of theN = 1,D = 10 supergravity theory. The gauge degrees of freedom of the background are included according to the ideas of Kaluza and Klein. Explicit expressions for the vielbein, connection, torsion, and curvature of a space with 506 bosonic and 16 fermionic coordinates are given.     

A locally supersymmetric and reparametrization invariant action for the spinning string

We construct an action for the spinning string which is locally supersymmetric and reparametrization invariant using the techniques of supergravity. In a special gauge it is shown that the equations of motion and the constraints are those of the Neveu-Schwarz-Ramond model.     

The heterotic string and supersymmetric counterparts of the Lorentz Chern-Simons terms

The heterotic string three-point amplitude, which involves two fermionic and one bosonic state, determines some of the terms that must be added to the action of the N=1 supergravity coupled to N=1 supersymmetric Yang-Mills in ten dimensions to preserve supersymmetry, if the Lorentz Chern-Simons term is included in the definition of the field strength H_μνϱ for the cancellation of anomalies. Our calculation reveals an interesting structure, which suggests that the relevant H-Bianchi for the analysis of possible heterotic string compactifications involves a spin connection possibly with torsion.     

Pseudo-supergravity extension of the bosonic string

We construct a “pseudo-supersymmetric” fermionic extension of the effective action of the bosonic string in arbitrary spacetime dimension D. The theory is invariant under pseudo-supersymmetry transformations up to the quadratic fermion order, which is sufficient in order to be able to derive Killing spinor equations in bosonic backgrounds, and hence to define BPS type solutions determined by a system of first-order equations. The pseudo-supersymmetric theory can be extended by coupling it to a Yang-Mills pseudo-supermultiplet. This also allows us to construct “α^′ corrections” involving quadratic curvature terms. An exponential dilaton potential term, associated with the conformal anomaly for a bosonic string outside its critical dimension, can also be pseudo-supersymmetrised.