Dynamical Determination of the Fundamental Couplings in Supergravity Models

2015

We present a qualitatively new mechanism for dynamical spontaneous breakdown of supersymmetry in supergravity. Specifically, we construct a modified formulation of standard minimal N=1 supergravity as well as of anti-de Sitter supergravity in terms of a non-Riemannian spacetime volume-form (generally covariant integration measure density). The new supergravity formalism naturally triggers the appearance of a dynamically generated cosmological constant as an arbitrary integration constant which signifies spontaneous (dynamical) breaking of supersymmetry. Applying the new formalism to anti-de Sitter supergravity allows us to appropriately choose the above mentioned arbitrary integration constant so as to obtain simultaneously a very small effective observable cosmological constant as well as a large physical gravitino mass as required by modern cosmological scenarios for slowly expanding universe of the present epoch.

Physical Review D, 1992

It is shown that spontaneous breaking of supersymmetry without a cosmological constant is impossible in the context of new minimal supergravity.

2018

Some general aspects of supersymmetry and supergravity are briefly reviewed with emphasis on Noether supercurrents and their role in the discussion of supersymmetry breaking. Contribution to the Proceedings of the Erice International School of Subnuclear Physics, 56th Course: “From gravitational waves to QED, QFD and QCD” Erice, 14-23 June 2018 e-mails: Sergio.Ferrara@cern.ch, magnus.tournoy@kuleuven.be ar X iv :1 81 1. 09 45 0v 2 [ he pth ] 3 0 N ov 2 01 8

Fortschritte der Physik, 2008

We study the conditions under which a generic supergravity model involving chiral and vector multiplets can admit vacua with spontaneously broken supersymmetry and realistic cosmological constant. We find that the existence of such viable vacua implies some constraints involving the curvature tensor of the scalar geometry and the charge and mass matrices of the vector fields, and also that the vector of F and D auxiliary fields defining the Goldstino direction is constrained to lie within a certain domain. We illustrate the relevance of these results through some examples and also discuss the implications of our general results on the dynamics of moduli fields in string models. This contribution is based on [1–3].

1997

We review the origin of soft supersymmetry-breaking terms in N = 1 supergravity models of particle physics. We first consider general formulae for those terms in general models with a hidden sector breaking supersymmetry at an intermediate energy scale. The results for some simple models are given. We then consider the results obtained in some simple superstring models in which particular assumptions about the origin of supersymmetry breaking are made. These are models in which the seed of supersymmetry breaking is assumed to be originated in the dilaton/moduli sector of the theory.

Nuclear Physics B, 1996

We construct two classes of higher-derivative supergravity theories generalizing Einstein supergravity. We explore their dynamical content as well as their vacuum structure. The first class is found to be equivalent to Einstein supergravity coupled to a single chiral superfield. It has a unique stable vacuum solution except in a special case, when it becomes identical to a simple no-scale theory. The second class is found to be equivalent to Einstein supergravity coupled to two chiral superfields and has a richer vacuum structure. It is demonstrated that theories of the second class can possess a stable vacuum with vanishing cosmological constant that spontaneously breaks supersymmetry. We present an explicit example of this phenomenon and compare the result with the Polonyi model.

Physics Letters B, 2000

We analyze simple models of gauge mediated supersymmetry breaking in the context of supergravity. We distinguish two cases. One is when the messenger of the supersymmetry breaking is a non Abelian gauge force and the other is when the messenger is a pseudoanomalous U(1). We assume that these models originate from string theory and we impose the constraint of the vanishing of the cosmological constant requiring also the stabilization of the dilaton. In the first case, we do not find vacua that are consistent with the constraints of gauge mediation and have a zero tree level cosmological constant. In the second case, no such conflict arises. In addition, by looking at the one loop cosmological constant, we show that the dilaton F -term can not be neglected in either case. For the gauge mediated case our considerations suggest that the dilaton must be frozen out of the low energy field theory by non-perturbative string dynamics.

arXiv (Cornell University), 1994

We revisit the no-scale mechanism in the context of the simplest no-scale supergravity extension of the Standard Model. This model has the usual five-dimensional parameter space plus an additional parameter ξ 3/2 ≡ m 3/2 /m 1/2. We show how predictions of the model may be extracted over the whole parameter space. A necessary condition for the potential to be stable is StrM 4 > 0, which is satisfied if m 3/2 < ∼ 2mq. Order of magnitude calculations reveal a no-lose theorem guaranteeing interesting and potentially observable new phenomena in the neutral scalar sector of the theory which would constitute a "smoking gun" of the no-scale mechanism. This new phenomenology is model-independent and divides into three scenarios, depending on the ratio of the weak scale to the vev at the minimum of the no-scale direction. We also calculate the residual vacuum energy at the unification scale (C 0 m 4 3/2), and find that in typical models one must require C 0 > 10. Such constraints should be important in the search for the correct string no-scale supergravity model. We also show how specific classes of string models fit within this framework.

Modern Physics Letters A, 1999

In this work we have constructed the most general action for a set of complex homogeneous scalar supermultiplets interacting with the scale factor in the supersymmetric FRW model. It is shown that the local conformal time supersymmetry leads to a scalar field potential defined in terms of the Kahler potential and superpotential in the same combination as in supergravity (or effective superstring) theories. This scalar field potential depends on an arbitrary parameter Q which is not fixed by conformal time supersymmetry and induces the spontaneous breaking of supersymmetry in supergravity theories.

Modern Physics Letters A, 2003

We consider the interplay of duality symmetries and gauged isometries of supergravity models giving N-extended, spontaneously broken supergravity with a no-scale structure. Some examples motivated by superstring and M-theory compactifications are described.