Hidden Sector Supergravity Breakdown

Gravity mediated supersymmetry breakdown originated from a study of gaugino condensation in a hidden sector. We review this mechanism of supergravity breakdown from the original formulation in the early eighties to its natural implementation in superstring theory and M-theory. In the latter case hidden and observable sector become separated geometrically and supersymmetry is broken dynamically on a hidden wall.Comment: 14 pages, Latex, Invited talk presented at the symposium "Thirty Years of Supersymmetry", University of Minnesota, October 13-15, 200

M-branes at angles

Supersymmetric configurations of non-orthogonally intersecting M-5-branes can be obtained by rotation of one of a pair of parallel M-5-branes. Examples preserving 1/4, 3/16 and 1/8 supersymmetry are reviewed.Comment: 5pp Latex. To appear in proceedings of 1997 Trieste conference on "Duality Symmetries in String Theory - II". Minor correction

The Status of the Minimal Supersymmetric Standard Model and Beyond

The minimal supersymmetric extension of the Standard Model (MSSM) is reviewed. In the most general framework with minimal field content and R-parity conservation, the MSSM is a 124-parameter model (henceforth called MSSM-124). An acceptable phenomenology occurs only at exceptional points (and small perturbations around these points) of MSSM-124 parameter space. Among the topics addressed in this review are: gauge coupling unification, precision electroweak data, phenomenology of the MSSM Higgs sector, and supersymmetry searches at present and future colliders. The implications of approaches beyond the MSSM are briefly addressed.Comment: 17 pages, LaTeX, with espcrc2.sty style file, to appear in the Proceedings of the 5th International Conference on Supersymmetries in Physics (SUSY 97

Supersymmetry breaking in M-theory

We describe the breaking of supersymmetry in M-theory by coordinate dependent (Scherk-Schwarz) compactification of the eleventh dimension. Supersymmetry is spontaneously broken in the gravitational and moduli sector and communicated to the observable sector, living at the end-point of the semicircle, by radiative gravitational interactions. This mechanism shares the generic features of non-perturbative supersymmetry breaking by gaugino condensation, in the presence of a constant antisymmetric field strength, in the weakly coupled regime of the heterotic string, which suggests that both mechanisms could be related by duality. In particular an analysis of supersymmetric transformations in the infinite-radius limit reveals the presence of a discontinuity in the spinorial parameter, which coincides with the result found in the presence of gaugino condensation, while the condensate is identified with the quantized parameter entering the boundary conditionsComment: 10 pages, latex + espcrc2.sty, no figures. Based on talks given at the 5th International Conference on Supersymmetries in Physics, SUSY 97, May 27-31, 1997, University of Pennsylvania, Philadelphia, PA; and, International Europhysics Conference on High Energy Physics, HEP 97, 19-26 August, Jerusalem, Israe

Flat Higgs Potential from Planck Scale Supersymmetry Breaking

The observed Higgs boson mass poses a new puzzle in addition to the longstanding problem of the origin of the electroweak scale; the shallowness of the Higgs potential. The Higgs quartic coupling even seems to vanish at around the Planck scale within the uncertainties of the top quark mass and the strong gauge coupling. We show that the shallowness of the Higgs potential might be an outcome of supersymmetry breaking at around the Planck scale. There, the electroweak fine-tuning in the Higgs quadratic terms leads to an almost vanishing quartic coupling at around the Planck scale.Comment: 4 pages, 2 figure