Sleptonarium (Constraints on the CP and Flavour Pattern of Scalar Lepton Masses)

The constraints on the flavour and CP structure of scalar lepton mass matrices are systematically collected. The display of the resulting upper bounds on the lepton -slepton misalignment parameters is designed for an easy inspection of very large classes of models and the formula are arranged so as to suggest useful approximations. Interferences among the different contributions to lepton flavour violating transitions and lepton electric and magnetic dipole moments of generic character can either tighten or loose the bounds. A combined analysis of all rare leptonic transitions can disentangle the different contributions to yield hints on several phenomenological issues. The possible impact of these results on the study of the slepton misalignment originated in the seesaw mechanism and grand-unified theories is emphasized since the planned experiments are getting close to the precision required in such tests.Comment: 29 pages, 13 figures; v3: corrected misprints in appendix

Models with Inverse Sfermion Mass Hierarchy and Decoupling of the SUSY FCNC Effects

We study the decoupling of the first two squark and slepton families in order to lower the flavour changing neutral current effects. Models with inverse sfermion mass hierarchy based upon gauged U(1) flavour symmetries provide a natural framework where decoupling can be implemented. Decoupling requires a large gap between the Fermi scale and the supersymmetry breaking scale. Maintaining the electroweak symmetry breaking at the Fermi scale requires some fine-tuning that we investigate by solving the two-loop renormalization group equations. We show that the two-loop effects are governed by the anomaly compensated by the Green-Schwarz mechanism and can be determined from the quark and lepton masses. The electroweak breaking constraints lead to a small $\mu$ scenario where the LSP is Higgsino-like.Comment: 19 pages, Latex, 1 Postscript figur

Supersymmetric Flat Directions and Analytic Gauge Invariants

We review some aspects of the correspondence between analytic gauge invariants and supersymmetric flat directions for vanishing D-terms and propose a criterion to include the F-term constraints.Comment: 8 pages, Late

Geometrical approach to duality in N=1 supersymmetric theories

We investigate the geometry of the moduli spaces of dual electric and magnetic N=1 supersymmetric field theories. Using the SU(N_c) gauge group as a guideline we show that the electric and magnetic moduli spaces coincide for a suitable choice of the Kahler potential of the magnetic theory. We analyse the Kahler structure of the dual moduli spaces.Comment: 14 pages, LaTe

Intermediate Symmetries in the Spontaneous Breaking of Supersymmetric SO(10)

We study the supersymmetric spontaneous symmetry breaking of SO(10) into SU(3)xSU(2)xU(1) for the most physically interesting cases of SU(5) or flipped SU(5)xU(1) intermediate symmetries. The first case is more easily realized while the second one requires a fine-tuning condition on the parameters of the superpotential. This is because in the case of SU(5) symmetry there is at most one singlet of the residual symmetry in each SO(10) irreducible representation. We also point out on more general grounds in supersymmetric GUT's that some intermediate symmetries can be exactly realized and others can only be approximated by fine-tuning. In the first category, there could occur some tunneling between the vacua with exact and approximate intermediate symmetry. The flipped SU(5)xU(1) symmetry improves the unification of gauge couplings if (B-L) is broken by (B-L)=1 scalars yielding right handed neutrino masses below 10^{14} GeV}.Comment: LaTex, 9 page

Chiral Extensions of the MSSM

We present a class of extensions of the MSSM characterized by a fully chiral field content (no mu-terms) and no baryon or lepton number violating term in the superpotential due to an extra U'(1) gauge symmetry. The minimal model consist of the usual matter sector with family dependent U'(1) charges, six Higgs weak doublets, and three singlets required to give masses to the Higgsinos and cancel anomalies. We discuss its main features such as the tree level mass spectrum and the constraints on flavor changing processes.Comment: 13 pages. V2: Superpotential and U'(1) charges changed. Analysis of the spectrum for the new model added. References update

Quark flavour conserving violations of the lepton number

We study supersymmetric models of lepton and baryon number violation based on an abelian family gauge group. Due to possible lepton-Higgs mixing, the lepton violating couplings are related to the Yukawa couplings and may be generated by them even if they were absent in the original theory. Such terms may be dominant and are not given by the naive family charge counting rules. This enhancement mechanism can provide an alignment between lepton-number violating terms and Yukawa couplings: as a result they conserve quark flavour. A natural way of suppressing baryon number violation in this class of models is also proposed