Related papers: Soft SUSY Breaking, Dilaton Domination and Interme…
We study the magnitudes of soft SUSY breaking parameters in heterotic string models with anomalous U(1) symmetry. In most cases, D-term contribution to soft scalar masses is expected to be comparable to or dominant over other contributions…
I consider the superfield derivation of the effective theory of softly broken supersymmetry below the GUT scale. I point out the role of supergauge invariance in determining the form of the result, which is rather restricted in interesting…
In minimal supergravity theories the soft supersymmetry breaking (SSB) parameters are universal (flavor blind) near the Planck scale. Nevertheless, one often assumes universality at the grand-unification scale $M_{G} \approx 10^{16}$ GeV…
Gauge-mediated SUSY breaking with a messenger scale of order $10^{15}$ GeV has some interesting features. It can solve the flavor changing neutral current problem of supersymmetric models with predictions for superpartner masses which are…
We study the fine tuning associated to a `Natural Supersymmetry' spectrum with stops, after RG running, significantly lighter than the first two generation sfermions and the gluino. In particular, we emphasise that this tuning should be…
We comment on aspects of discrete anomaly conditions focussing particularly on $R$ symmetries. We review the Green-Schwarz cancellation of discrete anomalies, providing a heuristic explanation why, in the heterotic string, only the…
In the context of the standard SUSY GUT scenario, we present a detailed analysis of the softly broken finite supersymmetric grand unified theory. The model, albeit non-minimal, remains very rigid due to the requirement of finiteness. It is…
We study the phenomenological implications of effective supergravities based on string vacua with spontaneously broken N=1 supersymmetry by dilaton and moduli $F$-terms. We further require Minimal String Unification, namely that large…
We analyze the constraints that a correct phenomenology and the absence of dangerous charge and color breaking (CCB) minima or unbounded from below (UFB) directions impose on the parameter space of different superstring and M-theory…
It is shown that non-renormalizable gravitational interactions in the Higgs sector of supersymmetric grand unified theories (GUT's) can produce the breaking of the unifying gauge group $G$ at the GUT scale $M_{\rm GUT} \sim 10^{16}$~GeV.…
We address intermediate scales within a class of string models. The intermediate scales occur due to the SM singlets S_i acquiring non-zero VEVs due to radiative breaking; the mass-square (m_i)^2 of S_i is driven negative at mu_{RAD} due to…
We present a dilaton dominated scenario for supersymmetry breaking in a recently constructed realistic superstring inspired model with an anomalous U(1) symmetry. Supersymmetry is broken via gaugino condensation due to a confining SU(Nc)…
We present an overview of the simplest supergravity models which enforce radiative breaking of the electroweak symmetry, namely the minimal $SU(5)$ supergravity model and the class of string-inspired/derived supergravity models based on the…
We study in a systematic and modular invariant way gaugino condensation in the hidden sector as a potential source of hierarchical supersymmetry breaking and a non--trivial potential for the dilaton $S$ whose real part corresponds to the…
The phenomenology associated with gauge-mediated supersymmetry breaking is presented. A renormalization group analysis of the minimal model is performed in which the constraints of radiative electroweak symmetry breaking are imposed. The…
SO(10) supersymmetric grand unified theories [SUSY GUTs] provide a beautiful framework for physics beyond the standard model. Experimental measurements of the three gauge couplings are consistent with unification at a scale $M_G \sim 3…
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…
In the GmSUGRA scenario with the high-dimensional operators containing the GUT Higgs fields, we systematically studied the supersymmetry breaking scalar masses, SM fermion Yukawa coupling terms, and trilinear soft terms in the E_6 SUSY GUT…
We construct a comprehensive list of non-supersymmetric standard model extensions with a low-scale LR-symmetric intermediate stage that may be obtained as simple low-energy effective theories within a class of renormalizable $SO(10)$ GUTs.…
We propose that gaugino condensation in the hidden sector may dynamically induce intermediate gauge symmetry breaking and specify the compactification scale. We also show that this scheme makes possible affine level one grand unified string…