Related papers: Modular Invariance, Soft Breaking, $\mu$ and $\tan…
There are at least two serious moduli problems in string cosmology. The first is the possibility that moduli dominate the energy density at the time of nucleosynthesis. The second is that they may not find their minima all together. After…
Motivated from unified models with string origin, we analyse the constraints from duality invariance on effective supergravity models with an intermediate gauge symmetry. Requiring vanishing vacuum energy and invariance of the…
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 consider the low energy description of five dimensional models of supergravity with boundaries comprising a vector multiplet and the universal hypermultiplet in the bulk. We analyse the spontaneous breaking of supersymmetry induced by…
We study the muon anomalous magnetic moment a_\mu = (g_\mu - 2)/2 in a supersymmetric U(1)' model. The neutralino sector has extra components from the superpartners of the U(1)' gauge boson and the extra Higgs singlets that break the U(1)'…
We study dynamical gaugino condensation in superstring effective theories using the linear multiplet representation for the dilaton superfield. An interesting necessary condition for the dilaton to be stabilized, which was first derived in…
We study moduli-dominated SUSY breaking within the framework of string models. This type of SUSY breaking in general leads to non-universal soft masses, i.e. soft scalar masses and gaugino masses. Further gauginos are lighter than…
Supersymmetric heterotic string models, built from a stable holomorphic vector bundle $V$ on a Calabi-Yau threefold $X$, usually come with many vector bundle moduli whose stabilisation is a difficult and complex task. It is therefore of…
We report on how a straightforward (albeit technically involved) analytic study of the 1-loop effective potential in the Minimal Supersymmetric Standard Model, modifies the usual electroweak symmetry breaking conditions involving $\tan…
There has been much discussion in the literature about applying the radiative electroweak symmetry breaking (EWSB) requirement to GUT models with supergravity. We motivate and discuss the application of the EWSB requirement to the low…
We perform a systematic analysis of soft supersymmetry breaking terms at the one loop level in a large class of string effective field theories. This includes the so-called anomaly mediated contributions. We illustrate our results for…
The crucial problem of how the dilaton field is stabilized at a phenomenologically acceptable value in string theories remains essentially unsolved. We show that the usual scenario of assuming that the dilaton is fixed by the (SUSY…
The possibility of dynamical electroweak symmetry breaking by strong coupling gauge interaction in models with D-branes in String Theory is examined. Instead of elementary scalar Higgs doublet fields, the gauge symmetry with strong coupling…
We demonstrate that supergravity models containing the Standard Model, dilaton and modulus naturally lead to dynamical symmetry breaking with excellent phenomenology. We assume primordial supersymmetry breaking in the form of a constant…
We consider a class of well motivated string-inspired flipped $SU(5)$ supergravity models which include four supersymmetry breaking scenarios: no-scale, strict no-scale, dilaton, and special dilaton, such that only three parameters are…
We derive general expressions for soft terms in supergravity where D-terms contribute significantly to the supersymmetry breaking. Such D-terms can produce large splitting between scalar and fermionic partners in the spectrum. By requiring…
We investigate the possibility of large CP- violating phases in the soft breaking terms derived in superstring models. The bounds on the electric dipole moments (EDM's) of the electron and neutron are satisfied through cancellations…
We lay out a novel formalism to connect the isospin-symmetry breaking correction to the rates of superallowed nuclear beta decays, $\delta_\text{C}$, to the isospin-breaking sensitive combinations of electroweak nuclear radii that can be…
Motivated by the recently measured muon's anomalous magnetic moment $a_{\mu}$, we examine the supersymmetry contribution to $a_{\mu}$ in various mediation models of supersymmetry breaking which lead to predictive flavor conserving soft…
We analyze the perturbative stability of non-supersymmetric intersecting brane world models on tori. Besides the dilaton tadpole, a dynamical instability in the complex structure moduli space occurs at string disc level, which drives the…