Pattern Of Soft Terms Research Articles

Flux-induced SUSY-breaking soft terms

We describe the computation of SUSY-breaking terms on a D3-brane in a quite general type IIB supergravity background. We apply it to study the SUSY-breaking induced on the D3-brane worldvolume by the presence of NSNS and RR 3-form fluxes. We provide explicit general formulae for the SUSY-breaking soft terms valid for the different types of fluxes, leading to different patterns of soft terms. Imaginary anti-self-dual fluxes with G 3 a pure (3,0)-form lead to soft terms corresponding to dilaton-dominated SUSY-breaking. More general SUSY-breaking patterns are discussed, arising from more general fluxes, or from distant anti-D3-branes. The known finiteness properties of dilaton-dominated soft terms are understood in terms of holography. The above results are interpreted in the context of the 4d effective supergravity theory, where flux components correspond to auxiliary fields of, e.g., the 4d dilaton and overall volume modulus. We present semirealistic type IIB orientifold examples with (meta)stable vacua leading to non-vanishing soft terms of the dilaton-domination type. Such models have many of the ingredients of the recent construction of de Sitter vacua in string theory. We finally explore possible phenomenological applications of this form of SUSY-breaking, where we show that soft terms are of order M s 2/ M p . Thus a string scale of order M s =10 10 GeV, and compactification scale three orders of magnitude smaller could explain the smallness of the weak scale versus the Planck mass.

Flux-induced SUSY-breaking soft terms

We describe the computation of SUSY-breaking terms on a D3-brane in a quite general type IIB supergravity background. We apply it to study the SUSY-breaking induced on the D3-brane worldvolume by the presence of NSNS and RR 3-form fluxes. We provide explicit general formulae for the SUSY-breaking soft terms valid for the different types of fluxes, leading to different patterns of soft terms. Imaginary anti-self-dual fluxes with G3 a pure (3,0)-form lead to soft terms corresponding to dilaton-dominated SUSY-breaking. More general SUSY-breaking patterns are discussed, arising from more general fluxes, or from distant anti-D3-branes. The known finiteness properties of dilaton-dominated soft terms are understood in terms of holography. The above results are interpreted in the context of the 4d effective supergravity theory, where flux components correspond to auxiliary fields of, e.g., the 4d dilaton and overall volume modulus. We present semirealistic type IIB orientifold examples with (meta)stable vacua leading to non-vanishing soft terms of the dilaton-domination type. Such models have many of the ingredients of the recent construction of de Sitter vacua in string theory. We finally explore possible phenomenological applications of this form of SUSY-breaking, where we show that soft terms are of order Ms2/Mp. Thus a string scale of order Ms=1010 GeV, and compactification scale three orders of magnitude smaller could explain the smallness of the weak scale versus the Planck mass.

Some issues in soft SUSY-breaking terms from dilaton∣moduli sectors

We study the structure of the soft SUSY-breaking terms obtained from some classes of 4-D strings under the assumption of dilaton/moduli dominance in the process of SUSY-breaking. We generalize previous analyses in several ways and in particular consider the new features appearing when several moduli fields contribute to SUSY breaking (instead of an overall modulus T ). Some qualitative features indeed change in the multimoduli case. A general discussion for symmetric Abelian orbifolds as well as explicit examples are given. Certain general sumrules involving soft terms of different particles are shown to apply to large classes of models. Unlike in the overall modulus T case, gauginos may be lighter than scalars even at the tree-level. However, if one insists in getting that pattern of soft terms, these sum rules force some of the scalars to get negative mass2. These tachyonic masses could be a problem for standard model 4-D strings but an advantage in the case of string-GUTs. We also discuss the possible effects of off-diagonal metrics for the matter fields which may give rise to flavour-changing neutral currents. Different sources for the bilinear B soft term are studied. It is found that the Giudice-Masiero mechanism for generating a “μ-term”, as naturally implemented in orbifolds, leads to the prediction ¦tgβ¦=1 at the string scale, independently of the Goldstino direction.