Twisted Moduli and Supersymmetry Breaking

We consider twisted moduli contributions to supersymmetry breaking ineffective type I string constructions involving intersecting D5_i and D9-branesusing Goldstino angles to parametrise the supersymmetry breaking. It is wellknown that twisted moduli enter at tree-level into the gauge kinetic functions,and can provide new sources of gaugino mass if they develop F-term vacuumexpectation values. It is generally assumed that string states which aresequestered from the twisted moduli receive a zero soft mass in the twistedmodulus domination limit, however the standard form of Kahler potential doesnot reproduce this expectation. We therefore propose a new form of the Kahlerpotential which is consistent at leading order with the sequestered formproposed by Randall and Sundrum, and show that it leads to exponentiallysuppressed sequestered soft masses. Including the effects of Green-Schwarzmixing, we write down the soft scalar masses and trilinears arising from a typeI string construction involving intersecting D5_i and D9-branes in the presenceof untwisted and twisted moduli. If the squarks and sleptons are identifiedwith sequestered states then in the twisted moduli dominated limit thiscorresponds to gaugino mediated supersymmetry breaking, and we discuss twodifferent scenarios for this. The general results will be useful forphenomenological studies involving a combination of gravity and gauginomediated SUSY breaking due to the dilaton, untwisted and twisted modulicontributions, and enable the soft masses to be studied as a function of thedifferent compactification radii.Comment: Additional appendix generalises results for alternative exponential suppression factor. Version accepted for publicaton in JHE