Anomaly Mediation in Superstring Theory

TL;DR

This paper investigates anomaly mediated supersymmetry breaking within type IIB string theory, calculating gaugino masses via string amplitudes and testing supergravity predictions, revealing both matches and ambiguities.

Contribution

It provides the first detailed string-theoretic calculation of anomaly mediated gaugino masses, confirming supergravity formulas for certain flux backgrounds and exploring UV contributions.

Findings

Exact match with supergravity for NS-NS flux

Off-shell ambiguity in R-R flux case

Explicit string calculation of UV winding mode contributions

Abstract

We study anomaly mediated supersymmetry breaking in type IIB string theory and use our results to test the supergravity formula for anomaly mediated gaugino masses. We compute 1-loop gaugino masses for models of D3-branes on orbifold singularities with 3-form fluxes by calculating the annulus correlator of 3-form flux and two gauginos in the zero momentum limit. Consistent with supergravity expectations we find both anomalous and running contributions to 1-loop gaugino masses. For background Neveu-Schwarz H-flux we find an exact match with the supergravity formula. For Ramond-Ramond flux there is an off-shell ambiguity that precludes a full matching. The anomaly mediated gaugino masses, while determined by the infrared spectrum, arise from an explicit sum over UV open string winding modes. We also calculate brane-to-brane tree-level gravity mediated gaugino masses and show that there are two contributions coming from the dilaton and from the twisted modes, which are suppressed by the full T^6 volume and the untwisted T^2 volume respectively.