Supersymmetric codimension-two branes and U(1)_R mediation in 6D gauged supergravity

TL;DR

This paper develops a supersymmetric framework for branes in 6D supergravity, exploring how brane tensions and U(1)_R interactions influence moduli stabilization and soft mass generation in 4D effective theories.

Contribution

It presents a consistent supersymmetric action for branes in 6D supergravity with novel brane-localized FI terms and analyzes their implications for 4D moduli stabilization and soft mass generation.

Findings

Moduli are stabilized with zero cosmological constant using gaugino condensates and brane F/D-terms.

Brane scalar with R charge acquires soft mass proportional to the gravitino mass.

Sign of soft mass squared depends on R charge and dominant brane F- or D-term.

Abstract

We construct a consistent supersymmetric action for brane chiral and vector multiplets in a six-dimensional chiral gauged supergravity. A nonzero brane tension can be accommodated by allowing for a brane-localized Fayet-Iliopoulos term proportional to the brane tension. When the brane chiral multiplet is charged under the bulk U(1)_R, we obtain a nontrivial coupling to the extra component of the U(1)_R gauge field strength as well as a singular scalar self-interaction term. Dimensionally reducing to 4D on a football supersymmetric solution, we discuss the implication of such interactions for obtaining the U(1)_R D-term in the 4D effective supergravity. By assuming the bulk gaugino condensates and nonzero brane F- and/or D-term for the uplifting potential, we have all the moduli stabilized with a vanishing cosmological constant. The brane scalar with nonzero R charge then gets a soft mass of order the gravitino mass. The overall sign of the soft mass squared depends on the sign of the R charge as well as whether the brane F- or D-term dominates.