One-loop adjoint masses for non-supersymmetric intersecting branes

TL;DR

This paper calculates the one-loop masses of adjoint scalars in non-supersymmetric intersecting D-brane setups, revealing tachyonic instabilities due to supersymmetry breaking effects from string theory and effective field theory perspectives.

Contribution

It provides a detailed computation of radiative corrections to adjoint scalar masses in intersecting branes with broken supersymmetry, linking string amplitudes to effective field theory.

Findings

Infrared contributions reproduce supersymmetry breaking mediation.

Ultraviolet contributions stem from uncanceled NS-NS tadpoles.

Leading order results indicate tachyonic directions in the spectrum.

Abstract

We consider breaking of supersymmetry in intersecting D-brane configurations by slight deviation of the angles from their supersymmetric values. We compute the masses generated by radiative corrections for the adjoint scalars on the brane world-volumes. In the open string channel, the string two-point function receives contributions only from the infrared and the ultraviolet limits. The latter is due to tree-level closed string uncanceled NS-NS tadpoles, which we explicitly reproduce from the effective Born-Infeld action. On the other hand, the infrared region reproduces the one-loop mediation of supersymmetry breaking in the effective gauge theory, via messengers and their Kaluza-Klein excitations. In the toroidal set-up considered here, it receives contributions only from broken N=4 and N=2 supersymmetric configurations, and thus always leads at leading order to a tachyonic direction, in agreement with effective field theory expectations.