Non-linear supersymmetry and intersecting D-branes

TL;DR

This paper explores the non-linear realization of supersymmetry, classifies effective operators involving the Goldstino, and computes their coefficients in string models with intersecting D-branes, revealing universal and model-dependent features.

Contribution

It provides a comprehensive classification of Goldstino interactions and calculates their coefficients in string models with intersecting D-branes, highlighting universal and model-dependent aspects.

Findings

Universal coupling to energy momentum tensor of dimension eight.

Presence of lower-dimensional operators, starting from dimension six.

Goldstino decay constant equals total brane tension.

Abstract

We study the non-linear realization of supersymmetry. We classify all lower dimensional operators, describing effective interactions of the Goldstino with Standard Model fields. Besides a universal coupling to the energy momentum tensor of dimension eight, there are additional model dependent operators whose strength is not determined by non-linear supersymmetry, within the effective field theory. Their dimensionality can be lower than eight, starting with dimension six, leading in general to dominant effects at low energies. We compute their coefficients in string models with D-branes at angles. We find that the Goldstino decay constant is given by the total brane tension, while the various dimensionless couplings are independent from the values of the intersection angles.