Goldstino and sgoldstino in microscopic models and the constrained superfields formalism

TL;DR

This paper explores the relationship between the superconformal symmetry breaking superfield and the goldstino in microscopic models, analyzing the decoupling of scalar fields and the properties of the superfield in the infrared, with implications for coupling to realistic models.

Contribution

It provides a detailed analysis of the superfield X in models with arbitrary Kahler potential, showing it satisfies X^3=0 in the infrared, and compares this to the constrained superfield approach.

Findings

Superfield X satisfies X^3=0 after integrating out scalar fields.

In the infrared, X is characterized by specific algebraic constraints.

Results facilitate coupling goldstino fields to realistic models like the MSSM.

Abstract

We examine the exact relation between the superconformal symmetry breaking chiral superfield (X) and the goldstino superfield in microscopic models of an arbitrary Kahler potential (K) and in the presence of matter fields. We investigate the decoupling of the massive sgoldstino and scalar matter fields and the offshell/onshell-SUSY expressions of their superfields in terms of the fermions composites. For general K of two superfields, we study the properties of the superfield X after integrating out these scalar fields, to show that in the infrared it satisfies (offshell) the condition $X^3=0$ and $X^2\not=0$. We then compare our results to those of the well-known method of constrained superfields discussed in the literature, based on the conjecture $X^2=0$. Our results can be used in applications, to couple offshell the (s)goldstino fields to realistic models such as the MSSM.