Decoupling Limits of sGoldstino Modes in Global and Local Supersymmetry

TL;DR

This paper investigates the decoupling of a superheavy sgoldstino in N=1 supergravity using Kähler superspace, revealing conditions for non-linear supersymmetry and identifying key superfields in the decoupling limit.

Contribution

It provides a detailed analysis of the decoupling limit of sgoldstino fields in supergravity, employing Kähler superspace to clarify the role of Kähler curvature and supersymmetry constraints.

Findings

Decoupling corresponds to infinite negative Kähler curvature.

Constraints lead to non-linear supersymmetry realizations.

Identification of the superconformal symmetry breaking superfield.

Abstract

We study the decoupling limit of a superheavy sgoldstino field in spontaneously broken N=1 supergravity. Our approach is based on K\"ahler superspace, which, among others, allows direct formulation of N=1 supergravity in the Einstein frame and correct identifications of mass parameters. Allowing for a non-renormalizable K\"ahler potential in the hidden sector, the decoupling limit of a superheavy sgoldstino is identified with an infinite negative K\"ahler curvature. Constraints that lead to non-linear realizations of supersymmetry emerge as consequence of the equations of motion of the goldstino superfield when considering the decoupling limit. Finally, by employing superspace Bianchi identities, we identify the real chiral superfield, which will be the superconformal symmetry breaking chiral superfield that enters the conservation of the Ferrra-Zumino multiplet in the field theory limit of N=1 supergravity.