Scalar-Tensor multiplet in four dimensional N=2 conformal supergravity

TL;DR

This paper explores the structure of N=2 multiplets in four-dimensional supergravity by truncating N=3 multiplets, leading to a new off-shell scalar-tensor multiplet with specific field content.

Contribution

It introduces a novel off-shell scalar-tensor multiplet derived from supersymmetric truncation of N=3 multiplets, expanding the understanding of matter multiplets in supergravity.

Findings

Reduction of N=3 Weyl multiplet to N=2 Weyl and vector multiplets.

Derivation of a new off-shell scalar-tensor multiplet with 8+8 degrees of freedom.

Use of hypermultiplet field equations to eliminate fields and construct the multiplet.

Abstract

We study various N=2 multiplets in four dimensions by looking at the supersymmetric truncation of four dimensional N=3 multiplets. Under supersymmetric truncation, the off-shell N=3 Weyl multiplet reduces to the off-shell N=2 Weyl multiplet and the off-shell N=2 vector multiplet (which we will refer to as the central charge multiplet). Under the same truncation, the on-shell N=3 vector multiplet reduces to the on-shell N=2 vector multiplet and an on-shell massive hypermultiplet with a broken rigid SU(2) and a non-trivial central charge transformation. We use the field equations of this hypermultiplet to eliminate some of the fields of the central charge multiplet in terms of the fields of the hypermultiplet and a dual tensor gauge field (similar in spirit to how a dilaton Weyl multiplet is constructed). This results in a new off-shell matter multiplet, with 8+8 degrees of freedom, containing scalar fields and a tensor gauge field, which we refer to as the scalar-tensor multiplet.