Flat deformations of type IIB S-folds

Abstract

Abstract Type IIB S-folds of the form AdS4× S1× S5 have been shown to contain axion-like deformations parameterising flat directions in the 4D scalar potential and corresponding to marginal deformations of the dual S-fold CFT’s. In this note we present a group-theoretical characterisation of such flat deformations and provide a 5D interpretation thereof in terms of $$ \mathfrak{s}(6) $$ s 6 -valued duality twists inducing a class of Cremmer-Scherk-Schwarz flat gaugings in a reduction from 5D to 4D. In this manner we establish the existence of two flat deformations for the $$ \mathcal{N} $$ N = 4 and SO(4) symmetric S-fold causing a symmetry breaking down to its U(1)2 Cartan subgroup. The result is a new two-parameter family of non-supersymmetric S-folds which are perturbatively stable at the lower-dimensional supergravity level, thus providing the first examples of such type IIB backgrounds.