dS5 vacua from matter-coupled 5D N= 4 gauged supergravity

Abstract

We study dS5 vacua within matter-coupled N= 4 gauged supergravity in five dimensions using the embedding tensor formalism. With a simple ansatz for solving the extremization and positivity of the scalar potential, we derive a set of conditions for the gauged supergravity to admit dS5 as maximally symmetric background solutions. The results provide a new approach for finding dS5 vacua in five-dimensional N= 4 gauged supergravity and explain a number of notable features pointed out in previous works. These conditions also determine the form of the gauge groups to be SO(1 , 1) × Gnc with Gnc being a non-abelian non-compact group. In general, Gnc can be a product of SO(1, 2) and a smaller non-compact group G?nc together with (possibly) a compact group. The SO(1, 1) factor is gauged by one of the six graviphotons, that is singlet under SO(5) ? USp(4) R-symmetry. The compact parts of SO(1, 2) and G?nc are gauged by vector fields from the gravity and vector multiplets, respectively. In addition, we explicitly study dS5 vacua for a number of gauge groups and compute scalar masses at the vacua. As in the four-dimensional N= 4 gauged supergravity, all the dS5 vacua identified here are unstable. © 2019, The Author(s).