DS_5 vacua from matter-coupled 5D N=4 gauged supergravity

Abstract

We study dS_5 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 dS_5 as maximally symmetric background solutions. The results provide a new approach for finding dS_5 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)times G_{text {nc}} with G_{text {nc}} being a non-abelian non-compact group. In general, G_{text {nc}} can be a product of SO(1, 2) and a smaller non-compact group {G^{prime }}_{{text {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)sim USp(4) R-symmetry. The compact parts of SO(1, 2) and {G^{prime }}_{{text {nc}}} are gauged by vector fields from the gravity and vector multiplets, respectively. In addition, we explicitly study dS_5 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 dS_5 vacua identified here are unstable.