Scalar Potential and Dyonic Strings in 6D Gauged Supergravity

In this paper we first give a simple parametrization of the scalar coset manifold of the only known anomaly free chiral gauged supergravity in six dimensions in the absence of linear multiplets, namely gauged minimal supergravity coupled to a tensor multiplet, E_6 x E_7 x U(1)_R Yang-Mills multiplets and suitable number of hypermultiplets. We then construct the potential for the scalars and show that it has a unique minimum at the origin. We also construct a new BPS dyonic string solution in which U(1)_R x U(1) gauge fields, in addition to the metric, dilaton and the 2-form potential, assume nontrivial configurations in any U(1)_R gauged 6D minimal supergravity coupled to a tensor multiplet with gauge symmetry G\supseteq U(1). The solution preserves 1/4 of the 6D supersymmetries and can be trivially embedded in the anomaly free model, in which case the U(1) activated in our solution resides in E_7.