Consistent S2 Pauli reduction of six-dimensional chiral gauged Einstein-Maxwell supergravity

Six-dimensional N=(1,0) Einstein-Maxwell gauged supergravity is known to admit a (Minkowski)4xS2 vacuum solution with four-dimensional N=1 chiral supersymmetry. The massless sector comprises a supergravity multiplet, an SU(2) Yang-Mills vector multiplet, and a scalar multiplet. In this paper it is shown that, remarkably, the six-dimensional theory admits a fully consistent dimensional reduction on the 2-sphere, implying that all solutions of the four-dimensional N=1 supergravity can be lifted back to solutions in six dimensions. This provides a striking realisation of the idea, first proposed by Pauli, of obtaining a theory that includes Yang-Mills fields by dimensional reduction on a coset space. We address the cosmological constant problem within this model, and argue that, contrary to recent suggestions, fine-tuning is still required. We also suggest a link between a modification of the model with 3-branes, and a five-dimensional model based on an S1/Z2 orbifold