Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Dr Dumitru Ghilencea, National Institute of Physics and Nuclear Engineering Bucharest
Andrei Constantin (andrei.constantin@physics.ox.ac.uk)
Abstract
Weyl conformal geometry can be regarded as a gauge theory of the Weyl group (of Poincare and dilatation symmetries) and is defined by equivalent classes of the metric and Weyl gauge boson of dilatations (ωμ), related by Weyl gauge transformations. The associated action with this gauge symmetry is the vector-tensor Weyl quadratic gravity. I will show the existence of a manifestly Weyl gauge-covariant formulation of this geometry, in which this geometry is actually metric, thus avoiding a century-old criticism of Einstein. Weyl gauge symmetry is broken à la Stueckelberg, ωμ becoming massive and decoupling, to recover Einstein gravity in the broken phase, corresponding to a transition from conformal geometry/connection to Riemannian geometry/connection. Weyl gauge symmetry is also free of the Weyl anomaly, recovered in the broken phase after the massive ωμ decouples. The action has a non-perturbative UV completion in a Weyl gauge invariant DBI-like action associated to conformal geometry. No scalar fields compensators or UV regulators are required. The Standard Model (SM) admits a natural embedding in conformal geometry, with no new degrees of freedom beyond SM and Weyl geometry. The implications of this embedding are briefly addressed.