Dilatations Revisited

Abstract

Dilatation, i.e. scale, symmetry in the presence of the dilaton in Minkowski space is derived from diffeomorphism symmetry in curved spacetime, incorporating the volume-preserving diffeomorphisms. The conditions for scale invariance are derived and their relation to conformal invariance is examined. In the presence of the dilaton scale invariance automatically guarantees conformal invariance due to diffeomorphism symmetry. Low energy scale-invariant phenomenological Lagrangians are derived in terms of dilaton-dressed fields, which are identified as the fields satisfying the usual scaling properties. The notion of spontaneous scale symmetry breaking is defined in the presence of the dilaton. In this context, possible phenomenological implications are advocated and by computing the dilaton mass the idea of PCDC (partially conserved dilatation current) is further explored.