SEZIONE DI MILANO
I present a (non-supersymmetric) theory with a naturally light dilaton. It is realized as a 5D holographic description of a conformal theory perturbed by a close-to-marginal operator which develops a condensate. As long as the dimension of the perturbing operator remains very close to marginal (even for large couplings) a stable minimum at hierarchically small scales is achieved, where the dilaton mass squared is suppressed by the small deviation from exact marginality. At the same time the cosmological constant in this sector is also suppressed by the same factor, and thus parametrically smaller than the condensate scale. As a byproduct I also present an exact solution to the scalar-gravity system that can be interpreted as a new holographic realization of spontaneously broken conformal symmetry. Even though this metric deviates substantially from AdS space in the deep IR it still describes a non-linearly realized exactly conformal theory. Brando Bellazzini IPhT - CEA/Saclay

DATA: 06-03-2014