On Relations Between Electroweak Hierarchy Problem, Fluctuating Three Branes And General Covariance

Abstract

We inquire whether a resolution to the electroweak hierarchy problem could reside in symmetries that relate the bosonic Weinberg-Salam Lagrangian with a higher dimensional generally covariant theory. For this we consider a three-brane that moves under the influence of a seven dimensional pure Hilbert Einstein-like generally covariant theory. We introduce a change of variables that combines the conformal scale of the metric tensor with the brane fluctuations, so that the conformal scale becomes the modulus and the fluctuations become the angular field degrees of freedom of a polarly decomposed Higgs. When we assume that the four dimensional space-time background of the generally covariant theory is locally conformally flat and that the internal space is a squashed three-sphere, we arrive at one massless and three massive vector fields akin those in the Weinberg-Salam model and recover all the familiar ingredients of the symmetry broken bosonic Weinberg-Salam model, except that there is no bare Higgs mass. The Higgs mass is subject to dimensional censorship, its presence is forbidden by general covariance. This proposes that a resolution to the electroweak hierarchy problem might well reside in higher dimensions, in a Ward-Takahashi like identities for general covariance that relate a non-vanishing Higgs mass to dynamical breaking of general covariance. Moreover, the two electroweak gauge couplings are both determined by the squashing parameter of the internal three sphere and when we impose the condition that the vector boson masses must be in line with custodial symmetry we arrive at the classical level to the Weinberg angle sin^2 \theta_W = 0.296.