A small weak scale from a small cosmological constant

TL;DR

This paper presents a novel framework where the smallness of the weak scale and the cosmological constant are interconnected, involving extra dimensions, chiral dynamics, and observable light scalars, offering testable predictions.

Contribution

It introduces a model linking the hierarchy problem to the cosmological constant problem through extra-dimensional stabilization mechanisms and predicts detectable light scalars.

Findings

The radion appears as a light scalar within reach of current experiments.

The fermion sector predicts mass relations related to the weak scale.

The model provides a natural explanation for the small weak scale and cosmological constant.

Abstract

We propose a framework in which Weinberg's anthropic explanation of the cosmological constant problem also solves the hierarchy problem. The weak scale is selected by chiral dynamics that controls the stabilization of an extra dimension. When the Higgs vacuum expectation value is close to a fermion mass scale, the radius of an extra dimension becomes large, and develops an enhanced number of vacua available to scan the cosmological constant down to its observed value. At low energies, the radion necessarily appears as an unnaturally light scalar, in a range of masses and couplings accessible to fifth-force searches as well as scalar dark matter searches with atomic clocks and gravitational-wave detectors. The fermion sector that controls the size of the extra dimension consists of a pair of electroweak doublets and several singlets. These leptons satisfy approximate mass relations related to the weak scale and are accessible to the LHC and future colliders.