A small weak scale from a small cosmological constant

Understand

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.