Small Numbers from Tunneling Between Brane Throats

TL;DR

The paper explores how tunneling between brane throats in string compactifications can generate small physical parameters, offering new insights into the hierarchy problem and dark matter properties.

Contribution

It introduces a novel mechanism using brane throat tunneling to explain small numbers in physics, with applications to hierarchy and dark matter.

Findings

Tunneling provides a natural small number generation mechanism.

Long-lived conformal dark matter can decay within a Hubble time.

Couplings between throats are stronger than holographic estimates.

Abstract

Generic classes of string compactifications include ``brane throats'' emanating from the compact dimensions and separated by effective potential barriers raised by the background gravitational fields. The interaction of observers inside different throats occurs via tunnelling and is consequently weak. This provides a new mechanism for generating small numbers in Nature. We apply it to the hierarchy problem, where supersymmetry breaking near the unification scale causes TeV sparticle masses inside the standard model throat. We also design naturally long-lived cold dark matter which decays within a Hubble time to the approximate conformal matter of a long throat. This may soften structure formation at galactic scales and raises the possibility that much of the dark matter of the universe is conformal matter. Finally, the tunnelling rate shows that the coupling between throats, mediated by bulk modes, is stronger than a naive application of holography suggests.