Motivated by principles from the Swampland program, which characterize requirements for a consistent UV completion of quantum gravity, combined with observational data, we are led to a unique corner of the quantum gravity landscape. In particular, using the Distance/Duality conjecture and the smallness of dark energy, we predict the existence of a light tower of states and a unique extra mesoscopic dimension of length $l\sim \Lambda^{ -\frac{ 1}{ 4}}\sim 10^{ -6}\, m$, with extra massless fermions propagating on it. This automatically leads to a candidate for a tower of sterile neutrinos, and an associated active neutrino mass scale $m_{ \nu}\sim \langle H\rangle^2\, \Lambda^{ -\frac{ 1}{ 12}}M_{ pl}^{ -\frac{ 2}{ 3}}$. Moreover, assuming the mechanism for stabilization of this dark dimension leads to similar masses for active and sterile neutrinos we are led to the prediction of a Higgs vev $\langle H\rangle \sim \Lambda^{ \frac{ 1}{ 6}}M_{ pl}^{ \frac{ 1}{ 3}}$. Another prediction of the scenario is a species scale ${ \hat M} \sim \Lambda^ { \frac{ 1}{ 12}}M_{ pl}^{ \frac{ 2}{ 3}}\sim 10^{ 9}-10^{ 10} GeV$, corresponding to the higher-dimensional Planck scale. This energy scale may be related to the resolution of the instability of the Higgs effective potential present at a scale of $\sim 10^{ 11}\, GeV$. We also speculate about the interplay between this energy scale and the GZK limit on ultra-high energy cosmic rays.
Categories: hep-th hep-ph