The Neutrino Suppression Scale from Large Volumes

TL;DR

The paper argues that the observed scale of Majorana neutrino masses can naturally arise from the geometry of large-volume Type IIB flux compactifications. By placing the Standard Model on a small cycle within a very large compactification (𝒱 ∼ 10^{15}) and requiring TeV-scale supersymmetry, the dimension-five operator responsible for neutrino masses acquires a suppression Λ of order 10^{14} GeV, independent of the masses of heavy states integrated out. The result relies on nonperturbative aspects of the Kähler potential and matter metrics, and remains robust across string-theoretic realizations as long as lepton-number violation is allowed and the operator is present with order-one coefficients. This establishes a geometric link between the SUSY-breaking scale and neutrino masses, with implications for string phenomenology and model-building.

Abstract

We present an argument in which the scale ~ 0.1 eV associated with neutrino masses naturally appears in a a class of (very) large volume compactifications, being tied to a supersymmetry scale of 10^3 GeV and a string scale of 10^11 GeV. The masses are of Majorana type and there is no right-handed neutrino within the low-energy field theory. The suppression scale 10^14 GeV is independent of the masses of the heavy states that are integrated out. These kind of constructions appear naturally in Type IIB flux compactifications. However, the arguments that lead to this result rely only on a few geometrical features of the compactification manifold, and hence can be used independently of string theory.