Neutrino Masses within the Minimal Supersymmetric Standard Model

TL;DR

This paper explores how the minimal supersymmetric Standard Model can naturally incorporate neutrino masses consistent with solar neutrino observations, using a gravity-induced seesaw mechanism linked to string theory vacua.

Contribution

It proposes a novel gravity-induced seesaw mechanism within the MSSM that explains neutrino masses and unification scales, compatible with string theory models.

Findings

Neutrino masses proportional to quark masses squared over a high scale.

Compatibility with grand unification and string vacua.

Potential realization in large radius Calabi-Yau compactifications.

Abstract

We investigate the possibility of accommodating neutrino masses compatible with the MSW study of the Solar neutrino deficit within the minimal supersymmetric Standard Model. The ``gravity-induced'' seesaw mechanism based on an interplay of nonrenormalizable and renormalizable terms in the superpotential allows neutrino masses $m_\nu\propto m_u^2/M_I$, with $m_u$ the corresponding quark mass and $M_I\simeq 4\times10^{11}$ GeV, while at the same time ensuring the grand desert with the gauge coupling unification at $M_U\simeq 2\times10^{16}$ GeV. The proposed scenario may be realized in a class of string vacua, {\it i.e.,} large radius ($R^2/\alpha '={\cal O}(20)$) $(0,2)$ Calabi-Yau spaces. In this case $M_U^2=M_C^2/{\cal O} (2R^2/\alpha')$ and $M_I= {\cal O}(e^{-R^2/\alpha'})M_C$. Here $M_C=g\times 5.2\times 10^{17}$GeV is the scale of the tree level (genus zero) gauge coupling ($g$) unification.