Neutrino Democracy And Other Phenomenology From 5D SO(10)

Abstract

We present a five dimensional supersymmetric SO(10) model compactified on an orbifold $S^{(1)}/Z_2\text{tm}{Z}_2^{\prime }$. The gauge symmetry $G_{422}\equiv SU(4{)}_c\text{tm}SU(2{)}_L\text{tm}SU(2{)}_R$, realized on one of the fixed points (branes), is spontaneously broken to the MSSM via the higgs mechanism. Employing a flavor $\mathcal{U}(1)$ symmetry and suitably extending the 'matter' sector enables us to understand large mixings in the neutrino sector via a democratic approach, versus the small CKM mixings. A residual $\mathcal{R}$-symmetry on $G_{422}$ brane helps eliminate the troublesome dimension five nucleon decay, while the $\mathcal{U}(1)$ symmetry plays an essential role in suppressing dimension six decay. For rare leptonic decays we expect $\mathrm{BR}(\mu \to e\text{ga})\sim \mathrm{BR}(\tau \to \mu \text{ga})\sim \mathrm{BR}(\tau \to e\text{ga})$.

Comments: Version to appear in Nucl. Phys. B