\theta_13, Rare Processes and Proton Decay in Flipped SU(5)

Abstract

We consider an extended flipped SU(5) model, supplemented by a flavor $\mathcal{U}(1)$ symmetry, which yields bi-large neutrino mixings, charged fermion mass hierarchies and CKM mixings. The third leptonic mixing angle ${\text{te}}_{13}$ turns out to lie close to 0.07, and neutrino CP violation can be estimated from the observed baryon asymmetry. For lepton flavor violating processes we find the branching ratios, $\mathrm{BR}(\mu \to e\text{ga})\sim \mathrm{BR}(\tau \to e\text{ga})\sim 10^{-4}\cdot \mathrm{BR}(\tau \to \mu \text{ga})\stackrel{<}{{}_{\sim }}5\cdot 10^{-14}$. The proton lifetime ${\tau }_{p\to {\pi }^0{e}^{+}}\simeq 10^{34}-10^{36}$ yrs.

Comments: Discussion on leptogenesis and CP violation, and references added