Neutrino anomalies and large extra dimensions

Abstract

Theories with large extra dimensions can generate small neutrino masses when the standard model neutrinos are coupled to singlet fermions propagating in higher dimensions. The couplings can also generate mass splittings and mixings among the flavor neutrinos in the brane. We systematically study a minimal scenario involving only one singlet bulk fermion coupling weakly to the flavor neutrinos. We explore the neutrino mass structures in the brane that can potentially account for the atmospheric, solar and Liquid Scintillation Neutrino Detector anomalies simultaneously in a natural way. We demonstrate that in the absence of a priori mixings among the standard model (SM) neutrinos, it is not possible to reconcile all these anomalies. The presence of some structure in the mass matrix of the SM neutrinos can solve this problem. This is exemplified by the Zee model, which when embedded in extra dimensions in a minimal way can account for all the neutrino anomalies.