Power law enhancement of neutrino mixing angles in extra dimensions
  We study the renormalization of the $llHH$-type Majorana neutrino mass operator in a scenario where there is a compactified extra dimension and the fields involved correspond to only the standard model particles and their Kaluza-Klein excitations. We observe that in a two flavour scenario, where one of the neutrinos is necessarily $\nu_\tau$, it is indeed possible to generate a large mixing at $\sim$ 100 GeV starting from a very small mixing near the ultra-violet cutoff $\sim$ 30 TeV. {\em En passant}, we also derive the Higgs mass upper and lower limits from perturbative unitarity and stability of the potential, respectively. 
Gautam Bhattacharyya, Srubabati Goswami, Amitava Raychaudhuri