Phenomenological Issues in TeV scale Gravity with Light Neutrino Masses

TL;DR

This paper explores how large extra dimensions with light neutrinos can cause observable violations of lepton universality and flavor changing processes, constraining the string scale to around 10 TeV.

Contribution

It analyzes the phenomenological implications of bulk singlet neutrinos in large extra dimensions, highlighting their effects on low-energy lepton observables and setting bounds on the string scale.

Findings

Lepton universality violation is induced by neutrino mixing.

Flavor changing processes are enhanced in this scenario.

Experimental data constrains the string scale to about 10 TeV.

Abstract

The possible existence of bulk singlet neutrinos in the scenario with large compactified dimensions and low string scale $M_*$ has important consequences for low-energy observables. We demonstrate that intergenerational mass splitting and mixing lead to the effective violation of the lepton universality and flavor changing processes in charged lepton sector. Current experimental constraints push $M_*$ to the scale of 10 TeV over most of the interesting range for neutrino mass splitting.