Probing Large Extra Dimensions with Neutrinos

TL;DR

This paper explores how theories with large extra dimensions at TeV scales affect neutrino physics, proposing that neutrino oscillations and resonance conversions could explain solar neutrino observations and link to gravity experiments.

Contribution

It introduces a model where neutrino oscillations involve bulk fermions in large extra dimensions, providing a novel solution to the solar neutrino problem and connecting neutrino physics with gravity tests.

Findings

Resonance conversion of electron neutrinos to bulk fermions can solve the solar neutrino problem.

The size of at least one extra dimension is constrained to 0.06-0.1 mm by neutrino data.

Predicted modifications to Newtonian gravity are within experimental detection range.

Abstract

We study implications of theories with sub-millimeter extra dimensions and $M_f \sim (1 - 10) $ TeV scale quantum gravity for neutrino physics. In these theories, the left-handed neutrinos as well as other standard model (SM) particles, are localized on a brane embedded in the bulk of large extra space. Mixing of neutrinos with (SM) singlet fermions propagating in the bulk is naturally suppressed by the volume factor $M_f/M_P \sim 3\cdot 10^{-16} - 3\cdot 10^{-15}$, where $M_P$ is the Planck mass. Properties of the neutrino oscillations and the resonance conversion to the bulk fermions are considered. We show that the resonance conversion of the electron neutrinos to the light bulk fermions can solve the solar neutrino problem. The signature of the solution is the peculiar distortion of the solar neutrino spectrum. The solution implies that the radius of at least one extra dimension should be in the range 0.06 - 0.1 mm {\it irrespective} of total number of extra dimensions. The corresponding modification of the Newtonian law is within the range of sensitivity of proposed sub-millimeter experiments, thus providing a verifiable link between neutrino physics and the gravity measurements.