Large, Extra Dimensions at the Deep Underground Neutrino Experiment

TL;DR

This paper explores how the Deep Underground Neutrino Experiment (DUNE) can test large-extra-dimension models that explain neutrino masses, showing that DUNE can effectively distinguish these models from standard and other neutrino frameworks.

Contribution

It demonstrates DUNE's potential to probe large-extra-dimension models and clarifies their observable effects on neutrino oscillations, including their similarity to multi-neutrino scenarios.

Findings

DUNE can effectively test LED models through neutrino oscillation measurements.

LED models are nearly indistinguishable from a (3+3N) neutrino framework for small N.

No additional CP-violation sources are introduced by LED models beyond the standard phase.

Abstract

We investigate the potential of the long-baseline Deep Underground Neutrino Experiment (DUNE) to study large-extra-dimension (LED) models originally proposed to explain the smallness of neutrino masses by postulating that right-handed neutrinos, unlike all standard model fermion fields, can propagate in the bulk. The massive Kaluza-Klein (KK) modes of the right-handed neutrino fields modify the neutrino oscillation probabilities and can hence affect their propagation. We show that, as far as DUNE is concerned, the LED model is indistinguishable from a $(3 + 3N)$-neutrino framework for modest values of $N$; $N$ = 1 is usually a very good approximation. Nonetheless, there are no new sources of $CP$-invariance violation other than one $CP$-odd phase that can be easily mapped onto the $CP$-odd phase in the standard three-neutrino paradigm. We analyze the sensitivity of DUNE to the LED framework, and explore the capability of DUNE to differentiate the LED model from the three-neutrino scenario and from a generic $(3 + 1)$-neutrino model.