Constraining the (Low-Energy) Type-I Seesaw

TL;DR

This paper discusses how upcoming short-baseline neutrino oscillation experiments could potentially confirm or exclude the low-energy Type-I seesaw model for neutrino masses, especially for right-handed neutrinos below 10 eV.

Contribution

It highlights the potential of future experiments to test the low-energy seesaw model by measuring specific neutrino oscillation channels and constraining the model's parameters.

Findings

Next-generation experiments can potentially rule out or confirm the low-energy seesaw.

Multiple oscillation channels are crucial for testing the model.

Light right-handed neutrinos (<10 eV) are accessible to experimental tests.

Abstract

The type-I seesaw Lagrangian yields a non-generic set of active-sterile oscillation parameters - the neutrino mass eigenvalues and the physical elements of the full mixing matrix are entwined. For this reason one is able to, in principle, test the model by performing enough measurements which are sensitive to neutrino masses and lepton mixing. We point out that for light enough right-handed neutrino masses - less than 10 eV - next-generation short-baseline neutrino oscillation experiments may be able to unambiguously rule out (or "rule in") the low energy seesaw as the Lagrangian that describes neutrino masses. These types of searches are already under consideration in order to address the many anomalies from accelerator neutrino experiments (LSND, MiniBooNe), reactor neutrino experiments (the "reactor anomaly") and others. In order to test the low-energy seesaw, it is crucial to explore different oscillation channels, including nu_e and nu_mu disappearance and nu_mu to nu_tau appearance.