Non-unitarity and sterile neutrinos at the DUNE near detector

TL;DR

This paper evaluates the DUNE near detector's ability to detect sterile neutrinos and non-unitarity in the leptonic sector, emphasizing the importance of spectral uncertainties and tau appearance channels.

Contribution

It introduces the use of charged current tau appearance and spectral shape uncertainties into the analysis, enhancing sensitivity over previous studies.

Findings

Improved sensitivity to sterile neutrinos and non-unitarity.

Spectral uncertainties significantly impact detection capabilities.

Charged current tau appearance channel adds valuable information.

Abstract

We study the capabilities of the DUNE near detector to probe the 3+1 sterile formalism and the non-unitarity of the leptonic sector. We add to the current analyses in the literature, the use of the charged current events for the $\nu_{\tau}$ appearance channel and the consideration of the energy spectral uncertainty (shape uncertainty) for the different channels which plays an important role, especially at the near detector, and has been usually overlooked in the literature. We find that even with this more conservative and realistic approach, we still obtain an improvement in the sensitivity with respect to the current bounds.