New physics from oscillations at the DUNE near detector, and the role of systematic uncertainties

Abstract

We study the capabilities of the DUNE near detector to probe deviations from unitarity of the leptonic mixing matrix, the 3+1 sterile formalism and Non-Standard Interactions affecting neutrino production and detection. We clarify the relation and possible mappings among the three formalisms at short-baseline experiments, and we add to current analyses in the literature the study of the νμ→ ντ appearance channel. We study in detail the impact of spectral uncertainties on the sensitivity to new physics using the DUNE near detector, which has been widely overlooked in the literature. Our analysis shows that this plays an important role on the results and, in particular, that it can lead to a strong reduction in the sensitivity to sterile neutrinos from νμ→ νe transitions, by more than two orders of magnitude. This stresses the importance of a joint experimental and theoretical effort to improve our understanding of neutrino nucleus cross sections, as well as hadron production uncertainties and beam focusing effects. Nevertheless, even with our conservative and more realistic implementation of systematic uncertainties, we find that an improvement over current bounds in the new physics frameworks considered is generally expected if spectral uncertainties are below the 5% level.

Model-independent constraints on non-unitary neutrino mixing from high-precision long-baseline experiments

“…In the literature, many theoretical/phenomenological studies have been performed to investigate the possible signatures of non-unitarity of the three-flavor neutrino mixing matrix in the context of neutrino oscillation experiments. Considerable efforts have been made to study the possible impact of NUNM on the measurement of leptonic CP phase δ CP , determination of the neutrino mass-hierarchy [43][44][45][46][47][48], and in estimating the performance of current and future long-baseline experiments to constrain the various NUNM parameters [37,39,[49][50][51][52][53][54][55][56][57][58].…”

Non-unitarity and sterile neutrinos at the DUNE near detector

“…In this section, we will present our main results of our paper, for the rest of the results including the sensitivity analysis for NSI in detection and production check [1].…”

“…In this section, we will briefly introduce the two theoretical scenarios that we will consider in our sensitivity analysis: non-unitarity and sterile neutrinos. For a more detailed discussion see [1].…”

“…Indeed, the bounds we show in Fig 1, which come from oscillation experiments are considerably weaker and apply to the average-out regime of the steriles. See [1] for details.…”

New oscillation and scattering constraints on the tau row matrix elements without assuming unitarity

“…In the (4,4) case these experiments provide a constraint on the second term in the oscillation probability which depends as Pµτ ∝ U µ4 U τ 4 (see also [85]). With a prior on U µ4 from the normalization of the muon row from [9] which is compatible with 0 at 1σ this also means that the oscillation probability P µτ is compatible with 0 at 1σ, hence we do not obtain a constraint on U τ 4 from NOMAD alone (equal arguments apply to P eτ ) in the (4,4) case.…”