Neutrino discovery limit of Dark Matter direct detection experiments in the presence of non-standard interactions

M. C. Gonzalez-Garcia,Yuber F. Perez-Gonzalez,Michele Maltoni,Renata Zukanovich Funchal

doi:10.1007/jhep07(2018)019

Abstract

The detection of coherent neutrino-nucleus scattering by the COHERENT collaboration has set on quantitative grounds the existence of an irreducible neutrino background in direct detection searches of Weakly Interacting Massive Dark Matter candidates. This background leads to an ultimate discovery limit for these experiments: a minimum Dark Matter interaction cross section below which events produced by the coherent neutrino scattering will mimic the Dark Matter signal, the so-called neutrino floor. In this work we study the modification of such neutrino floor induced by non-standard neutrino interactions within their presently allowed values by the global analysis of oscillation and COHERENT data. By using the full likelihood information of such global analysis we consistently account for the correlated effects of non-standard neutrino interactions both in the neutrino propagation in matter and in its interaction in the detector. We quantify their impact on the neutrino floor for five future experiments: DARWIN (Xe), ARGO (Ar), Super-CDMS HV (Ge and Si) and CRESST phase III (CaWO4). Quantitatively, we find that non-standard neutrino interactions allowed at the 3σ level can result in an increase of the neutrino floor of up to a factor ∼ 5 with respect to the Standard Model expectations and impact the expected sensitivities of the ARGO, CRESST phase III and DARWIN experiments.

Highlights

The detection of coherent neutrino-nucleus scattering by the COHERENT collaboration has set on quantitative grounds the existence of an irreducible neutrino background in direct detection searches of Weakly Interacting Massive Dark Matter candidates
This background leads to an ultimate discovery limit for these experiments: a minimum Dark Matter interaction cross section below which events produced by the coherent neutrino scattering will mimic the Dark Matter signal, the so-called neutrino floor
A WIMP direct detection experiment is based on a simple principle: if a WIMP interacts with the quarks of a nucleus, it should be possible to detect such interaction by measuring the nuclear recoil produced on a target material

Summary

NC-NSI Lagrangian and constraints

In this work we consider NC-NSI affecting neutral-current processes relevant to neutrino coherent scattering in DM experiments. For what concerns bounds from non-oscillation experiments, generically NC-NSI parameters in gauge invariant models of new physics at high energies are expected to be subject to tight constraints from charged lepton observables [59, 60] and directly from collider data (see for example [61]) For those constructions the bounds on the NC-NSI of neutrinos are too strong to lead to any observable effect in direct dark matter detection experiments. As seen in the figure the combination of oscillation and COHERENT results is able to impose constraints on all the relevant vector-like NC-NSI coefficients even when they are varied simultaneously in the analysis In this respect, it is important to notice that, in order to consistently obtain the allowed effects on the neutrino floor at a given CL as presented, we use the full multidimensional ∆χ2 dependence on the NC-NSI and oscillation parameters so to correctly account for the correlations among their allowed ranges It is important to notice that, in order to consistently obtain the allowed effects on the neutrino floor at a given CL as presented we use the full multidimensional ∆χ2 dependence on the NC-NSI and oscillation parameters so to correctly account for the correlations among their allowed ranges

Neutrino rate at direct detection experiments

Results

Conclusions