Dark neutrinos and a three-portal connection to the standard model

Abstract

We introduce a dark neutrino sector which respects a hidden Uð1Þ 0 gauge symmetry, subsequently broken by the vacuum expectation value of a dark scalar. The model is a self-consistent realization of an extended hidden sector that communicates with the standard model only via the three renormalizable portals, namely, neutrino, vector and scalar mixing. The interplay between portal couplings leads to several novel signatures in heavy neutrino, dark photon, and dark scalar searches, typically characterized by multileptons plus missing energy and displaced vertices. A striking signature arises in kaon factories such as NA62, where K þ → l þ α νl þ β l − β decays could reveal a heavy neutrino and a light dark photon resonance above backgrounds. Given the open parameter space, we also comment on recent ideas to explain outstanding experimental anomalies, and how they would fit into our proposed model. A minimal extension of the model, possibly motivated by anomaly cancellation, can accommodate a dark matter candidate strongly connected to the neutrino sector.

Searching for eV-scale sterile neutrinos with eight years of atmospheric neutrinos at the IceCube Neutrino Telescope

“…It has motivated a worldwide program to search for new particle states with mass-squared differences between 0.1 and 10 eV 2 [6]. Notable other explanations include, for example, phenomenology that modifies the vacuum oscillation probability relevant to short-baseline neutrino experiments , modifications of neutrino propagation in matter [31][32][33][34][35], or production of new particles in the beam or in the detector and its surroundings [36][37][38][39][40][41][42][43][44][45][46][47][48][49].…”

“…The 3 þ 1 model is widely used as a benchmark for experimental datasets to examine whether they show evidence for a sterile neutrino. Extensions to this model have been proposed such as adding more neutrino mass states [53], allowing the heavier mass states to decay [27,48,49,54], or introducing secret neutrino interactions [32,[35][36][37]40,[44][45][46][47][55][56][57][58]; these more complex models are not considered further in this work.…”

Neutrino non-standard interactions: A status report

“…These explanations introduce simplified models that contain a dark neutrino, with a corresponding mass state m 4 , and a dark photon of mass m Z [200,226]. Interestingly, these models can be embedded into complete theories that would not only be an explanation of the MiniBooNE anomaly, but could also explain neutrino masses [199,227,228]. To explain the MiniBooNE anomaly they notice that MiniBooNE, a Cherenkov detector, cannot distinguish between photons and electrons.…”

“…Nevertheless, these signatures appear in a variety of new physics models where neutrino experiments provide very competitive bounds [199,349]. For instance, recent explanations of the excess of electron-like events at MiniBooNE have been put forward [200,226,228], where the excess is due to dielectron pairs which are spatially overlapping or highly asymmetric in energy. These models provide an interesting alternative to endow active neutrinos with new interactions and have strong connections to neutrino mass generation at low scales [199,227].…”

Explaining (g−2)μ,e , the KOTO anomaly, and the MiniBooNE excess in an extended Higgs model with sterile neutrinos

“…Recently, several attempts have been put forth to explain this anomaly within the context of dark neutrino mass models using heavy sterile neutrinos and dark gauge bosons [149][150][151][152][153][154] and dark sector models with dark scalars [142]. They all considered the scenario where the light neutrinos upscatter to a heavy neutrino after coherent scattering off the nucleus and subsequent decay of the heavy neutrino into a pair of electrons.…”