Speaker
Description
The origin of neutrino masses suggests the existence of a sterile neutrino sector, which may be either too heavy or too weakly coupled to the Standard Model (SM) to be detected in the near future. The inverse seesaw mechanism provides a testable framework where the coupling between the sterile sector and the SM is large enough to allow direct experimental probes. In this context, it is crucial to explore whether the sterile sector is a weakly or strongly coupled theory and to identify methods to distinguish between these possibilities.
We propose a novel experimental probe for neutrino coupling with a strongly coupled sterile sector, based on the distinctive signature of neutrino disintegration into ``dark jets'' in high-energy neutrino scattering with electrons and nucleons. If the confinement scale of the sterile sector is below the center of mass energy of the collisions the neutrinos disintegrate into dark-sector jets. As the dark shower evolves, dark bound states form and eventually decay into Standard Model particles with finite lifetimes. If these decays occur outside the detector, the resulting invisible jet manifests as missing energy. Alternatively, if decays happen at macroscopic distances from the interaction point, they generate a distinctive signature known as an emerging jet. These jets are semi-visible, containing missing energy from Standard Model neutrinos, and their detailed structure is determined by the nature of the portal connecting the visible and dark sectors. We compute the expected signal rates for such events at various upcoming neutrino beamline experiments, as well as at charged lepton beams highlighting their sensitivity to the compositeness of the neutrino sector.
The unique signals discussed here offer a new experimental signature for future neutrino experiments, presenting both challenges in optimizing signal-to-background discrimination and a promising avenue for identifying composite neutrino interactions.