Neutrino detection without neutrino detectors: Discovering collider neutrinos at FASER with electronic signals only

The detection of collider neutrinos will provide new insights about neutrino production, propagation, and interactions at TeV energies, the highest human-made energies ever observed. During Run 3 of the LHC, the FASER experiment is expected to detect roughly 10 4 collider neutrinos using its emulsion-based neutrino detector FASER ν . In this study, we show that, even without processing the emulsion data, low-level input provided by the electronic detector components of FASER and FASER ν will be able to establish a 5 σ discovery of collider neutrinos with as little as 5 fb − 1 of integrated luminosity. These results foreshadow the possible early discovery of collider neutrinos in LHC Run 3.