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 10⁴ collider neutrinos using its emulsion-based neutrino detector FASERν. In this study, we show that, even without processing the emulsion data, low-level input provided by the electronic detector components of FASER and FASERν will be able to establish a 5σ 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.