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 <math display="inline"><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math> collider neutrinos using its emulsion-based neutrino detector <math display="inline"><mi>FASER</mi><mi>ν</mi></math>. In this study, we show that, even without processing the emulsion data, low-level input provided by the electronic detector components of FASER and <math display="inline"><mi>FASER</mi><mi>ν</mi></math> will be able to establish a <math display="inline"><mn>5</mn><mi>σ</mi></math> discovery of collider neutrinos with as little as <math display="inline"><mn>5</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>-</mo><mn>1</mn></mrow></msup></math> of integrated luminosity. These results foreshadow the possible early discovery of collider neutrinos in LHC run 3.