Observation of collider muon neutrinos with the SND@LHC experiment

We report the direct observation of muon neutrino interactions with the SND@LHC detector at the Large Hadron Collider. A data set of proton-proton collisions at $\sqrt{s}=13.6$TeV collected by SND@LHC in 2022 is used, corresponding to an integrated luminosity of 36.8${\mathrm{f}\mathrm{b}}^{-1}$. The search is based on information from the active electronic components of the SND@LHC detector, which covers the pseudo-rapidity region of $7.2<\eta <8.4$, inaccessible to the other experiments at the collider. Muon neutrino candidates are identified through their charged-current interaction topology, with a track propagating through the entire length of the muon detector. After selection cuts, 8 ${\nu }_{\mu }$ interaction candidate events remain with an estimated background of 0.076 events, yielding a significance of seven standard deviations for the observed ${\nu }_{\mu }$ signal.