SND@LHC

SND@LHC is a recently approved, compact and stand-alone experiment to perform measurements with neutrinos produced at the LHC in a hitherto unexplored pseudo-rapidity range of 7.2 < 𝜂 < 8.6, complementary to all the other experiments at the LHC, including FASER.
Two effects make it possible and particularly interesting to construct and operate a compact neutrino detector at the LHC. The high luminosity of proton-proton collisions achieved by the machine lead to a large neutrino flux in the forward direction, and the high neutrino energies imply relatively large neutrino cross-sections. As a result, even a detector with a relatively modest size to fit into one of the existing underground areas has a significant physics potential. Machine-induced backgrounds decrease rapidly with increasing distance from the interaction point and away from the beam line.

Proposed implementation of the detector close to the ATLAS experiment.

In the pseudo-rapdity range explored by the experiment, electron neutrinos and anti-neutrinos are predominantly produced by charmed-hadron decays. As a result, SND@LHC is capable of measuring charmed-hadron production indirectly through the observation of electron neutrinos and anti-neutrinos. Performance studies show that the charmed-hadron production in the SND@LHC pseudo-rapidity range can be determined with an accuracy of 35%. This result will be used to constrain the gluon parton density function in an unexplored region of very-small x. This is of particular interest also for experiments operating at future larger accelerators where this regime is relevant.

Outline of the target, the calorimeter and muon system