New territory Two candidate collider-neutrino events from the FASERν pilot detector in the plane longitudinal to (top) and transverse to (bottom) the beam direction. The different lines in each event show charged-particle tracks originating from the neutrino interaction point. Credit: FASER Collaboration.
Topics: CERN, High Energy Physics, Particle Physics, Research
Think “neutrino detector” and images of giant installations come to mind, necessary to compensate for the vanishingly small interaction probability of neutrinos with matter. The extreme luminosity of proton-proton collisions at the LHC, however, produces a large neutrino flux in the forward direction, with energies leading to cross-sections high enough for neutrinos to be detected using a much more compact apparatus.
In March, the CERN research board approved the Scattering and Neutrino Detector (SND@LHC) for installation in an unused tunnel that links the LHC to the SPS, 480 m downstream from the ATLAS experiment. Designed to detect neutrinos produced in a hitherto unexplored pseudo-rapidity range (7.2 < 𝜂 < 8.6), the experiment will complement and extend the physics reach of the other LHC experiments — in particular FASERν, which was approved last year. Construction of FASERν, which is located in an unused service tunnel on the opposite side of ATLAS along the LHC beamline (covering |𝜂|>9.1), was completed in March, while installation of SND@LHC is about to begin.
Both experiments will be able to detect neutrinos of all types, with SND@LHC positioned off the beamline to detect neutrinos produced at slightly larger angles. Expected to commence data-taking during LHC Run 3 in spring 2022, these latest additions to the LHC experiment family are poised to make the first observations of collider neutrinos while opening new searches for feebly interacting particles and other new physics.
Collider neutrinos on the horizon, Matthew Chalmers, CERN Courier