Early performance of the tracking detector for the FASER experiment

FASER is a new experiment aimed at searching for new light weakly-interacting long-lived particles and studying high-energy neutrino interactions in the very forward region of LHC collisions at CERN. The experimental setup is located 480 meters downstream from the ATLAS interaction point, aligned with the beam collision axis. The FASER detector comprises four identical tracker stations made from silicon microstrip detectors. All tracker stations were installed in the LHC complex in 2021. After the commissioning, FASER has been taking physics data since the start of LHC Run 3 in July 2022. In 2022 and 2023, we have successfully collected data from 68 fb−1 (inverse femtobarns) of proton–proton collisions at a center-of-mass energy of 13.6 TeV. This paper describes the design, construction and performance with early data of the silicon tracker stations.