Technical Proposal for FASER: ForwArd Search ExpeRiment at the LHC

TL;DR

FASER is a cost-effective experiment proposed to detect light, weakly-interacting particles produced at the LHC, aiming to extend discovery potential during Run 3 by capturing particles decaying hundreds of meters from the collision point.

Contribution

This paper presents the technical design, components, and installation plan for the FASER detector, a novel experiment to search for new light particles at the LHC.

Findings

Design of FASER detector components detailed

Preliminary cost estimates provided

Installation timeline outlined

Abstract

FASER is a proposed small and inexpensive experiment designed to search for light, weakly-interacting particles during Run 3 of the LHC from 2021-23. Such particles may be produced in large numbers along the beam collision axis, travel for hundreds of meters without interacting, and then decay to standard model particles. To search for such events, FASER will be located 480 m downstream of the ATLAS IP in the unused service tunnel TI12 and be sensitive to particles that decay in a cylindrical volume with radius R=10 cm and length L=1.5 m. FASER will complement the LHC's existing physics program, extending its discovery potential to a host of new, light particles, with potentially far-reaching implications for particle physics and cosmology. This document describes the technical details of the FASER detector components: the magnets, the tracker, the scintillator system, and the calorimeter, as well as the trigger and readout system. The preparatory work that is needed to install and operate the detector, including civil engineering, transport, and integration with various services is also presented. The information presented includes preliminary cost estimates for the detector components and the infrastructure work, as well as a timeline for the design, construction, and installation of the experiment.