BSM and SM signals and backgrounds in Far-Forward Experiments at the LHC

TL;DR

This paper discusses the current and future potential of far-forward experiments at the LHC, focusing on signals and backgrounds for BSM and SM particles, especially in the context of QCD-related phenomena.

Contribution

It provides an analysis of BSM and SM signals and backgrounds in far-forward experiments at the LHC, highlighting prospects for the upcoming HL-LHC phase and the proposed Forward Physics Facility.

Findings

Current experiments FASER and FASERν detect BSM particles, muons, and neutrinos.

Backgrounds and signals at the FPF are analyzed, emphasizing QCD-related aspects.

Extensions to larger experiments during HL-LHC are discussed.

Abstract

Two far-forward experimental systems are currently taking data during Run 3 at the Large Hadron Collider (LHC): FASER + FASER$\nu$ and SND@LHC. They are sensitive to some classes of beyond-the-Standard Model (BSM) particles, muons and neutrinos produced in the ATLAS interaction point (IP) and propagating for several hundred meters along the tangent to the accelerator beamline, up to the caverns where they are respectively located, in opposite directions with respect to the IP. Proposals are being prepared to extend these experiments to bigger ones during the HL-LHC phase. Building a Forward Physics Facility (FPF) capable of hosting a number of far-forward experiments characterized by different detection techniques, kinematical acceptance and purpose, is a possibility also under discussion. In this contribution I discuss some of the BSM and SM signals and backgrounds at the FPF, mainly focusing on QCD-related aspects.