Highlight: Forward Physics (LHCf + FASER)

TL;DR

The paper discusses the upcoming Run III of the LHC, highlighting the unique contributions of the LHCf and FASER experiments in forward physics, cosmic-ray modeling, and new particle searches, with expected significant advancements in each area.

Contribution

It presents the planned measurements and searches of LHCf and FASER during Run III, emphasizing their novel roles in cosmic-ray physics, new particle discovery, and neutrino production at colliders.

Findings

Enhanced measurements of forward particle production at 14 TeV

First collider measurement of neutrino production with FASER Potential discovery of new weakly-interacting particles

Improved constraints on hadronic interaction models

Abstract

The LHC Run III will be a crucial run for the two LHC forward experiments: LHCf and FASER. In particular, Run III will be the last run where the LHCf detector can operate and, at the same time, the first run of the new FASER project. The LHCf experiment is dedicated to precise measurements of forward production, necessary to tune hadronic interaction models employed in cosmic-ray physics. In Run III, the experiment will accomplish two fundamental goals: operating in p-p collisions at $\sqrt{s} = $ 14 TeV, it will acquire a ten times larger statistics respect to Run II, in order to have precise measurements of $\pi^{0}$ production; operating in high energy p-O and O-O collisions, it will measure forward production in a configuration that is very similar to the first interaction of an Ultra High Energy Cosmic Ray with an atmospheric nucleus. The FASER experiment is dedicated to the search of new weakly-interacting light particles, thanks to a forward detector with proper shielding from Standard Model background. In Run III, the experiment will search for new particles with a good sensitivity, which can be strongly improved by a following possible upgrade before HL-LHC. In addition, thanks to the dedicated FASER$\nu$ detector, the experiment will measure neutrino production at a collider for the first time. In this contribution, we discuss the main results expected from the LHCf and FASER experiments in Run III, highlighting their fundamental contribution in research fields that are not accessible to the four large LHC experiments.