# Searching for muonic forces with the ATLAS detector

## TL;DR

This paper proposes using the ATLAS detector at the HL-LHC as a muon fixed-target experiment to search for new muonic force carriers, leveraging the large muon sample and dual momentum measurements.

## Contribution

It introduces a novel analysis method utilizing the ATLAS calorimeter and dual muon momentum measurements to probe new muon-coupled forces, including those related to the muon g-2 anomaly.

## Key findings

- Comparable reach to other proposals in probing new forces
- Can explore parameter space relevant to muon g-2 anomaly
- Utilizes muons from W and Z decays for analysis

## Abstract

The LHC copiously produces muons via different processes, and the muon sample will be large at the high-luminosity LHC (HL-LHC). In this work we propose to leverage this large muon sample and utilize the HL-LHC as a muon fixed-target experiment, with the ATLAS calorimeter as the target. We consider a novel analysis for the ATLAS detector, which takes advantage of the two independent muon momentum measurements by the inner detector and the muon system. We show that a comparison of the two measurements, before and after the calorimeters, can probe new force carriers that are coupled to muons and escape detection. The proposed analysis, based on muon samples from $W$ and $Z$ decays only, has a comparable reach to other proposals. In particular, it can explore the part of parameter-space that could explain the muon $g-2$ anomaly.