The Physics Case for an Electron-Muon Collider

Meng Lu,Jie Xiao,Tianyi Yang,Antonios Agapitos,Andrew Michael Levin,Sitian Qian,Qiang Li,Congqiao Li,Fanqiang Meng,Mariana Frank

doi:10.1155/2021/6693618

Abstract

An electron-muon collider with an asymmetric collision profile targeting multi-ab-1 integrated luminosity is proposed. This novel collider, operating at collision energies of, e.g., 20–200 GeV, 50–1000 GeV, and 100–3000 GeV, would be able to probe charged lepton flavor violation and measure Higgs boson properties precisely. The collision of an electron and muon beam leads to less physics background compared with either an electron-electron or a muon-muon collider, since electron-muon interactions proceed mostly through higher-order vector boson fusion and vector boson scattering processes. The asymmetric collision profile results in collision products that are boosted towards the electron beam side, which can be exploited to reduce beam-induced background from the muon beam to a large extent. With this in mind, one can imagine a lepton collider complex, starting from colliding order 10 GeV electron and muon beams for the first time in history and to probe charged lepton flavor violation, then to be upgraded to a collider with 50-100 GeV electron and 1-3 TeV muon beams to measure Higgs properties and search for new physics and finally to be transformed to a TeV-scale muon-muon collider. The cost should vary from order 100 million to a few billion dollars, corresponding to different stages, which make the funding situation more practical.

Highlights

The discovery [1, 2] and property measurements [3,4,5,6,7,8] of the Higgs boson are a triumph of the Standard Model (SM) of particle physics and the Large Hadron Collider (LHC)
The 2020 update of the European Strategy for Particle Physics [9] proposes a vision for both the near- and the long-term future of the field, highlighting the need to pursue, as the highest-priority facility after the LHC, an electron-electron collider acting as a Higgs factory, such as the proposed International Linear Collider (ILC), the Compact Linear Collider (CLIC), the Future Circular Collider (FCC), or the Circular Electron Positron Collider (CEPC)
Based on a realistic simulation at s = 1:5 TeV with beam-induced background (BIB) included, Ref. [17] found that the coupling between the Higgs boson and the b-quark can be measured at the percent level with order ab-1 of collected data

Summary

Introduction

The discovery [1, 2] and property measurements [3,4,5,6,7,8] of the Higgs boson are a triumph of the Standard Model (SM) of particle physics and the Large Hadron Collider (LHC). We propose an electron-muon collider with an asymmetric collision profile of, e.g., 20–200 GeV, 50–

Results

Conclusion