Prompt acceleration of a short-lifetime low-energy muon beam

An energetic muon beam is an attractive key to unlock new physics beyond the Standard Model—the lepton flavor violation or the anomalous magnetic moment—and is also a competitive candidate for expected neutrino factories. Muon scientific applications are limited by low flux cosmic-ray muons, low energy muon sources, or extremely expensive muon accelerators. The prompt acceleration of a low-energy muon beam is found in a plasma wakefield driven by an electron beam. A muon beam can be accelerated from 275 MeV to more than 10 GeV within 22.5 ps in this wakefield. Choosing the proper time delay between the driving electron beam and the muon beam injected into the plasma, the longitudinal size of the muon beam and the energy dispersion of the muon beam are compressed. The efficiency of the energy transfer from the driving electron beam to the muon beam can reach 20%. This prompt acceleration is a promising avenue to bring expected neutrino factories and muon colliders into reality and to catch new physics beyond the Standard Model.