Proof-of-principle demonstration of muon production with an ultrashort high-intensity laser

Muons play a crucial role in both fundamental and applied physics. Traditionally, they have been generated from cosmic rays or with proton accelerators. With the advent of ultrashort high-intensity lasers capable of accelerating electrons to gigaelectronvolt energies, muons can also be produced in laser laboratories. Here we report a proof-of-principle experiment of muon production. We accelerated an electron beam to gigaelectronvolt energies with an ultrashort, high-intensity laser pulse and passed the beam through a lead converter target in which muons were generated. We confirmed the muon signal by measuring its lifetime. We investigated the photo-production, electro-production and Bethe–Heitler processes underlying muon generation and their subsequent detection with Geant4 simulations. The results show that the dominant contribution stems from photo-production and electro-production. We estimate that a muon yield of up to 0.01 muon per incoming electron could be achieved in the converter target. This laser-driven muon source features compact, ultrashort pulses and high flux. Moreover, its implementation in a small laser laboratory is relatively straightforward, which dramatically reduces barriers for research in areas such as muonic X-ray elemental analysis or muon spin spectroscopy. Muons are conventionally produced from cosmic rays or with a proton accelerator. Now a proof-of-principle experiment demonstrates the feasibility of muon production with a laser-driven electron beam with gigaelectronvolt energy in a lead converter target.