Measurements of the Muon Lifetime with Cosmic Ray Muon Telescopes: A Novel Muon Lifetime Experiment

In our undergraduate laboratory, students use muon telescopes to measure paths of cosmic ray muons close to the earth, and a separate apparatus to measure the muon lifetime. We've designed a new SiPM-scintillator-based muon telescope capable of measuring both lifetime and angle dependence (for details on cosmic ray shower detection using an array of these muon telescopes, see the talk by Zachary Huseman). The muon lifetime is determined by measuring the time between double pulses, one indicating a muon arrival and the other a subsequent decay. As of October 2025, our measurement of the muon lifetime is 1.93 ± 0.05 µs. Discrepancies from the accepted value of about 2.20 µs are likely due to small systematic errors which we are investigating. Data suggests that these telescopes (at a total cost of $250 per telescope) can accurately run the muon lifetime experiment, providing undergraduate students with valuable lessons in quantum mechanics, digital circuits, and particle physics.