¥The original muon
lifetime was measured by Rossi and Hall by comparing the muon absorption of air
and dense absorbers (with equivalent stopping powers).
¥The previously observed
anomalous stopping of muons in air was assumed to be due to the decay of
muons.
¥Based on carefully
measured muon rates at different altitudes, with and without absorbers, Rossi
and Hall obtained a lifetime of 2.4 ± 0.3 µs.