Variation of the Rate of Decay of Mesotrons with Momentum

Abstract

In order to determine the dependence of the probability of decay on momentum, mesotrons with range between 196 and 311 g/${\mathrm{cm}}^2$ of lead and mesotrons with range larger than 311 g/${\mathrm{cm}}^2$ of lead were investigated separately. The softer group of mesotrons was found to disintegrate at a rate about three times faster than the more penetrating group, in agreement with the theoretical predictions based on the relativity change in rate of a moving clock. A new value of the proper lifetime of mesotrons of (2.4±0.3)×${10}^{-6\mathrm{}}$ sec. is determined, based upon measurements with particles with momentum of approximately 5×${10}^8$ ev/c.