The Capture Probability of Negative Mesotrons

Disintegration curves of positive and negative mesotrons stopping in ${\mathrm{H}}_2$O, NaF, Mg, Al, and S have been determined. The relative counting rates of positive and negative disintegration electrons support the view that the change of the mean life of negative mesotrons can be interpreted as due to a competition between the processes of spontaneous disintegration and nuclear capture. The mean-life values of positive mesotrons in the various materials are in agreement and yield a mean of ${\tau }_{+}=2.11\mathrm{}\pm 0.10$ μsec. From the mean life values of negative mesotrons the capture probabilities of mesotrons in the neighborhood of the absorber nuclei are calculated and shown to obey an empirical law of the form $k{Z}^a$ with a = 3.7±0.85.