On the interaction of μ-mesons with matter at high energies

Summary  The production of penetrating showers at depths of 50 and 200 metres water equivalent by high energy μ-mesons has been studied with a counter hodoscope. The values of the cross-section found (in lead) for events of this kind are consistent with those expected assuming an electromagnetic interaction mechanism, according to which the penetrating showers can be initiated by the photoproduction of a π-meson or by a high energy recoil nucleon. The agreement between the measured and calculated cross-section is very good, if it is assumed that the total photonuclear cross-section, σγtot = 3·10−28 cm2/nucleon, remains unchanged even at the high energies concerned at the depths considered. Therefore it seems unnecessary to invoke a new interaction in order to explain the experimental results.