Published online by Cambridge University Press: 25 April 2016
A recent measurement of muon flux at energies greater than 1012 eV provides evidence for muon production by a process other than pion decay in cosmic-ray showers. Near this characteristic energy, the existing theory of weak interactions requires modification if it is not to violate a limitation (2) imposed by unitarity, which represents the conservation of probability. This work is an examination of modifications that are needed if the framework (4) of the theory is to be retained.