Consequence of High-Energy Neutrino Experiment on the Lepton Number Conservation Law

Using the quoted μ⁺-to-μ^- ratio obtained from the Berne-CERN-Fribourg neutrino experiment, the upper limit of CM was estimated to be of the order of 5CV, where CV is the universal vector-coupling constant of β decay, and CM characterizes the coupling strength of a four-fermion weak interaction vertex only allowed by a multiplicative lepton-number conservation law.