Beta decay in the field of electromagnetic wave and neutrino mass search

The results of the investigation of electromagnetic field effects on the process of beta decay are used for analyzing experimental data on direct neutrino mass search. It is shown that electromagnetic wave can affect beta spectrum by shifting its end point towards higher energy values region. The phenomenon is of purely classical nature and is connected with the electron acceleration in the radiation field. The magnetic fields of substantial strength exist in the setups for the neutrino mass precise measurement, thus the above field can arise due to the synchrotron radiation mechanism. The phenomenon under study can explain the observed anomalies in the spectrum of decay electrons, in particular the effect of 'negative neutrino mass squared'