  Within the standard V - A theory of weak interactions, Quantum
Electrodynamics (QED) and the linear sigma-model (LsM) of strong low-energy
hadronic interactions we analyse infrared properties of hadronic structure of
the neutron and proton in the neutron beta decays to leading order in the large
nucleon mass expansion. We confirm validity and high confidence level of
contributions of hadronic structure of the nucleon to the radiative
corrections, calculated by Sirlin (Phys. Rev. 164, 1767 (1967)) to leading
order in the large nucleon mass expansion. At the level of order 10^{-5}
relative to Sirlin's infrared divergent contribution to the neutron radiative
beta decay (inner bremsstrahlung) we find an infrared divergent contribution,
induced by hadronic structure of the nucleon through the one-pion-pole
exchange, to the rate of the neutron lifetime from the neutron radiative beta
decay, which should be cancelled by contributions of virtual photon exchanges
to the neutron beta decay. Following Ivanov et al. 1805.09702 [hep-ph] we argue
that a consistent analysis of such a cancellation may be carried out well in
the combined quantum field theory including the Standard Electroweak Model
(SEM) and the LsM of strong low-energy interactions, where the effective V - A
hadron-lepton current-current vertex is caused by the W^- - electroweak-boson
exchange.
