Vertex Clothing in Quantum Field Theory

The problem of the vertex renormalization in quantum field theory is tackled via the implementation of the unitary clothing transformation method. In the model of charged spinless nucleon and scalar meson fields coupled by the Yukawa-type three-linear interaction the expression for the charge correction in the first non-vanishing (third) order in the coupling constant is derived. Being the off-energy-shell quantity, the expression can be brought to the explicitly covariant form on the energy shell, providing the momentum independence of the charge renormalization