The method of unitary clothing transformations is applied in the model involving nucleon and neutral pion fields interacting via the regularized pseudoscalar Yukawa-type coupling. In this approach the mass counterterms are cancelled (at least, partly) by commutators of the generators of clothing transformations and the field interaction operator forming the pion and nucleon mass shifts expressed through the corresponding three-dimensional integrals whose integrands depend on certain covariant combinations of the relevant three-momenta. The property provides the momentum independence of mass renormalization. The conditions imposed upon the cutoff vertex function are specified. PACS: 21.45.+v; 24.10. Jv; 11.80.-m 1. FIELD MODEL WITH REGULARIZED INTERACTION Our departure point is the Hamiltonian () () () 0 0 F I H H H α α = + 0 α 0 α k  ) () () () () 0 0 0 F r e n r e n H M V V α α α = + + + , (1) where-set of all creation and destruction operators of the "bare" particles with physical masses and coup-ing constants [1]. In case of a spinor (fermion) field and a neutral pseudoscalar (meson) field one has 0 α () () † 0 () F H d a a α ω = ∫ k k k () () () () † † , , , , r d E b r b r d r d r  + +  ∑ ∫ p p p p p p , (2) with the operators for mesons , nucleons b r , antinucleons and their adjoint counterparts. The quantities , and are the particle momenta and the fermion polarization index. Relativistic physical energies are expressed as () a k () , p (, d r p p k r 2 E = p 2 m + p and 2 , − 2 µ + () 0 α 2 µ ω = k k ren ferm M + 2 2 0 δµ µ = , where and play role of physical (renormalized) masses. are usual mass counterterms for mesons and fermions, containing respective mass shifts and where and play role of trial (unrenormalized) masses. The one-particle operators in (2) satisfy the usual commutation relations m µ ren m − ()) 0 , ren M M = 0 m (mes α α 0 µ 0) ′ − p) , −. c ,r 0 m m = δ () () †

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We obtained a nonrelativistic deuteron wave function that accounts for the D-state and has correct asymptotic behavior. This was achieved on the basis of the experimentally measured charge and quadrupole deuteron form factors. The differential cross section of the elastic deuteron-nucleus scattering has been calculated by using this wave function. These predictions agree with the experimental data at the energy of 110 MeV. The integrated cross sections of the various processes involving the deuteron-nucleus interactions were also calculated.

The approach which enables to obtain the solutions of the variational equation as the series [Formula: see text] is considered. It is shown that when N=1 it gives well-known cos x solutions, while for N>1 it leads to essentially nonlinear functions. The φ2φ′2-term in the thermodynamical potential provides the proper nonlinear behavior of the order parameter and the possibility of existence of kink-like distributions, particularly. In special case N=2 there exist the exact partial solutions which, however, do not give the absolute minima to the thermodynamical potential.

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