Precise Study of Three-Nucleon Systems within a Representation without Explicit Use of the Isospin Formalism

A representation without explicit use of the isospin formalism is developed for the precise study of few-nucleon systems, and the advantages of the proposed approach are demonstrated. Using the example of three-nucleon systems with central exchange NN-interaction potentials of the general type, the complete equivalence is shown for the both approaches with and without the isospin formalism. The new systems of equations contain a less number of components as compared to the commonly used ones and are more suitable for precise study of few-nucleon systems, in particular, within variational approaches. Optimal variational schemes are developed with Gaussian basis, and the binding energies, r.m.s. radii, density distributions, formfactors, and pair correlation functions are calculated with a high and controlled precision for 3H and 3He nuclei.