Dybaryon model for nuclear force and the properties of the 3N system

The dibaryon model for NN interaction, which implies the formation of an intermediate six-quark bag dressed by a σ field, is applied to the 3N system, where it results in a new three-body force of scalar nature between the six-quark bag and a third nucleon. A new multicomponent formalism is developed to describe three-body systems with nonstatic pairwise interactions and non-nucleonic degrees of freedom. Precise variational calculations of 3N bound states are carried out in the dressed-bag model including the new scalar three-body force. The unified coupling constants and form factors for 2N- and 3N-force operators are used in the present approach, in a sharp contrast to conventional meson-exchange models. It is shown that this three-body force gives at least half the 3N total binding energy, while the weight of non-nucleonic components in the 3H and 3He wavefunctions can exceed 10%. The new force model provides a very good description of 3N bound states with a reasonable magnitude of the σNN coupling constant. A new Coulomb 3N force between the third nucleon and dibaryon is found to be very important for a correct description of the Coulomb energy and r.m.s. charge radius in 3He