The role of Delta(1232) in two-pion exchange three-nucleon potential

In this paper we have studied the two-pion exchange three-nucleon potential (2 pi E-3NP) using an approximate SU(2) x SU(2) chiral symmetry of the str ong interaction. The off-shell pion-nucleon scattering amplitudes obtained from the Weinberg Lagrangian are supplemented with contributions from the w ell-known sigma-term and the Delta(1232) exchange. It is the role of the De lta-resonance in 2 pi E - 3NP, which we have investigated in detail in the framework of the Lagrangian field theory. The Delta-contribution is quite a ppreciable and, more significantly, it is dependent on a parameter Z which is arbitrary but has the empirical bounds \Z\ less than or equal to 1/2. We find that the Delta-contribution to the important parameters of the 2 pi E - 3NP depends on the choice of a value for Z, although the correction to t he binding energy of triton is not expected to be very sensitive to the var iation of Z within its bounds.