Δ degrees of freedom in trinuclei. V. Exotic contributions

Abstract

Three-body channels constructed from two-body N\ensuremath{\Delta} and \ensuremath{\Delta}\ensuremath{\Delta} states with non-nucleonic JT\ensuremath{\pi} values (J,T, and \ensuremath{\pi} denote conserved angular momentum, isospin, and parity, respectively) appear in the three-body Faddeev equation. The effects of such ``exotic'' channels on the triton binding energy (${\mathit{E}}_{\mathit{T}}$) are studied here for the first time, using the Argonne V28 \ensuremath{\Delta} model. Two types of exotic JT\ensuremath{\pi} sectors are distinguished: ``Pauli exotic'' sectors from which NN channels are absent due to the Pauli principle and spin considerations, and ``isospin exotic'' sectors which have the non-nucleonic value (T=2) of the two-body isospin. Pauli exotic contributions to ${\mathit{E}}_{\mathit{T}}$ are found to yield about 90 keV of repulsion, while isospin exotics add another 55 keV to this figure, for a total effect of about 145 keV. Exotic effects thus only slightly modify our previous V28-model result for ${\mathit{E}}_{\mathit{T}}$ based on nonexotic NNN, NN\ensuremath{\Delta}, N\ensuremath{\Delta}\ensuremath{\Delta}, and \ensuremath{\Delta}\ensuremath{\Delta}\ensuremath{\Delta} configurations, moving it from about 7.29 MeV down to about 7.14 MeV. This worsens the triton binding energy defect to about 1.5 MeV. Exotic effects are further decomposed and overall implications are discussed as well.