Two-meson cloud contribution to the baryon antidecuplet binding

Abstract

We study the two-meson virtual cloud contribution to the self-energy of the SU(3) antidecuplet, to which the Theta+ pentaquark is assumed to belong. This is motivated by the large branching ratio of the N(1710) decay into two pions and one nucleon. We derive effective Lagrangians that describe the N(1710) decay into N-pi-pi with two pions in s or p wave. We obtain increased binding for all members of the antidecuplet and a contribution to the mass splitting between states with different strangeness which is at least 20 % of the empirical one. We also provide predictions for three-body decays of the pentaquark antidecuplet.