Exotic dibaryons with a heavy antiquark

Abstract

We discuss the possible existence of exotic dibaryons with a heavy antiquark, being realized as three-body systems,D ( * ) NN and B ( * ) NN. These are genuinely exotic states with no quark-antiquark annihilation. We consider the heavy quark spin and chiral symmetries, and introduce the one pion exchange potential between aD ( * ) (B ( * ) ) meson and a nucleon N. As for the NN interaction, we employ the Argonne v ′ 8 potential. By solving the coupled-channel equations for P NN and P * NN (P ( * ) =D ( * ) and B ( * ) ), we find bound states for (I, J P ) = (1/2, 0 − ) as well as resonant states for (I, J P ) = (1/2, 1 − ) both inD ( * ) NN and B ( * ) NN systems. We also discuss the heavy quark limit, and find that the spin degeneracy is realized in the bound states with (I, J P ) = (1/2, 0 − ) and (1/2, 1 − ).