Pion-assisted Nucleon-Delta and Delta-Delta dibaryons

Abstract

N-Delta and Delta-Delta dibaryon candidates are discussed and related quark-based calculations are reviewed. New hadronic calculations of L=0 nonstrange dibaryon candidates are reported. For N-Delta, I(JP)=1(2+) and 2(1+) S-matrix poles slightly below threshold are found by solving pi-N-N Faddeev equations with relativistic kinematics, and for Delta-Delta several S-matrix poles below threshold are found by solving pi-N-Delta Faddeev equations with relativistic kinematics in which the N-Delta interaction is dominated by the 1(2+) and 2(1+) resonating channels. In particular, the I(JP)=0(3+) Delta-Delta dibaryon candidate D_{03}(2370) observed recently by the WASA@COSY Collaboration is naturally explained in terms of long-range physics dominated by pions, nucleons and Delta's. These calculations are so far the only ones to reproduce the relatively small width, approximately 70 MeV, of D_{03}(2370). Predictions are also made for the location and width of D_{30}, the I(JP)=3(0+) exotic partner of D_{03}(2370).