  Three-body hadronic models with separable pairwise interactions are
formulated and solved to calculate resonance masses and widths of L=0 N-Delta
and Delta-Delta dibaryons using relativistic kinematics. For N-Delta,
I(JP)=1(2+) and 2(1+) resonances slightly below threshold are found by solving
pi-N-N Faddeev equations. For Delta-Delta, several resonances below threshold
are found by solving pi-N-Delta Faddeev equations in which the N-Delta
interaction is dominated by the 1(2+) and 2(1+) resonating channels. The lowest
Delta-Delta dibaryon resonances found are for I(JP)=0(3+) and 3(0+), the former
agreeing well both in mass and in width with the relatively narrow D_{03}(2370)
resonance observed recently by the WASA-at-COSY Collaboration. Its spin-isospin
symmetric partner D_{30} is predicted with mass around 2.4 GeV and width about
80 MeV.
