Tbbb: A three B-meson bound state

By solving exactly the Faddeev equations for the bound-state problem of three mesons, we demonstrate that current theoretical predictions pointing to the existence of a deeply-bound doubly bottom axial vector tetraquark lead to the existence of a unique bound state of three B mesons. We find that the BB⁎B⁎−B⁎B⁎B⁎ state with quantum numbers (I)JP=(1/2)2−, Tbbb, is about 90 MeV below any possible three B-meson threshold for the reported binding of the doubly bottom axial vector tetraquark, Tbb.