Lattice QCD investigation of a doubly-bottom b b ud tetraquark with quantum numbers i (JP)=0 (1+) LATTICE QCD INVESTIGATION of A DOUBLY-BOTTOM b b ud ... LUKA LESKOVEC et al.

We use lattice QCD to investigate the spectrum of the bbud four-quark system with quantum numbers I(JP)=0(1+). We use five different gauge-link ensembles with 2+1 flavors of domain-wall fermions, including one at the physical pion mass, and treat the heavy b quark within the framework of lattice nonrelativistic QCD. Our work improves upon previous similar computations by considering in addition to local four-quark interpolators also nonlocal two-meson interpolators and by performing a Lüscher analysis to extrapolate our results to infinite volume. We obtain a binding energy of (-128±24±10) MeV, corresponding to the mass (10476±24±10) MeV, which confirms the existence of a bbud tetraquark that is stable with respect to the strong and electromagnetic interactions.