Deuteronlike Heavy Dibaryons from Lattice Quantum Chromodynamics

Strongly Bound Dibaryon with Maximal Beauty Flavor from Lattice QCD

We report the first lattice QCD study of the heavy dibaryons in which all six quarks have the bottom (beauty) flavor. Performing a state-of-the-art lattice QCD calculation we find clear evidence for a deeply bound Ω_{bbb}-Ω_{bbb} dibaryon in the ^{1}S_{0} channel, as a pole singularity in the S-wave Ω_{bbb}-Ω_{bbb} scattering amplitude with a binding energy -81( _{-16}^{+14})  MeV. With such a deep binding, Coulomb repulsion serves only as a perturbation on the ground state wave function of the parametrized strong potential and may shift the strong binding only by a few percent. Considering the scalar channel to be the most bound for single flavored dibaryons, we conclude this state is the heaviest possible most deeply bound dibaryon in the visible universe.

QCD confronts heavy-flavor and exotic hadrons

A review of QCD-based theory approaches to study the heavy-flavor and exotic hadrons is given. The focus is on the results from lattice QCD and from lattice QCD complemented by effective field theories. Both approaches are first briefly introduced and applied in few examples. Then the status of various hadrons sectors is presented.

Dibaryon with Highest Charm Number near Unitarity from Lattice QCD

A pair of triply charmed baryons, Ω_{ccc}Ω_{ccc}, is studied as an ideal dibaryon system by (2+1)-flavor lattice QCD with nearly physical light-quark masses and the relativistic heavy-quark action with the physical charm quark mass. The spatial baryon-baryon correlation is related to their scattering parameters on the basis of the HAL QCD method. The Ω_{ccc}Ω_{ccc} in the ^{1}S_{0} channel, taking into account the Coulomb repulsion with the charge form factor of Ω_{ccc}, leads to the scattering length a_{0}^{C}≃-19  fm and the effective range r_{eff}^{C}≃0.45  fm. The ratio r_{eff}^{C}/a_{0}^{C}≃-0.024, whose magnitude is considerably smaller than that of the dineutron (-0.149), indicates that Ω_{ccc}Ω_{ccc} is located in the unitary regime.

Very Heavy Flavored Dibaryons

We explore the possibility of very heavy dibaryons with three charm quarks and three beauty quarks, bbbccc, using a constituent model which should lead to the correct solution in the limit of hadrons made of heavy quarks. The six-body problem is treated rigorously, in particular taking into account the orbital, color, and spin mixed-symmetry components of the wave function. Unlike a recent claim based on lattice QCD, no bound state is found below the lowest dissociation threshold.