Results of a high-statistics, multivolume lattice QCD exploration of the deuteron, the dineutron, the H-dibaryon, and the ${\Xi }^{-}{\Xi }^{-}$ system at a pion mass of $m_{\pi }\sim 390\mathrm{MeV}$ are presented. Calculations were performed with an anisotropic $n_f=2+1$ clover discretization in four lattice volumes of spatial extent $L\sim 2.0$, 2.5, 2.9, and 3.9 fm, with a lattice spacing of $b_s\sim 0.123\mathrm{fm}$ in the spatial direction and $b_t\sim b_s/3.5$ in the time direction. Using the results obtained in the largest two volumes, the ${\Xi }^{-}{\Xi }^{-}$ is found to be bound by $B_{{\Xi }^{-}{\Xi }^{-}}0=14.0(1.4)(6.7)\mathrm{MeV}$, consistent with expectations based upon phenomenological models and low-energy effective field theories constrained by nucleon-nucleon and hyperon-nucleon scattering data at the physical light-quark masses. Further, we find that the deuteron and the dineutron have binding energies of $B_d=11(05)(12)\mathrm{MeV}$ and $B_{nn}=7.1(5.2)(7.3)\mathrm{MeV}$, respectively. With an increased number of measurements and a refined analysis, the binding energy of the H-dibaryon is $B_H=13.2(1.8)(4.0)\mathrm{MeV}$ at this pion mass, updating our previous result.

• Received 15 September 2011

DOI:https://doi.org/10.1103/PhysRevD.85.054511