The charm-quark contribution to light-by-light scattering in the muon from lattice QCD.

We compute the hadronic light-by-light scattering contribution to the muon from the charm quark using lattice QCD. The calculation is performed on ensembles generated with dynamical (, , ) quarks at the SU(3) symmetric point with degenerate pion and kaon masses of around 415 MeV. It includes the connected charm contribution, as well as the leading disconnected Wick contraction, involving the correlation between a charm and a light-quark loop.

Weakly Bound H Dibaryon from SU(3)-Flavor-Symmetric QCD.

We present the first study of baryon-baryon interactions in the continuum limit of lattice QCD, finding unexpectedly large lattice artifacts. Specifically, we determine the binding energy of the H dibaryon at a single quark-mass point. The calculation is performed at six values of the lattice spacing a, using O(a)-improved Wilson fermions at the SU(3)-symmetric point with m_{π}=m_{K}≈420  MeV.