Potentials between pairs of static-light mesons
  We give an update on our ongoing investigations of potentials between pairs of static-light mesons in Nf=2 Lattice QCD, in different spin and isospin channels. The question of attraction and repulsion is particularly interesting with respect to the X(3872) charmonium state and charged candidates such as the Z+(4430). We employ the nonperturbatively improved Sheikholeslami-Wohlert fermion and the Wilson gauge actions at two lattice spacings a approx. 0.084 fm and a approx. 0.077 fm with a pseudoscalar mass of mPS approx. 770 MeV and mPS approx. 400 MeV respectively. We use stochastic all-to-all propagator techniques, improved by a hopping parameter expansion. The analysis is based on the variational method, utilizing various source and sink interpolators. 
Gunnar Bali, Martin Hetzenegger
hep-lat