Potentials between pairs of static-light mesons

Abstract

We give an update on our ongoing investigations of potentials between pairs of static-light mesons, B(r)B(0) and B(r)B(0), in N f = 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 ≈ 0.084 fm and a ≈ 0.077 fm with a pseudoscalar mass of m PS ≈ 770 MeV and m PS ≈ 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.