I = 2ππ scattering phase shift with two flavors of O(a) improved dynamical quarks

Abstract

We present a lattice QCD calculation of phase shift including the chiral and continuum extrapolations in two-flavor QCD. The calculation is carried out for I = 2 S-wave ππ scattering. The phase shift is evaluated for two momentum systems, the center of mass and laboratory systems, by using the finite-volume method proposed by Lüscher in the center of mass system and its extension to general systems by Rummukainen and Gottlieb. The measurements are made at three different bare couplings β = 1.80, 1.95 and 2.10 using a renormalization group improved gauge and a tadpole improved clover fermion action, and employing a set of configurations generated for hadron spectroscopy in our previous work. The illustrative values we obtain for the phase shift in the continuum limit are δ(deg.) = -3.50(64), -9.5(30) and -16.9(64) for √s(GeV) = 0.4, 0.6 and 0.8, which are consistent with experiments.