1305.4462 (T. Kurth et al.)

Phase shifts in I=2 ππ-scattering from two lattice approaches    [PDF]

T. Kurth, N. Ishii, T. Doi, S. Aoki, T. Hatsuda

We present a lattice QCD study of the phase shift of I=2 {\pi}{\pi}-scattering on the basis of two different approaches: the standard finite volume approach by Luscher and the recently introduced HAL QCD potential method. Quenched QCD simulations are performed on a 32^3x128 lattice with lattice spacing a 0.115 fm using a heavy pion mass of m_{\pi} 940 MeV. Results of the phase shift and the scattering length are shown to agree quite well between these two methods. In case of the potential method, the error is dominated by the systematic uncertainty associated with the violation of rotational symmetry due to finite lattice spacing. In Luscher's approach, such systematic uncertainty is difficult to be evaluated and thus not included in this work. In case of the potential method, the phase shift can be calculated for arbitrary energies below the inelastic threshold. In that context, the phase shift obtained from the nonrest-frame extension of Luscher's method obtained at a particular center-of-mass momentum lies on top of the curve predicted by the potential method.

View original: http://arxiv.org/abs/1305.4462