Two-body spectra of pseudoscalar mesons with an O(a2)-improved lattice action using Wilson fermions

Abstract

We extend our calculations with the second-order tree-level and tadpole improved next-nearest-neighbor action to meson-meson systems. Correlation matrices built from interpolating fields representing two pseudoscalar mesons (π-π) with relative momenta p are diagonalized, and the mass spectrum is extracted. Link variable fuzzing and operator smearing at both sinks and sources is employed. Calculations are presented for two values of the hopping parameter. The spectrum is used to discuss the residual interaction in the meson-meson system.

On the I = 2 channel π-π interaction in the chiral limit

“…(The current lattice parameters should be better suited for studying interactions involving, larger sized, baryons.) In addition to V (r) there is also present a nonlocal potential [1] which not yet been computed.…”

“…An outline of the theoretical framework may be found in [1,7], we here mention only the essential points. Suitable operators for the π + -π + system, having isospin I = 2, are…”

“…This paper is a report on the current status of this project. An earlier exploratory study [1] was made with a smaller number of gauge configurations and two, somewhat large, quark masses. The new results presented here are based on 208 configurations and 6 values of quark masses, with otherwise unchanged lattice parameters.…”

Interactions between Lattice Hadrons

“…These are from a set of six values κ −1 which have been used to perform the chiral extrapolation m 2 π → 0 (equivalently κ → κ c ). The other lattice parameters [95] were L = 9, T = 13, and β = 6.2 with the next-nearest-neighbor o(a 2 ) tadpole-improved action [11,44]. The lattice constant, matched to the string tension, is a = 0.4 fm or a −1 = 500 MeV.…”