Lattice QCD study on $K^{\ast }(892)$ meson decay width

Abstract

We deliver an exploratory lattice QCD examination of the $K^{\ast }(892)$ meson decay width with the help of the p-wave scattering phase ${\delta }_1$ of pion-kaon ($\pi K$) system in the isospin $I=1/2$ channel, which are extracted by the modified Rummukainen-Gottlieb formula for two-particle system with arbitrary mass, and it clearly reveals the entity of a resonance at a mass around $K^{\ast }(892)$ meson mass. The effective range formula is applied to describe the energy dependence of the scattering phase and we obtain the effective $K^{\ast }\to \pi K$ coupling constant as $g_{K^{\ast }\pi K}=6.38(78)$, and subsequently achieve the decay width to be $64.9\pm 8.0$ MeV, which is in reasonable accordance with the current experiment. Our lattice investigations are conducted on a $20^3\times 48$ MILC full QCD gauge configuration at $(m_{\pi }+m_K)/m_{K^{\ast }}\approx 0.739$ and the lattice spacing $a\approx 0.15$ fm.

Comments: Correct some typos and replace some figures with high quality ones