K+→π+π0 decay amplitude with the Wilson quark action in quenched lattice QCD

JLQCD Collaboration

Aoki S

Fukugita M

Hashimoto S

Ishizuka N

Iwasaki Y

Kanaya K

Kuramashi Y

Okawa Masanori

Ukawa A

Yoshié T

Physical Review D

We present a calculation for the K+→π+π0 decay amplitude using a quenched simulation of lattice QCD with the Wilson quark action at β=6/g2=6.1. The decay amplitude is extracted from the ratio, the K→ππ three-point function divided by either K and π meson two-point functions or K meson two-point function and I=2 ππ four-point function; the two different methods yield consistent results. Finite size effects are examined with calculations made on 243×64 and 323×64 lattices, and are shown that they are explained by one-loop effects of chiral perturbation theory. The lattice amplitude is converted to the continuum value by employing a one-loop calculation of chiral perturbation theory, yielding a value in agreement with experiment if extrapolated to the chiral limit. We also report on the K meson B parameter BK obtained from the K+→π+π0 amplitude using chiral perturbation theory.

Physics [ 420 ]

eng

The American Physical Society

Copyright (c) 1998 The American Physical Society

[ISSN] 1550-7998

[DOI] http://dx.doi.org/10.1103/PhysRevD.58.054503 isVersionOf