We discuss the implementation and properties of the quenched approximation in the calculation of the left-right, strong penguin contributions (i.e. Q6) to ′/. The coefficient of the new chiral logarithm, discovered by Golterman and Pallante, which appears at leading order in quenched chiral perturbation theory is evaluated using both the method proposed by those authors and by an improved approach which is free of power divergent corrections. The result implies a large quenching artifact in the contribution of Q6 to ′/. This failure of the quenched approximation affects only the strong penguin operators and so does not affect the Q8 contribution to ′/ nor ReA0, ReA2 and thus, the ΔI=1/2 rule at tree level in chiral perturbation theory.
|Original language||English (US)|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|State||Published - 2006|
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)