Analytic estimates of quenched penguins

TL;DR

This paper provides analytic estimates of the effects of quenching on the strong penguin operator Q_6, revealing significant impacts due to the non-singlet nature in the quenched theory.

Contribution

It introduces analytic estimates for low-energy constants of the quenched penguin operator, highlighting the large effects of quenching.

Findings

Quenching causes the operator to lose its singlet property.

More low-energy constants are needed in the quenched theory.

Quenching significantly affects the behavior of the penguin operator.

Abstract

When we embed the strong penguin operator Q_6 in the quenched theory, it does not remain a singlet under right-handed chiral transformations. As a consequence, more low-energy constants associated with this operator appear than in the unquenched theory. We give analytic estimates of the leading constants. The results suggest that the effects of quenching on this operator are large.