出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The transformation properties of strong penguin operators under the action of the flavor group
change when they are considered as operators in (partially) quenched QCD instead of the unquenched
theory. An ambiguity arises, which is parameterized by new low-energy constants in
the effective theory describing non-leptonic kaon decays in the (partially) quenched setting. Here
we summarize results of the analysis for the complete set of three-flavor strong penguin operators,
consisting of products of two left-handed flavor currents, or a left- and a right-handed current. Our
results imply that (partially) quenched lattice computations of the DI =1/2 rule and e0/e are both
affected by ambiguities intrinsic to the use of the quenched approximation at leading order in the
chiral expansion. The only exception is the partially quenched case with three light sea quarks,
consistent with general expectations. We also address the issue of quenched ambiguities in the
case of an active charm, correcting and extending that in Phys. Rev. D 74, 014509 (2006).
