标题： 冻结的企鹅，Delta I=1/2规则，epsilon'/epsilon 显示英文标题

标题： Quenched penguins, the Delta I=1/2 rule, and epsilon'/epsilon

摘要： 强penguin算符在味群作用下的变换性质，当它们被考虑为(部分)消去QCD中的算符而不是未消去理论中的算符时会发生变化。 出现了一种歧义，这种歧义由描述(部分)消去设置中非轻子K介子衰变的有效理论中的新低能常数来参数化。 在这里，我们总结了对包含两个左手味流或一个左手和一个右手流的乘积的完整三味强penguin算符集的分析结果。 我们的结果表明，(部分)消去格点计算Delta I=1/2规则和epsilon'/epsilon都受到在手征展开中领先阶使用消去近似固有歧义的影响。 唯一的例外是具有三个轻海夸克的部分消去情况，这与一般预期一致。 我们还讨论了在存在活跃魅夸克情况下的消去歧义，修正并扩展了Phys. Rev. D 74, 014509 (2006)中的相关内容。 显示英文摘要

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 Delta I=1/2 rule and epsilon'/epsilon 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).