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标题：On the determination of low-energy constants for Delta S=1 transitions
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作者：L. Giusti ; C. Pena ; P. Hernandez 等
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2005
卷号：2005
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present our preliminary results for three-point correlation functions involving the operators entering the DS = 1 effective Hamiltonian with an active charm quark, obtained using overlap fermions in the quenched approximation. This is the first computation carried out for valence quark masses small enough so as to permit a matching to Quenched Chiral Perturbation Theory in the e -regime. The commonly observed large statistical fluctuations are tamed by means of lowmode averaging techniques, combined with restrictions to individual topological sectors. We also discuss the matching of the resulting hadronic matrix elements to the effective low-energy constants for DS = 1 transitions. This involves (a) finite-volume corrections which can be evaluated at NLO in Quenched Chiral Perturbation Theory, and (b) the short-distance renormalization of the relevant four-quark operators in discretizations based on the overlap operator. We discuss perturbative estimates for the renormalization factors and possible strategies for their non-perturbative evaluation. Our results can be used to isolate the long-distance contributions to the DI = 1/2 rule, coming from physics effects around the intrinsic QCD scale.