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.
