TY - JOUR
ID - Digital.CSIC
A1 - Giusti, Leonardo
A1 - Hernández Gamazo, Pilar
A1 - Laine, M.
A1 - Pena, Carlos Roberto
A1 - Wennekers, J.
A1 - Wittig, H.
Y1 - 2007-02-23
SN - 0031-9007
UR - http://hdl.handle.net/10261/9153
N2 - We compute the leading-order low-energy constants of the ?S=1 effective weak Hamiltonian in the quenched approximation of QCD with up, down, strange, and charm quarks degenerate and light. They are extracted by comparing the predictions of finite-volume chiral perturbation theory with lattice QCD computations of suitable correlation functions carried out with quark masses ranging from a few MeV up to half of the physical strange mass. We observe a ?I = 1/2 enhancement in this corner of the parameter space of the theory. Although matching with the experimental result is not observed for the ? = 1/2 amplitude, our computation suggests large QCD contributions to the physical ?I = 1/2 rule in the GIM limit, and represents the first step to quantify the role of the charm-quark mass in K -> ? ? amplitudes. The use of fermions with an exact chiral symmetry is an essential ingredient in our computation.
PB - American Physical Society
KW - Chiral perturbation theory
KW - [PACS] Chiral symmetries in particles and fields
KW - [PACS] Hadronic decays of K mesons
KW - [PACS] Lattice QCD calculations
KW - To-leading order
KW - Weak interactions
KW - Wilson fermions
T1 - K -> ? ? amplitudes from lattice QCD with a light charm quark
ER -