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Open Access item K -> π π amplitudes from lattice QCD with a light charm quark

Authors:Giusti, Leonardo
Hernández Gamazo, Pilar
Laine, M.
Pena, Carlos Roberto
Wennekers, J.
Wittig, H.
Keywords:Chiral perturbation theory, To-leading order, Weak interactions, Wilson fermions, [PACS] Lattice QCD calculations, [PACS] Hadronic decays of K mesons, [PACS] Chiral symmetries in particles and fields
Issue Date:23-Feb-2007
Publisher:American Physical Society
Citation:Physical Review Letters 98: 082003 (2007)
Series/Report no.:IFIC/06-17
Abstract:We compute the leading-order low-energy constants of the ΔS=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 ΔI = 1/2 enhancement in this corner of the parameter space of the theory. Although matching with the experimental result is not observed for the Δ = 1/2 amplitude, our computation suggests large QCD contributions to the physical ΔI = 1/2 rule in the GIM limit, and represents the first step to quantify the role of the charm-quark mass in K -> π π amplitudes. The use of fermions with an exact chiral symmetry is an essential ingredient in our computation.
Description:4 pages, 1 figure.-- PACS nrs.: 12.38.Gc, 13.25.Es, 11.30.Rd.-- ISI Article Identifier: 000244420700019.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0607220
Publisher version (URL):http://dx.doi.org/10.1103/PhysRevLett.98.082003
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