Determination of the Delta S = 1 weak Hamiltonian in the SU(4) chiral limit through topological zero-mode wave functions
Feb, 2008
38 pages
Published in:
- JHEP 05 (2008) 043
e-Print:
- 0802.3591 [hep-lat]
Report number:
- BI-TP-2008-04,
- EDINBURGH-2008-07,
- FTUAM-08-01,
- FTUV-08-0226,
- IFIC-08-07,
- IFT-UAM-CSIC-08-07,
- MKPH-T-08-01
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Abstract: (arXiv)
A new method to determine the low-energy couplings of the weak Hamiltonian is presented. It relies on a matching of the topological poles in of three-point correlators of two pseudoscalar densities and a four-fermion operator, measured in lattice QCD, to the same observables computed in the -regime of chiral perturbation theory. We test this method in a theory with a light charm quark, i.e. with an SU(4) flavour symmetry. Quenched numerical measurements are performed in a 2 fm box, and chiral perturbation theory predictions are worked out up to next-to-leading order. The matching of the two sides allows to determine the weak low-energy couplings in the SU(4) limit. We compare the results with a previous determination, based on three-point correlators containing two left-handed currents, and discuss the merits and drawbacks of the two procedures.- lattice field theory
- two-point function
- n-point function: 3
- density: pseudoscalar
- operator: (4 fermion)
- perturbation theory: chiral
- symmetry: SU(4)
- zero mode: wave function
- low-energy constant
- numerical calculations
References(47)
Figures(11)