Related papers: Chiral Perturbation Theory and Weak Matrix Element…
We propose a general method to obtain accurate estimates for some of the "low-energy constants" in the one-loop effective chiral Lagrangian by means of simulating lattice QCD. In particular, the method is sensitive to those constants whose…
This talks contains a short introduction to Chiral Perturbation Theory and the existing calculations to two-loop order in the mesonic sector. I include a discussion on which quantities the expansion can be organized in. The present best…
We investigate the chiral extrapolation of the lattice data for the light-heavy meson hyperfine splittings D^*-D and B^*-B to the physical region for the light quark mass. The chiral loop corrections providing non-analytic behavior in m_\pi…
We present our preliminary results for three-point correlation functions involving the operators entering the $\Delta{S}=1$ effective Hamiltonian with an active charm quark, obtained using overlap fermions in the quenched approximation.…
The ultraviolet behaviour of the generating functional for hadronic weak interactions with $|\Delta S| =1, 2$ is investigated to one loop for a generic number of flavours and in the quenched approximation. New quenched chiral logarithms…
I describe recent progress towards a theory of the NN force which captures the consequences of QCD's chiral symmetry and the pattern of its breaking, and is formulated as an expansion in a ratio of low and high mass scales, M_{lo}/M_{hi}.…
The parametric error on the QCD-coupling can be a dominant source of uncertainty in several important observables. One way to extract the coupling is to compare high order perturbative computations with lattice evaluated moments of heavy…
Heavy quark symmetry predicts the value of $B \rightarrow D$ and $B \rightarrow D^*$ transition matrix elements of the current $\bar c \gamma_\mu (1 - \gamma_5)b$, at zero recoil (where in the rest frame of the $B$ the $D$ or $D^*$ is also…
This paper presents a first study of the decay constants of the charged, or flavor-off-diagonal, pseudoscalar mesons to two loops for three flavors of sea quarks, in Partially Quenched Chiral Perturbation Theory (PQ$\chi$PT). Explicit…
[This version is a minor revision of a previously submitted preprint. Only references have been changed.] We describe a technique for constructing the effective chiral theory for quenched QCD. The effective theory which results is a…
We present decay constants from a quenched simulation using both propagating quarks and the static theory at $\beta=6.2$ on $24^3\times48$. The results using propagating quarks are used to test scaling laws predicted by the heavy quark…
The comparison of chiral perturbation theory formulae with data from lattice QCD simulations is discussed. Observables in the pion sector as well as in the baryon sector are considered, including the nucleon mass in a finite volume.
After a short status report on chiral perturbation theory, I review recent progress in determining some of the low-energy couplings by matching the effective theory to QCD. Consequences for K_{l3} decays and for the extraction of the CKM…
An examination of the symmetries manifest in the QCD path integral for current matrix elements reveals various equalities among the quark sector contributions. QCD equalities among octet baryon magnetic moments lead to a determination of…
We present the first investigation of the extrapolation of quenched nucleon magnetic moments in quenched chiral effective field theory. We utilize established techniques in finite-range regularisation and compare with standard dimensional…
We calculate the kaon B-parameter, B_K, to next-to-leading order in staggered chiral perturbation theory. We find expressions for partially quenched QCD with three sea quarks, quenched QCD, and full QCD with m_u = m_d but not equal to m_s.…
Recently, we pointed out that chiral transformation properties of penguin operators change in the transition from unquenched to (partially) quenched QCD. As a consequence, new operators appear in (partially) quenched QCD penguins,…
We analyze how the recent precise hadronic tau-decay data on the V-A spectral function and general properties of QCD such as analyticity, the operator product expansion and chiral perturbation theory (ChPT), can be used to improve the…
We calculate the divergences of the generating functional of quenched Chiral Perturbation Theory to one loop for a generic number of flavours. The flavour number dependence of our result enlightens the mechanism of quark loop cancellation…
We calculate the effects of including dynamical fermion loops in the lattice QCD estimates of meson decay constants, by extrapolating the results from negative flavour numbers after a suitable matching of the pion and rho mass. For…