Andreas S. Kronfeld

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We present the first lattice QCD calculation with realistic sea quark content of the D+-meson decay constant f(D+). We use the MILC Collaboration's publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). We obtain f(D+)=201+/-3+/-17 MeV, where the errors are statistical(More)
The study of flavorand CP -violation is a vital part of particle physics [1]. Often lattice QCD is needed to connect experimental measurements to the fundamental couplings of quarks, which, in the Standard Model, are elements of the CabibboKobayashi-Maskawa (CKM) matrix. Usually the test of CKM is drawn as a set of constraints on the apex of the so-called(More)
We present the first three-flavor lattice QCD calculations for D-->pilnu and D-->Klnu semileptonic decays. Simulations are carried out using ensembles of unquenched gauge fields generated by the MILC Collaboration. With an improved staggered action for light quarks, we are able to simulate at light quark masses down to 1/8 of the strange mass. Consequently,(More)
The recently developed Symanzik-improved staggered-quark discretization allows unquenched lattice-QCD simulations with much smaller (and more realistic) quark masses than previously possible. To test this formalism, we compare experiment with a variety of nonperturbative calculations in QCD drawn from a restricted set of "gold-plated" quantities. We find(More)
A lattice QCD calculation of the B̄ → Dlν̄ decay form factors is presented. We obtain the value of the form factor h+(w) at the zero-recoil limit w = 1 with high precision by considering a ratio of correlation functions in which the bulk of the uncertainties cancels. The other form factor h−(w) is calculated, for small recoil momenta, from a similar ratio.(More)
This paper uses lattice QCD to calculate the decay constants of B and D mesons using an O(a)-improved action that takes light quark actions as a starting point, tuned so that it can be directly applied at the physical masses of the b and c quarks. The B meson decay constant f B is of particular phenomenological interest, since it is responsible for most of(More)
of a continuum field theory. The Lj are higherdimensional operators. The lattice action is adjusted so that the short-distance Kj coefficients vanish, at least approximately. The Fermilab formalism [4] takes Wilson fermions [2] with the clover action [3] and introduces different couplings for space-like and time-like interactions. Ref. [4] considers(More)