B → ρlν form factors in lattice QCD

ρlν form factors in lattice QCD

Semileptonic Decays and Ckm Matrix Elements in a Tcf

We argue that a Tau-Charm factory (TCF) could improve our knowledge of CKM matrix elements since it is an incomparable tool to check the models and methods applied to extract Vbu from B decay partial widths. We report on some recent proposals to improve on parton model. Turning to exclusive decays, we compare the predictions from quark models, QCD sum rules, effective Lagrangians and lattice QC...

Theory of the Endpoint Region of Exclusive Rare B Decays

The third row of the CKM matrix is poorly determined because it involves the top quark. Of the first two rows, the Vub element is the least well known, with a precision of about 20% in its magnitude, |Vub|. The measurement of |Vub| through inclusive charmless semileptonic B decays is complicated by the large background from charmfull semileptonic B decays. Experimentally, cuts may be imposed to...

A Quark-Meson Model for Heavy Mesons: Semi-Leptonic Decays

I consider a model for heavy meson decays based on an effective quark-meson Lagrangian. The model is constrained by the known symmetries of QCD in the mQ → ∞ limit for the heavy quarks, and chiral symmetry in the light quark sector. Using a limited number of free parameters it is possible to compute several phenomenological quantities, e.g. the leptonic B and B∗∗ decay constants; the Isgur-Wise...

Form factor relations for heavy-to-light meson transitions: tests of the Quark Model predictions

In the amplitudes for the weak semi-leptonic decays of mesons, the hadronic matrix elements are parametrized by form factors that describe the non-perturbative QCD effects and are a source of large theoretical uncertainties. In the case of heavy-to-light meson transitions, a Quark Model derivation leads to very general relations between those hadronic form factors, such that only two remain tha...