Related papers: Determination of B*B pi coupling in unquenched QCD
A method to extract B-physics parameters (b-quark mass and fB, fBs decay constants) from currently available lattice data is presented and tested. The approach is based on the idea of constructing appropriate ratios of heavy-light meson…
The chiral Lagrangian describing the low-energy behavior of N_f=2+1+1 twisted mass lattice QCD is constructed through O(a^2). In contrast to existing results the effects of a heavy charm quark are consistently removed, leaving behind a…
We study a chiral quark model of $\pi$, $\sigma$, $\rho$, and $a_1$ mesons in the large-$N_c$ limit. We show that the quadratic $a_1-\pi$ mixing can be set to zero at zero momentum, thus protecting the $g_{\sigma\pi\pi}$ and…
It has been argued recently that the inclusion of the chiral logarithms in extrapolation of the lattice data can shift the value of the hadronic parameter xi = (fBs sqrt(B_{Bs}))/(fBd sqrt(B_{Bd})), from 1.16(6) to 1.32(10) and even higher.…
It is commonly believed that a careful investigation of the subleading terms is crucial for a better understanding of the $QCD$ factorization in charmless B decays. In this work the penguin-dominated $B\to K\pi$ decays are discussed…
We study the current estimates of $B_c\to B_s \pi$ to extract the fragmentation fraction $f_c/f_s$ at the LHCb. A rather robust estimate of $Br(B_c\to B_s \pi)$ based on factorization and lattice results for the form factor gives $f_c/f_s…
We present updated results for kaon B-parameters for operators arising in models of new physics. We use HYP-smeared staggered quarks on the $N_f = 2+1$ MILC asqtad lattices. During the last year we have added new ensembles, which has…
The form factors for the $B-->\pi$ transition are evaluated in the entire momentum transfer range by using the constraints obtained in the framework combining the heavy quark expansion and chiral symmetry for light quarks and the quark…
We determine the masses and decay constants of the pseudoscalar mesons Bs and Bc, and also the masses of the vector mesons Bs^* and Bc^*, in quenched lattice QCD with exact chiral symmetry. For 100 gauge configurations generated with…
We present a systematic analysis of the $B^{(*)}\to\pi\,\ell\,\nu$ weak decay form factors to order $1/m_b$ in the heavy quark effective theory, including a discussion of renormalization group effects. These processes are described by a set…
We describe a recently developed heavy-light chiral quark model and show how it can be used to calculate decay amplitudes for heavy mesons. In particular, we discuss B- antiB mixing, B -> D antiD, B -> D eta' and the beta term for D* -> D…
Last year we proposed using staggered fermions as the light quarks, combined with nonrelativistic heavy quarks, in simulations of heavy-light mesons. A first round of tests which focuses on the B_s meson has been completed using quenched…
We present a calculation of the B -> pi l nu form factors with domain-wall light quarks and relativistic b-quarks on the lattice. We work with the 2+1 flavor domain-wall fermion and Iwasaki gauge-field ensembles generated by the RBC and…
We study the exclusive semileptonic $B$-meson decays $B\to K(\pi)\ell^+\ell^-$, $B\to K(\pi)\nu\bar\nu$, and $B\to\pi\tau\nu$, computing observables in the Standard model using the recent lattice-QCD results for the underlying form factors…
A novel method to calculate f_B on the lattice is introduced, based on the study of the dependence of finite size effects upon the heavy quark mass of flavoured mesons and on a non-perturbative recursive finite size technique. We avoid the…
We present a lattice QCD calculation of the heavy-light decay constants f_B and f_Bs performed with Nf=2 maximally twisted Wilson fermions, at four values of the lattice spacing. The decay constants have been also computed in the static…
Rare $b\to s\ell^+\ell^-$ decays provide some of the most sensitive tests of the Standard Model and require precise and systematically improvable hadronic input from lattice QCD. For the phenomenologically important channel $B\to…
The $B_{l4}$ decays offer an independent method for determining the Cabibbo-Kobayashi-Maskawa matrix element $\vert V_{ub} \vert$, with a QCD analysis of the underlying $B \to \pi\pi$ form factors serving as a crucial component. We present…
I consider the recent proposal by R. Frezzotti and G. Rossi to chirally improve Wilson fermions in such a way that mixings among operators of different chirality can be excluded. The method, which is based on the use of twisted mass QCD…
We present a preliminary calculation of B_K using domain-wall valence quarks and 2+1 flavors of improved staggered sea quarks. Both the size of the residual quark mass, which measures the amount of chiral symmetry breaking, and of the mixed…