Related papers: $B \to D^{**}$ -- puzzle 1/2 vs 3/2
Semileptonic and purely leptonic decays of B meson to $\tau$, such as $B\to D^{(\ast)}\tau\nu_{\tau}$ and $B\to\tau\nu_\tau$ are studied. Recognizing that there already were some weak hints of possible deviations from the SM in the…
The significant divergence between the SM predictions and experimental measurements for the ratios, $R_{D^{(*)}}\equiv \mathcal{B}(\bar{B}\to D^{(*)}\tau^- \bar{\nu}_\tau)/ \mathcal{B}(\bar{B}\to D^{(*)} \ell^{\prime-}…
We give results for the $B$ and the $D$ meson spectrum using NRQCD on the lattice in the quenched approximation. The masses of radially and orbitally excited states are calculated as well as $S$-wave hyperfine and $P$-wave fine structure.…
The increasing accuracy of experimental results for the exclusive, semileptonic decay B -> pi l nu requires a similarly accurate calculation of the hadronic matrix elements, to determine |Vub|. We present preliminary results for the form…
Lattice calculation of $B\to D^{(*)}\ell\bar\nu$ decay form factors is now available from multiple lattice collaborations for both zero-recoil limit and non-zero recoil kinematics. Yet, there are a number of challenges we face to better…
We perform a two-flavor dynamical lattice computation of the Isgur-Wise functions tau_{1/2} and tau_{3/2} at zero recoil in the static limit. We find tau_{1/2}(1) = 0.297(26) and tau_{3/2}(1) = 0.528(23) fulfilling Uraltsev's sum rule by…
In this paper, we studied the semileptonic decays $B \to D^{(*)} l^- \bar{\nu}_l$ by using the "pQCD+Lattice QCD" method. We made the extrapolation for the six relevant form factors by using the input values obtained from the pQCD…
Anomalies in semi-leptonic $B$ decays could indicate new physics beyond the standard model(SM). There is an older puzzle in non-leptonic $B \to \pi K$ decays. The new particles, leptoquarks and diquarks, required to solve the semi-leptonic…
I present two recent pieces of work on semileptonic $B \to \pi, \rho$ decays where it is shown how lattice QCD calculations can be used to test heavy-quark symmetry and determine phenomenologically relevant quantities despite the limits on…
The $b \to c$ semileptonic sum rules provide relations between the decay rates of $B \to D^{(*)} \tau\bar\nu$ and $\Lambda_b \to \Lambda_c \tau\bar\nu$. Starting from the heavy quark and zero-recoil limits, we revisit the derivation of the…
I review the status of lattice simulations relevant for phenomenological studies of B-physics. Results for much-studied quantities such as f_B, B_B and form-factors for semileptonic decays are presented as well as those for quantities which…
Utilizing the approach recently proposed for the inclusive semi-leptonic decay rate on the lattice, we compute the differential decay rate of a $B_s$ meson for various kinematical channels. The results are compared with the contributions…
After improving the knowledge about residua of the semileptonic form factor at its first two poles we show that $f_+^{D\pi}(q^2)$ is not saturated when compared with the experimental data. To fill the difference we approximate the rest of…
It is experimentally observed that ratios of branching fractions for semitauonic and semileptonic $B$ decays, known as the $R(D^{(*)})$, are higher than Standard Model (SM) predictions. The $B \to \bar{D}^{(*)} \tau^{+} \nu_{\tau}$ decays,…
We calculate the form factors for the $B \to D^*\ell\nu_\ell$ decay in 2+1 flavor lattice QCD. For all quark flavors, we employ the M\"obius domain-wall action, which preserves chiral symmetry to a good precision. Our gauge ensembles are…
B physics has played a prominent role in investigations of new physics effects at low-energies. Presently, the largest discrepancy between a standard model prediction and experimental measurements appears in the branching ratio of the…
We analyze the inclusive semileptonic $B \to X_c \ell\nu$ structure functions in 2+1-flavor lattice QCD. The M\"obius domain-wall fermion action is used for light, strange, charm and bottom quarks. The structure function receives…
Lattice matrix elements are briefly reviewed. In the quenched approximation $f_B$, $B_B$ and $B_K$ are now under good control. Experimental hints for $f^{\rm expt}_{D_S}> f^{\rm QQCD}_{D_S}$ are noted; precise determination of $f_{D_S}$…
We stress that, although the $D^*$ is very narrow (one hundred of keV), the difference between the full $D^*$ contribution to $B \to \bar{D} \pi \pi$ and its zero width limit, which stems from the resonance tail, is surprisingly large~:…
We discuss the impact of the recent untagged analysis of ${B}^0\rightarrow D^{*}l\bar{\nu}_l$ decays by the Belle Collaboration on the extraction of the CKM element $|V_{cb}|$ and provide updated SM predictions for the $b\to c\tau\nu$…