Related papers: $B \to D^{**}$ -- puzzle 1/2 vs 3/2
I present analyses of semileptonic $B_c$ decays. I first discuss the decays induced by $c \to \{s, d \}$ transitions, in particular $B_c \to B_a \, \bar{\ell} \, \nu_\ell$ and $B_c \to B_a^*(\to B_a \, \gamma) \, \bar{\ell} \, \nu_\ell$…
A combination of continuum and lattice methods is used to investigate systematic issues in the finite-energy-sum-rule determination of $V_{us}$ based on flavor-breaking combinations of hadronic $\tau$ decay data. Results for $V_{us}$…
In recent times, one of the strongest hints of Physics Beyond the Standard Model (BSM) has been the anomaly in the ratios $R_D$ and $R_{D^\ast}$ measured in the charged current decays of $B$-mesons. In this work, we perform a comprehensive…
Non-leptonic $B^0_s \rightarrow D_s^{\pm} K^{\mp}$ transitions are particularly interesting processes to test the Standard Model. As these decays occur via pure tree diagrams, they allow a theoretically clean determination of the angle…
Semileptonic $b \to c$ transitions, and in particular the ratios $R(D^{(*)}) = \frac{\Gamma(B \rightarrow D^{(*)} \tau \nu )}{\Gamma(B \rightarrow D^{(*)} \ell \nu )}$, can be used to test the universality of the weak interactions. In light…
We present a summary of the latest measurements of branching fractions and direct CP violations in the charmless hadronic two-body B decays B -> K^+ pi^-, K^+ pi^0, K^0 pi^+ and K^0 pi^0, performed by the Belle, BABAR, CDF and CLEO…
We propose a method to non-perturbatively calculate the forward-scattering matrix elements relevant to inclusive semi-leptonic B meson decays. Corresponding hadronic structure functions at unphysical kinematics are accessible through…
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…
This paper reviews semileptonic decays of $B$-mesons to states containing charm mesons, i.e., D, D*, D** and possible non-resonant D^{(*)}npi states as well. The paper covers measurement of branching fractions, form-factors and, most…
The final-state phases in $\bar{B} \to D \pi, D^* \pi$, and $D \rho$ decays appear to follow a pattern similar to those in $D \to \bar{K} \pi$, $\bar{K}^* \pi$, and $\bar{K} \rho$ decays. Each set of processes is characterized by three…
The present status of lattice calculations of $f_D$, $f_B$ and some mass splittings are discussed. When one includes the uncertainties due to discretization errors, the results do not yet have a sufficient precision to be relevant to…
We study semileptonic sum rules for $b \to c \tau \overline{\nu}$ transitions involving orbitally excited charm hadrons. Starting from the amplitude-level relation implied by the heavy quark symmetry, we construct sum rules relating these…
Dispersive constraints on the shape of the form factors which describe the exclusive decays B -> D^(*) l nu are derived by fully exploiting spin symmetry in the ground-state doublet of heavy-light mesons. The analysis includes all twenty…
We propose determining |V_{ub}| from inclusive semileptonic B decay using combined cuts on the leptonic and hadronic invariant masses to eliminate the b->c background. Compared to a pure dilepton invariant mass cut, the uncertainty from…
In this paper, we propose a general approach for describing hadronic B decays. Using this method, all amplitudes for such decays can be expressed in terms of contractions, though the matrix elements are not evaluated. Many years ago, Buras…
We present a very high statistics study of D and D_s semileptonic decay form factors on the lattice. We work with MILC N_f=2+1 lattices and use the Highly Improved Staggered Quark action (HISQ) for both the charm and the strange and light…
The $R(D^{(*)})$ puzzle stands for a $\sim3\sigma$ violation of lepton flavor universality between the decay rates of $B\to D^{(*)}\tau\nu$ and $B\to D^{(*)}\ell\nu$, where $\ell=e,\mu$. If it is accounted for by new physics, there is no…
In this letter we discuss the masses and the splittings of 1(2S+1)P_J states in the spectrum of D and B mesons, as they appear in the approach of the QCD string with quarks at the ends. We find good agreement of our predictions with those…
Discrepancies between Standard Model predictions and experimental measurements of the fractions R_c and R_b of hadronic Z decays to charm and bottom are investigated. We show that there exists a discrepancy in two complementary…
We present an updated determination of the values of $\vert V_{cb} \vert$, $R(D^*)$ and $\vert V_{ub} \vert/\vert V_{cb} \vert$ based on the new data on semileptonic $B \to D^* \ell \nu_\ell$ decays by the Belle and Belle-II Collaborations…