We provide results for the full set of form factors describing semileptonic Bmeson transitions to pseudoscalar mesons π, K,D and vector mesons ρ, K * ,D * . Our results are obtained within the framework of QCD Light-Cone Sum Rules with B-meson distribution amplitudes. We recalculate and confirm the results for the leading-twist twoparticle contributions in the literature. Furthermore, we calculate and provide new expressions for the two-particle contributions up to twist four. Following new developments for the three-particle distribution amplitudes, we calculate and provide new results for the complete set of three-particle contributions up to twist four. The form factors are computed numerically at several phase space points using up-to-date input parameters, including correlations across phase space points and form factors. We use a model ansatz for all contributing B-meson distribution amplitudes that is self-consistent up to twistfour accuracy. We find that the higher-twist two-particle contributions have a substantial impact on the results, and dominate over the three-particle contributions. Our numerical results, including correlations, are provided as machine-readable ancillary files. We discuss the qualitative phenomenological impact of our results on the present b anomalies.

We revisit the theoretical predictions and the parametrization of non-local matrix elements in rare $$ {\overline{B}}_{(s)}\to \left\{{\overline{K}}^{\left(\ast \right)},\phi \right\}{\mathrm{\ell}}^{+}{\mathrm{\ell}}^{-} $$ B ¯ s → K ¯ ∗ ϕ ℓ + ℓ − and $$ {\overline{B}}_{(s)}\to \left\{{\overline{K}}^{\ast },\phi \right\}\gamma $$ B ¯ s → K ¯ ∗ ϕ γ decays. We improve upon the current state of these matrix elements in two ways. First, we recalculate the hadronic matrix elements needed at subleading power in the light-cone OPE using B-meson light-cone sum rules. Our analytical results supersede those in the literature. We discuss the origin of our improvements and provide numerical results for the processes under consideration. Second, we derive the first dispersive bound on the non-local matrix elements. It provides a parametric handle on the truncation error in extrapolations of the matrix elements to large timelike momentum transfer using the z expansion. We illustrate the power of the dispersive bound at the hand of a simple phenomenological application. As a side result of our work, we also provide numerical results for the Bs → ϕ form factors from B-meson light-cone sum rules.

We carry out a comprehensive analysis of the full set ofBq → D ( * ) q form factors for spectator quarks q = u, d, s within the framework of the Heavy-Quark Expansion (HQE) to order O αs, 1/m b , 1/m 2 c . In addition to the available lattice QCD calculations we make use of two new sets of theoretical constraints: we produce for the first time numerical predictions for the full set ofBs → D ( * ) s form factors using Light-Cone Sum Rules with Bs-meson distribution amplitudes. Furthermore, we reassess the QCD three-point sum rule results for the Isgur-Wise functions entering all our form factors for both q = u, d and q = s spectator quarks. These additional constraints allow us to go beyond the commonly used assumption of SU (3)F symmetry for theBs → D ( * ) s form factors, especially in the unitarity constraints which we impose throughout our analysis. We find the coefficients of the IW functions emerging at O 1/m 2 c to be consistent with the naive O (1) expectation, indicating a good convergence of the HQE. While we do not find significant SU (3) breaking, the explicit treatment of q = s as compared to a simple symmetry assumption renders the unitarity constraints more effective. We find that the (pseudo)scalar bounds are saturated to a large degree, which affects our theory predictions. We analyze the phenomenological consequences of our improved form factors by extracting |V cb | fromB → D ( * ) ν decays and producing theoretical predictions for the lepton-flavour universality ratios R(D), R(D * ), R(Ds) and R(D * s ), as well as the τ -and D * q polarization fractions for theBq → D ( * ) q τ ν modes.

We provide updated predictions for the hadronic decays $$\bar{B}_s^0\rightarrow D_s^{(*)+} \pi ^-$$ B ¯ s 0 → D s ( ∗ ) + π - and $$\bar{B}^0\rightarrow D^{(*)+} K^-$$ B ¯ 0 → D ( ∗ ) + K - . They are based on $${\mathcal {O}}(\alpha _s^2)$$ O ( α s 2 ) results for the QCD factorization amplitudes at leading power and on recent results for the $$\bar{B}_{(s)} \rightarrow D_{(s)}^{(*)}$$ B ¯ ( s ) → D ( s ) ( ∗ ) form factors up to order $$\mathcal{O}(\Lambda _\mathrm{QCD}^2/m_c^2)$$ O ( Λ QCD 2 / m c 2 ) in the heavy-quark expansion. We give quantitative estimates of the matrix elements entering the hadronic decay amplitudes at order $$\mathcal{O}(\Lambda _\mathrm{QCD}/m_b)$$ O ( Λ QCD / m b ) for the first time. Our results are very precise, and uncover a substantial discrepancy between the theory predictions and the experimental measurements. We explore two possibilities for this discrepancy: non-factorizable contributions larger than predicted by the QCD factorization power counting, and contributions beyond the Standard Model. We determine the $$f_s/f_d$$ f s / f d fragmentation fraction for the CDF, D0 and LHCb experiments for both scenarios.

We provide improved Standard Model theory predictions for the exclusive rare semimuonic processes B → K(*)μ+μ− and Bs → ϕμ+μ−. Our results are based on a novel parametrization of the non-local form factors, which manifestly respects a recently developed dispersive bound. We critically compare our predictions to those obtained in the framework of QCD factorization. Our predictions provide, for the first time, parametric estimates of the systematic uncertainties due to non-local contributions. Comparing our predictions within the Standard Model to available experimental data, we find a large tension for B → Kμ+μ−. A simple model-independent analysis of potential effects beyond the Standard Model yields results compatible with other approaches, albeit with larger uncertainties for the B → K*μ+μ− and Bs → ϕμ+μ− decays. Our approach yields systematically improvable predictions, and we look forward to its application in further analyses beyond the Standard Model.

We analyze in detail the angular distributions in $${\bar{B}}\rightarrow D^*\ell {{\bar{\nu }}}$$ B ¯ → D ∗ ℓ ν ¯ decays, with a focus on lepton-flavour non-universality. We investigate the minimal number of angular observables that fully describes current and upcoming datasets, and explore their sensitivity to physics beyond the Standard Model (BSM) in the most general weak effective theory. We apply our findings to the current datasets, extract the non-redundant set of angular observables from the data, and compare to precise SM predictions that include lepton-flavour universality violating mass effects. Our analysis shows that the number of independent angular observables that can be inferred from current experimental data is limited to only four. These are insufficient to extract the full set of relevant BSM parameters. We uncover a $$\sim 4\sigma $$ ∼ 4 σ tension between data and predictions that is hidden in the redundant presentation of the Belle 2018 data on $${\bar{B}}\rightarrow D^*\ell {{\bar{\nu }}}$$ B ¯ → D ∗ ℓ ν ¯ decays. This tension specifically involves observables that probe $$e-\mu $$ e - μ lepton-flavour universality. However, we find inconsistencies in these data, which renders results based on it suspicious. Nevertheless, we discuss which generic BSM scenarios could explain the tension, in the case that the inconsistencies do not affect the data materially. Our findings highlight that $$e-\mu $$ e - μ non-universality in the SM, introduced by the finite muon mass, is already significant in a subset of angular observables with respect to the experimental precision.

is an open-source software for a variety of computational tasks in flavor physics. Its use cases include theory predictions within and beyond the Standard Model of particle physics, Bayesian inference of theory parameters from experimental and theoretical likelihoods, and simulation of pseudo events for a number of signal processes. ensures high-performance computations through a back-end and ease of usability through a front-end. To achieve this flexibility, enables the user to select from a variety of implementations of the relevant decay processes and hadronic matrix elements at run time. In this article, we describe the general structure of the software framework and provide basic examples. Further details and in-depth interactive examples are provided as part of the online documentation.

We perform the first calculation of form factors in the semileptonic decays B → D1(2420)ℓνℓ and B → $$ {D}_1^{\prime } $$ D 1 ′ (2430)ℓνℓ using QCD light-cone sum rules (LCSRs) with B-meson distribution amplitudes. In this calculation the c-quark mass is finite. Analytical expressions for two-particle contributions up to twist four are obtained. To disentangle the D1 and $$ {D}_1^{\prime } $$ D 1 ′ contributions in the LCSRs, we suggest a novel approach that introduces a combination of two interpolating currents for these charmed mesons. To fix all the parameters in the LCSRs, we use the two-point QCD sum rules for the decay constants of D1 and $$ {D}_1^{\prime } $$ D 1 ′ mesons augmented by a single experimental input, that is the B → D1(2420)ℓνℓ decay width. We provide numerical results for all B → D1 and B → $$ {D}_1^{\prime } $$ D 1 ′ form factors. As a byproduct, we also obtain the D1- and $$ {D}_1^{\prime } $$ D 1 ′ -meson decay constants and predict the lepton-flavour universality ratios R(D1) and R($$ {D}_1^{\prime } $$ D 1 ′ ).