We present a determination of Vcb taking into account the most recent data on exclusive decays as well as form factor calculations from lattice QCD. We employ unitarity constraints within the Boyd-Grinstein-Lebed (BGL) parametrization and carefully study their impact on the results. Furthermore, we give updated Standard Model predictions for the lepton-flavor non-universality observables R(D(*)).
We perform a fit of the Isgur-Wise function including ${\cal O}(1/m_c^2)$ corrections to the available theoretical and experimental constraints. We include the tensor form factors and the corresponding unitarity bounds for the first time in this framework. We discuss the compatibility between the different constraints. We also compare our results with those of other methods. We present our SM...
We propose a simultaneous analysis of $B \to D \ell \nu$ and $B\to D^{*} \ell \nu$ decays to measure model-independent observables for the determination of $|V_{cb}|$. The $B\to D^{*} \ell \nu$ decays is partially reconstructed, removing systematic uncertainty on $|V_{cb}|$ from the soft-pion reconstruction. By assuming equality of the semileptonic decay width of $B^0$ and $B^+$ mesons, we...
Semileptonic $B$ decays involving multiple final-state hadrons play a crucial role as backgrounds to studies of lepton flavour universality or recent anomaly observed in $B \rightarrow K\nu\nu$. Furthermore, these poorly understood decays constitute sizeable signal components in measurements of inclusive $B \rightarrow X_{u/c} \ell\nu$ decays and the subsequent extraction of inclusive...
In this talk, we present studies of two semileptonic decays with two hadrons in the final state. First, we’ll discuss $B \rightarrow D \pi \ell \nu$ decays that not only constitute a sizeable background for $R(D^{(*)})$ determinations, but also comprise a largely unknown signal component for inclusive $B \rightarrow X_{c}\ell \nu$ decays. The dominant decay chain proceeds through resonant $B...
The $R(D^{(*)})$ ratio is an excellent test of Lepton Flavor Universality, that promises to elucidate the nature of potential Beyond the Standard Model physical processes. In this talk, we present the latest $R(D^{(*)})$ measurements from the Belle II experiment. Additionally, we explore a likelihood based combination of different analyses relying on orthogonal selections, that goes beyond...
Differential measurements of semileptonic b-hadron decays not only further our understanding of hadronic effects and CKM matrix elements, but are also powerful probes for effects beyond the Standard Model description. An overview of the angular measurements currently pursued at LHCb is presented, including expected New Physics sensitivities and prospects for future measurements.
Semileptonic b-baryons decays provide powerful probes for testing the Standard Model and for searching for New Physics effects. In this contribution, the LHCb semileptonic measurements with b-baryons will be presented: the status, the analyses ongoing and the prospect for future.
Experimental results for moments of the leptonic $q^2$-spectrum in inclusive semileptonic B-meson decays often involve cuts on $q^2$. Therefore, the spectrum itself (rather than its moments only) needs to be evaluated on the theoretical side. We present results of our calculation of $\mathcal{O}(\alpha_s^2)$ corrections to this spectrum that have been obtained via a numerical solution to...
We present a new global fit for inclusive $V_{cb}$ decays based on the Kolya open-source library, utilizing the full available set of spectral moments of semileptonic $B\to X_c \ell \nu$ decays with state-of-the-art precision. Our approach includes a novel prescription to estimate the uncertainty arising from missing higher-order contributions of order $1/m_b^4$ in the heavy quark expansion...
We report on the progress in the nonperturbative calculation of the decay rate for inclusive semileptonic decays of charmed and bottomed mesons. We provide an overview on the formalism used to reconstruct the inclusive rate and address the ongoing analysis into understanding the systematic errors associated with the analysis, focusing on the error due to the approximation and finite-volume...
In the past two decades significant advances have been made
on the perturbative ingredients of the leading-power factorization
formula for $B \to X_u \ell \nu$, as well as local parameters in the
heavy-quark expansion. An update for partial rates in the
"shape-function region" is overdue. The main uncertainty still
concerns the leading-power shape function, where we explore novel
ideas...
This talk will review the inclusive B->Xu l nu measurements at Belle and present the status of ongoing activities at Belle II with a focus on the potential improvements in the analysis strategies.
The calculation of local form factors involved in the SM predictions of semileptonic
$B$-meson decays at low-$q^2$ is a crucial ingredient in the assessment of the $B$-anomalies.
We revisit their calculation in QCD Light-Cone Sum Rule with $B$-meson Light-Cone Distribution Amplitudes. In our strategy, we bypass the semi-global quark-hadron duality (QHD) approximation which usually...
The $SU(2)_L\times U(1)_Y$ invariance of the Standard Model Effective Field Theory (SMEFT) predicts multiple restrictions in the space of Wilson coefficients of $U(1)_{em}$ invariant effective lagrangians such as the Low-energy Effective Field Theory (LEFT), used for low-energy flavor-physics observables, or the Higgs Effective Field Theory (HEFT) in unitary gauge, appropriate for...
We propose novel methods to determine the $\Upsilon(4S)\to B^+B^-$ and $\Upsilon(4S)\to B^0\bar B^0$ decay rates. The precision to which they and their ratio are known yields at present a limiting uncertainty around 2% in measurements of absolute $B$ decay rates, and thus in a variety of applications, such as precision determinations of elements of the Cabibbo-Kobayashi-Maskawa matrix and...
Semileptonic measurements take a very long time. Particularly at LHCb where the datasets are large and background control is very important and fiddly. Most of these reasons are inherent to the measurements themselves but there are a few aspects which are repeated for each analysis which could be streamlined. This talk will open a broad discussion of how to streamline with a few proposals of...
