In this talk I will present the most updated status of the global fits to all b->sll data. An anatomy of the main observables involved will be discussed together with their theoretical aspects. The most relevant scenarios of New Physics will be presented showing the degeneracy we observe systematically in all these years. I will present a full understanding of the reason of this degeneracy of...
Exclusive semileptonic $B_{(s)}$ decays are theoretically described by scalar and vector form factors. Combining experimental branching fraction measurements with theoretical form factor predictions, the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$ can be extracted. In addition $R$-ratios testing lepton flavor universality can be derived to directly compare standard model predictions to...
I will introduce two novel mechanisms to produce pairs of leptoquarks at Large Hadron Collider and present several case studies to discuss the associated phenomenological implications.
We present HPQCD's improved scalar, vector and tensor form factors for $B \to K$ decay using the Highly Improved Staggered Quark formalism for more accurate normalisation of the weak currents and working on very fine lattices to cover the full physical $q^2$ range. Our uncertainties at $q^2=0$ are a factor of three better than earlier work.
We compare Standard Model observables using our...
The recently developed $B$-mesogenesis scenario predicts the decays of $B$ mesons into a baryon and a hypothetical dark antibaryon in the final state. In this work, we suggest to apply QCD light-cone sum rules to estimate the partial width of the simplest exclusive decay mode $B^+\to p \Psi$, where $\Psi$ is a dark antibaryon. We consider two sample models of $B$-mesogenesis and identify the...
The rate of semitauonic B decays has been consistently above theory expectations since these decays were first measured. Recently significant differences between the forward-backward asymmetry in B -> Denu and B -> Dmunu were also reported. Belle II data are well suited to probe these anomalies. The low-background collision environment along with the possibility of partially or fully...
We present analytical results for higher order corrections to the decay spectrum of inclusive semileptonic heavy hadron weak decays using the heavy quark expansion (HQE). We describe the analytical computation of the spectrum of the leptonic invariant mass for $B \rightarrow X_c \ell \bar{\nu}$ up to terms of order $1/m_b^3$ within the HQE at next-to-leading order (NLO) in $\alpha_s$. The full...
I will describe the first results of a new method to compute inclusive semileptonic decays on the lattice and the future perspectives.
QCD light-cone sum rules (LCSRs) are a method to calculate the relevant hadronic matrix elements in exclusive $b$-quark decays. I focus on the LCSRs with $B$ or $\Lambda_b$ distribution amplitudes. The versatility of this method allows to apply it to a wide variety of decays, especially to those where lattice QCD calculations are not available yet.
In this spirit, I present a first...
The CKM matrix element $V_{ub}$ is both the smallest and least known of all CKM matrix elements; its current value has been determined in many ways, but directly primarily through the exclusive process $B\to\pi\ell\nu$. In this talk, we will present our progress towards a lattice QCD determination of the $V_{ub}$ matrix element from a novel transition - $B\to \rho \ell \nu$. On this ensemble,...
We discuss the Lorentz decomposition of $B \to \gamma^*$ matrix elements in terms of hadronic form factors, which are needed for a theory description of $B^- \to \ell^- \bar{\nu}_\ell \ell' \bar{\ell'}$ decays.
Our approach closely follows the Bardeen–Tung–Tarach procedure and ensures freedom from kinematic singularities, which is needed to apply dispersion relations in the photon momentum....
Lattice QCD computations of a number of physical quantities, including leptonic decay rates, yield sufficiently precise results that electromagnetic corrections need to be implemented to make further progress in determining the parameters of the Standard Model and checking consistency with the corresponding experimental results. After a brief introduction to the framework, I will present the...
In this talk I will report on the calculation of NNLO QCD corrections to the
flavor observables in the mixing of neutral $B$ mesons and discuss their
numerical impact. The physical relevance of this work stems from the fact
that experimental measurements of e.g. the flavor mixing parameter
$\Delta \Gamma_{12}^s$ have already achieved per cent level accuracy,
while theoretical predictions...
Motivated by recent indications that the rates of colour-allowed non-leptonic channels are in tension with their Standard Model predictions based on QCD factorisation, we investigate the potential to study CP asymmetries with these decays. In the Standard Model, these flavour-specific decays are sensitive to CP violation in $B^0_{(s)}$--$\bar{B}^0_{(s)}$ mixing, which is predicted with low...
I will present a comprehensive analysis of inclusive decay widths of charmed mesons within the framework of the HQE. The theoretical predictions for D-mesons lifetimes and their ratios are found to be in agreement with the current experimental data, albeit with very large uncertainties. Open questions and potential theoretical improvements will also be discussed.
I present updated predictions for inclusive charmed hadron lifetimes, focusing particularly on the baryons. These predictions are compatible with recent LHCb measurements, which measured the lifetime of $\Omega_c^0$ to be four times greater than earlier results. I will also discuss areas for potential improvement of the predictions, which will be much-needed in order to compete with...
The Standard Model decay rate of the $B_c$ meson is discussed together with a novel approach based on the usage of experimental data in combination with an operator product expansion. In the new method differences of $B$, $D$ and $B_c$ meson widths are considered, for which the free-quark contributions drop out, possibly leading to a reduction of the uncertainty of the theoretical prediction.
I discuss the recently finished calculation of the next-to-next-to-leading order corrections to the CP asymmetry in flavour-specific $B_{d,s}$ decays and the phenomenological studies
which will be possible with better data.
We address the non-perturbative calculation of the decay rate of the inclusive semi-leptonic B(s) mesons decay from lattice QCD. Precise theoretical Standard Model predictions are key ingredients in searches for new physics. This type of computation may eventually provide new insight into the long-standing tension between the inclusive and exclusive determination of the $V_{cb}$ and $V_{ub}$...
We present the status of ongoing work to extract pseudoscalar and vector decay constants for $B^{(*)}$, $B_s^{(*)}$ and $B_c^{(*)}$ mesons and determine phenomenologically interesting ratios such as $f_{B_s}/f_B$ or $f_{B^*}/f_B$. Our results extrapolated to physical quark masses and the continuum are compared to predictions by other lattice collaborations and QCD sum rules, and are used to...
The combination of the experimentally measurable mass differences between the flavour eigenstates of neutral mesons and theoretical predictions of the corresponding hadronic matrix elements provide direct access to the CKM matrix elements $V_{td}$ and $V_{ts}$. Furthermore, the full dimension-6 operator basis provides valuable constraints for New Physics models. I will present the status of...
In this talk we present a new method to measure the ratio of the top-quark branching fractions, which expands upon a previous CMS analysis. We incorporate an additional orthogonal light-quark-tagger and extend the statistical model implemented by the CMS collaboration to include the number of quark-tagged jets. We show that the interplay between these different orthogonal jet-taggers increases...
