Related papers: A Mixed Tau-Electroproduction Sum Rule for V_us
This talk reviews the recent progress in the extraction of bound-state characteristics from the operator-product expansion (OPE) for field-theory correlators, which constitutes the basis of the method of QCD sum rules. This progress is…
We fit the available data on exclusive semileptonic $b\to u\ell^-\bar\nu$ decays within the Standard Model and in the Weak Effective Theory. Assuming Standard Model dynamics, we find $|V_{ub}| = 3.59^{+0.13}_{-0.12} \times 10^{-3}$. Lifting…
I extract the strange-quark mass using a $\tau$-like decay sum rule for the $\phi$-meson, and some other sum rules involving its difference with the vector component of the hadronic $\tau$-decay. As a conservative estimate, one obtains to…
Applications of QCD sum rules to exclusive decays of heavy mesons are reviewed. In detail, we discuss the calculations of the B and $D$ decay constants, the heavy-to-light form factors $f^+(p^2)$ and $f^0(p^2)$, and the strong couplings…
We have derived constraints on the tau neutrino mass and fourth generation mixing from an analysis of the partial widths of tau lepton decays, in particular: tau -> e nu nu_tau, tau -> mu nu nu_tau, tau -> pi nu_tau, tau -> K nu_tau. We…
Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged…
Recent experimental data on tau decays are used to reconstruct the difference in hadronic spectral densities with vector and axial-vector quantum numbers. The saturation of Das-Mathur-Okubo and Weinberg sum rules is studied. Two methods of…
QCD finite energy sum rules, together with the latest updated ALEPH data on hadronic decays of the tau-lepton are used in order to determine the vacuum condensates of dimension $d=2$ and $d=4$. These data are also used to check the validity…
The ALEPH data on hadronic tau-decay is throughly analysed in the framework of QCD. The perturbative calculations are performed in 1-4-loop approximation. The analytical properties of the polarization operators are used in the whole complex…
We revisit, scrutinize, improve, confirm and complete our previous results [1-3] from the scalar di-gluonium sum rules within the standard SVZ-expansion at N2LO without instantons and beyond the minimal duality ansatz : "one resonance + QCD…
Narison's $\tau$-decay-like sum rule for determining the strange quark mass is re-investigated, taking into account isospin-breaking corrections in the extraction of the input spectral functions from $e^+e^-\to hadrons$ data. The…
Hadronic tau decays provide several ways to extract the Cabbibo-Kobashi-Maskawa (CKM) matrix element V_{us}. The most precise determination involves using inclusive tau decays and requires as input the total branching ratio into strange…
The divergent large-order behaviour of the perturbative series relevant for the determination of $\as$ from $\tau$ decay is controlled by the leading ultraviolet (UV) renormalon. Even in the absence of the first infrared (IR) renormalon, an…
An exhaustive number of QCD finite energy sum rules for $\tau$-decay together with the latest updated ALEPH data is used to test the assumption of global duality. Typical checks are the absence of the dimension $d=2$ condensate, the…
In production processes, e.g. J/Psi -> omega-pi-pi or pbar-p -> 3pi, the sigma and fo(980) overlap in the same partial wave. The conjecture of Extended Unitarity (EU) states that the pi-pi pair should have the same phase variation as pi-pi…
Using the most recent release of the ALEPH $\tau$ decay data, we present a very detailed phenomenological update of the $\alpha_s(m_\tau^2)$ determination. We have exploited the sensitivity to the strong coupling in many different ways,…
We update the |V$_{us}$| determinations using the HFLAV 2018 report tau branching fraction results with recent new estimates of the $\pi\ell2$ and $K\ell2$ radiative corrections. There are minor changes of the central values and…
We present a QCD sum rule calculation of the Isgur-Wise form-factor tau_1(v.v') and tau_2(v.v') for the semileptonic decays B->D_1(2420)l\bar\nu and B->D_2^*(2460)l\bar\nu in the framework of heavy quark effective theory. These two…
A varying external field approach in QCD sum rules is formulated in a systematic way to treat the weak decay form factors and their $q^2$ dependence in the process of $B \to \rho \ell \bar\nu_\ell$. From the form factor sum rules, we can…
We present a sum-rule extraction of the decay constants of heavy-light mesons from the two-point correlator of pseudoscalar currents. To this end, we compare the perturbative expansions for the correlator and the decay constant performed in…