Related papers: R(s) and hadronic tau-Decays in Order alpha_s^4: t…
We present a brief (mainly bibliographical) report on recently performed calculations of terms of order O(\alpha_s^4 n_f^2) and O(\alpha_s^4 n_f^2 m_q^2) for hadronic Z and \tau decay rates. A few details about the analytical evaluation of…
The total tau hadronic width can be accurately calculated using analyticity and the operator product expansion. The result turns out to be very sensitive to the value of alpha_s(m_tau^2), providing a precise determination of the strong…
The total $\tau$ hadronic width can be accurately calculated using analyticity and the operator product expansion. The theoretical analysis of this observable is updated to include all available perturbative and non-perturbative…
With the help of a physically motivated ansatz, which is fitted to the data, we estimate the size of possible duality violations in hadronic tau decay. The result is that the uncertainty associated with these violations could impact the…
Some important aspects of hadronic tau decays are reviewed: the determination of alpha_s from the inclusive tau hadronic width, the measurement of |V_{us}| through the Cabibbo-suppressed decays of the tau, and the theoretical description of…
Analytic formulae for the one-loop order QCD corrections to the differential width of the semileptonic b decay are given with the tau polarization taken into account. Thence the polarization of tau is expressed by its energy and the…
The first complete calculation of the quadratic quark mass correction to the correlator of the two currents relevant for the strangeness-changing semihadronic tau-decay rate is presented including its real part at the four-loop level. This…
The two highest precision determinations of alpha_s(M_Z^2), that based on the analysis of short-distance-sensitive lattice observables, and that based on an analysis of hadronic tau decay data, have, until very recently, given results which…
An updated measurement of alpha_s(m_tau) from ALEPH tau hadronic spectral functions is presented. We report a study of the perturbative prediction(s) showing that the fixed-order perturbation theory manifests convergence or principle…
The total $\tau$ hadronic width can be accurately calculated using analyticity and the operator product expansion. The theoretical analysis of this observable is updated to include all available perturbative and non-perturbative…
The results of evaluation of mixed QED X QCD corrections to R(s) in e^+e^- annihilation and R_{\tau} in hadronic decay of the \tau lepton to O(\alpha^n\alpha_s^m), m+n \leq 3, are presented. The net effect on \alpha_s(M_Z) from the Z decay…
We present an update of the measurement of alpha_s(m_tau) from ALEPH tau hadronic spectral functions. We report a study of the perturbative prediction(s) showing that the fixed-order perturbation theory manifests convergence problems not…
The QCD analysis of hadronic tau decays is reviewed and a summary of the present phenomenological status is presented. The following topics are discussed: the determination of alpha_s(m_tau) = 0.338 +- 0.012 from the inclusive tau hadronic…
We revisit the determination of alpha_s(m_tau) using a fit to inclusive tau hadronic spectral moments in light of (1) the recent calculation of the fourth-order perturbative coefficient K_4 in the expansion of the Adler function, (2) new…
This paper presents $\alpha_s$ corrections to the inclusive semitauonic $B \to X_c \tau \bar{\nu}_\tau$ decay width and leptonic invariant mass spectrum up to order $1/m_b^3$ in the heavy quark expansion. Analytical results with full…
Recently computed terms of orders O(\alpha_s^4 n_f^2) in the perturbative series for the tau decay rate, and similar (new) strange quark mass corrections, are used to discuss the validity of various optimization schemes. The results are…
Analytic formulae are given for order alpha_s perturbative QCD corrections to the double differential distribution of the tau lepton energy and the invariant mass of the tau + antineutrino system in semileptonic decays of the bottom quark.…
We calculate the $\alpha_s$ corrections to the form factors which parameterize the hadronic tensor relevant for inclusive semileptonic $B \rightarrow X \tau\bar\nu_{\tau}$ and $\Lambda_b \rightarrow X \tau\bar\nu_{\tau}$ decays. We apply…
In this note radiative corrections to the total hadronic decay rate of the $\tau$-lepton are studied employing perturbative QCD and the operator product expansion. We calculate quadratic quark mass corrections to the decay rate ration…
Hadronic tau decays offer the possibility of determining the strong coupling alpha_s at relatively low energy. Precisely for this reason, however, good control over the perturbative QCD corrections, the non-perturbative condensate…