相关论文: On the longitudinal contributions to hadronic tau …
Being a determination at low energies, the analysis of hadronic tau decay data provides a rather precise determination of the strong coupling alpha_s after evolving the result to M_Z. At such a level of precision, even small…
Recent sum rule determinations of |V_us|, employing flavor-breaking combinations of hadronic tau decay data, are significantly lower than either expectations based on 3-family unitarity or determinations from K_ell3 and…
New finite energy sum rules (FESR's) for extracting m_s from hadronic tau decay data are constructed which (1) significantly reduce potential theoretical uncertainties present in existing sum rule analyses and (2) remove problems associated…
A method for analysing the hadronic resonance contributions in $\bar{B}^{0} \rightarrow \bar{K}^{*0}\mu^{+}\mu^{-}$ decays is presented. This method uses an empirical model that relies on measurements of the branching fractions and…
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…
We study extractions of |V_us| based on finite energy sum rule (FESR) analyses of hadronic tau decay data. We show (i) that the ``(0,0) spectral weight'' implementation (proposed previously in the literature as a favorable version of this…
The finite energy sum rule extraction of the strong coupling {\alpha}_s from hadronic {\tau} decay data provides one of its most precise experimental determinations. As precision improves, small non-perturbative effects become increasingly…
All ALEPH measurements of branching ratios of tau decays involving kaons are summarized including a combination of results obtained with K^0_S and K^0_L detection. The decay dynamics are studied, leading to the determination of…
Recently, we extracted the strong coupling, $\alpha_s(m_\tau^2)$, from the revised ALEPH data for non-strange hadronic tau decays. Our analysis is based on a method previously used for the determination of the strong coupling from OPAL…
We present the study of radiative tau decay ($\tau^- \rightarrow \pi^- \nu_\tau \gamma$), computing the structure dependent contribution using Light Cone Sum Rules. This decay includes the same form factors as the radiative pion decay with…
We consider the scalar form factor in $\tau \to K\pi \nu_\tau$ decays. It receives contributions both from the scalar resonance $K_0^*(1430)$ and from the scalar projection of off-shell vector resonances. We construct a model for the…
In previous work we have combined the $\pi^-\pi^0$, $2\pi^-\pi^+\pi^0$ and $\pi^-3\pi^0$ spectral data obtained from hadronic $\tau$ decays measured by the ALEPH and OPAL experiments, together with electroproduction data for several of the…
Hadronic decays of the $\tau$ lepton provide a clean environment to study hadron dynamics in an energy regime dominated by resonances, with the interesting information captured in the spectral functions. Recent results from ALEPH on…
Recent experimental data for the differential decay distribution of the decay $\tau^-\to\nu_\tau K_S\pi^-$ by the Belle collaboration are described by a theoretical model which is composed of the contributing vector and scalar form factors…
A sum rule for determining |V_us| from a combination of hadronic tau decay and electroproduction data is discussed. Indications of problems with analogous, purely tau-decay-based analyses, most likely associated with slow convergence of the…
Dispersive approach to quantum chromodynamics is applied to the assessment of hadronic contributions to electroweak observables. The employed approach merges the corresponding perturbative input with intrinsically nonperturbative…
Recent progress in the determination of |V_us| employing strange hadronic tau-decay data are reported. This includes using the recent OPAL update of the strange spectral function, as well as augmenting the dimension-two perturbative…
The interpretation of results of recent tau decay determinations of |V_us|, which yield values ~3 sigma low compared to 3-family unitarity expectations, is complicated by the slow convergence of the relevant integrated D=2 OPE series. We…
The interplay between short- and long-distance contributions to the K_L-->mu+ mu- decay amplitude is analyzed. The long-distance piece is estimated using chiral perturbation theory techniques and large-N_C considerations, leading to a…
The long-distance electromagnetic radiative corrections to tau- -> pi- pi0 nu are re-evaluated. A meson dominance model is used to describe the emission of real photons in this decay. Results obtained for the hadronic spectrum and the decay…