相关论文: On the longitudinal contributions to hadronic tau …
The talk covers three contributions on (i) the final measurement of branching ratios and spectral functions of t decays using the full LEP-I data from ALEPH, (ii) a preliminary measurement of the t hadronic branching ratios from DELPHI and…
Non-perturbative effects have a small but non-trivial impact on the determination of the strong coupling from hadronic $\tau$ decay data. Several approaches have been proposed to take these into account, the two most important of which are…
We discuss the extraction of alpha_s using isovector hadronic tau decay data and sum rules constructed specifically to suppress contributions associated with poorly known higher dimension condensates. We show, first, that problems with the…
Partial sum rules are widely used in physics to separate low- and high-energy degrees of freedom of complex dynamical systems. Their application, though, is challenged in practice by the always finite spectrometer bandwidth and is often…
In the chiral limit, the $D=6$ contribution to the Operator Product Expansion (OPE) of the $\mathrm{VV-AA}$ correlator of quark currents only depends on two vacuum condensates, which can be related to hadronic matrix elements associated to…
We review recent work to determine the strange quark mass m_s as well as the proposal to determine |V_{us}| using hadronic tau decay data. The recent update of the strange spectral function by OPAL and their moments of the invariant mass…
General one-loop contributions to the decay amplitudes $H\rightarrow \nu_l\bar{\nu}_l\gamma$ are presented, considering all possible contributions of additional heavy vector gauge bosons, fermions, and charged (and also neutral) scalar…
After discussing difficulties in determining $\alpha_s$ from tau decay due to the existence of Duality Violations and the associated asymptotic nature of the OPE, we describe a new determination based on an improved vector isovector…
We reevaluate the hadronic contribution to the running of the QED fine structure constant \aqed at $s=M_{\rm Z}^2$. We use data from \ee\ annihilation and $\tau$ decays at low energy and at the $q\bar{q}$ thresholds, where resonances occur.…
We perform a global analysis of exclusive hadronic tau decays into one and two mesons using the low-energy limit of the Standard Model Effective Field Theory up to dimension six, assuming left-handed neutrinos. A controlled theoretical…
Recent experimental results on hadronic tau decays into strange particles by the OPAL collaboration are employed to determine V_us and m_s from moments of the invariant mass distribution. Our results are V_us = 0.2208+-0.0034 and m_s(2 GeV)…
The dispersive approach to QCD is applied to the study of the inclusive tau lepton hadronic decay. This approach provides the unified integral representations for the hadronic vacuum polarization function, related R function, and Adler…
Pion-kaon ($\pi K$) pairs occur frequently as final states in heavy-particle decays. A consistent treatment of $\pi K$ scattering and production amplitudes over a wide energy range is therefore mandatory for multiple applications: in…
A theoretical description of the differential decay spectrum for the decay tau- -> nu_tau K_S pi-, which is based on the contributing K pi vector and scalar form factors F_+^{K pi}(s) and F_0^{K pi}(s) being calculated in the framework of…
Predictions for decay rates and distributions for $\tau$ decays into final states with kaons are discussed and compared with recent measurements. Special emphasis is put on new constraints for the vector current contribution in the $KK\pi$…
We describe the spectra and decays of pi pi and pi K atoms within a non-relativistic effective field theory. The evaluations of the energy shifts and widths are performed at next-to-leading order in isospin symmetry breaking. The prediction…
Gaussian sum-rules, which are related to a two-parameter Gaussian-weighted integral of a hadronic spectral function, are able to examine the possibility that more than one resonance makes a significant contribution to the spectral function.…
Sum rule tests are performed on the spectral data for (i) flavor 'ud' vector- current-induced hadronic tau decays and (ii) e^+ e^- hadroproduction, in the region below s~3-4 GeV^2, where discrepancies exist between the isospin-…
Short and long distance contributions to the exclusive B-decays into various K-resonances and dileptons, i.e. B --> Ki l l ( l = e, mu , nu ), are examined. The heavy quark effective theory has been used to calculate the hadronic matrix…
We provide an overview of recent determinations of the strong coupling, $\alpha_s$, from hadronic $\tau$ decays. We contrast two analysis methods, the "truncated-OPE approach" and the "DV-model approach," highlighting the assumptions going…