相关论文: Two-pion contribution to the muon magnetic moment
We discuss the decay tau^- -> nu_tau pi^- pi^0 gamma in terms of a model with the correct low-energy structure and with the relevant resonance degress of freedom. The nontrivial radiative dynamics becomes visible for large photon momenta…
We revisit the isospin-breaking and electromagnetic corrections to the decay $\tau^-\to\pi^-\pi^0\nu_\tau$, which allow its use as input in the two-pion contribution to the (leading order) hadronic vacuum polarization part of the muon…
We review the isospin-breaking and electromagnetic corrections to the $\tau^- \to \pi^- \pi^0 \nu_\tau$ decays, which are used as an input to the two-pion contributions to the hadronic vacuum polarization (at LO) of the anomalous magnetic…
We calculate the leading isospin-violating and electromagnetic corrections for the decay tau --> pi^0 pi nu_tau at low energies. The corrections are small but relevant for the inclusion of tau decay data in the determination of hadronic…
We calculate the leading isospin-violating and electromagnetic corrections for the decay tau -> pi^0 pi nu_tau at low energies. The corrections are small but relevant for the inclusion of tau decay data in the determination of hadronic…
We have reevaluated the hadronic contribution to the anomalous magnetic moment of the muon (g-2) and to the running of the QED fine structure constant alpha(s) at s=M_Z**2. We incorporated new data from hadronic tau decays, recently…
Recent calculations of the hadronic vacuum polarisation contribution are reviewed. The focus is put on the leading-order contribution to the muon magnetic anomaly involving $e^+e^-$ annihilation cross section data as input to a dispersion…
Following updates in the compilation of $e^+e^-\rightarrow{\rm hadrons}$ data, this work presents re-evaluations of the hadronic vacuum polarisation contributions to the anomalous magnetic moment of the electron ($a_e$), muon ($a_\mu$) and…
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…
Results on the lowest-order hadronic vacuum polarization contribution to the muon magnetic anomaly are presented. They are based on the latest published experimental data used as input to the dispersion integral. Thus recent results on tau…
In this work we focus on the evaluation of the leading-order hadronic vacuum polarization contribution from the $\pi\pi$ channel to the muon anomalous magnetic moment $a_\mu$ by using the experimental $\tau\to\pi\pi\nu_\tau$ data. The…
We present a systematic study of the hadronic contributions to the muon anomalous magnetic moment within several infrared-improved AdS/QCD models. The models are constrained by the pion decay constant and the $\rho$-meson mass and are shown…
We present a detailed analysis of $e^+e^-\to\pi^+\pi^-$ data up to $\sqrt{s}=1\,\text{GeV}$ in the framework of dispersion relations. Starting from a family of $\pi\pi$ $P$-wave phase shifts, as derived from a previous Roy-equation analysis…
Hadronic $\tau$ decays present an opportunity to determine the isovector part of the hadronic-vacuum-polarization contribution to the anomalous magnetic moment of the muon in a way complementary to $e^+e^-\to\text{hadrons}$ cross sections.…
We review the tau data-driven computation of Euclidean windows for the hadronic vacuum polarization contribution to the muon anomalous magnetic moment (a_mu), which agree with the lattice results, making the difference of the $e^+e^-$…
The largest error in the theoretical determination of the muon anomalous magnetic moment is due to the low-energy hadronic vacuum polarization, which cannot be calculated by perturbative QCD and requires nonperturbative techniques.…
At low energies hadronic vacuum polarization (HVP) is strongly dominated by two-pion intermediate states, which are responsible for about $70\%$ of the HVP contribution to the anomalous magnetic moment of the muon, $a_\mu^\text{HVP}$.…
We reevaluate the hadronic vacuum polarisation contributions to the muon magnetic anomaly and to the running of the electromagnetic coupling constant at the $Z$-boson mass. We include newest $e^+e^- \to$ hadrons cross-section data together…
A reliable calculation of radiative corrections to $\tau\to\pi\pi\nu_\tau$ decays is an important prerequisite for using hadronic $\tau$ decays for a data-driven evaluation of the hadronic-vacuum-polarization contribution to the anomalous…
We derive an analytic result for the pion pole contribution to the light-by-light scattering correction to the anomalous magnetic moment of the muon, $a_\mu = (g_\mu-2)/2$. Using the vector meson dominance model (VMD) for the pion…