Isospin Breaking in the Relation Between the tau-->nu_tau pi pi and e^+e^- -->pi^+ pi^- Versions of |F_π(s)|^2$ and Implications for (g-2)_mu

Abstract

We investigate two points related to existing treatments of isospin-breaking corrections to the CVC relation between the e^+e^- --> pi^+ pi^- cross-section and dGamma[tau^- --> nu_tau pi^- pi^0]/ds. Implications for the value of the hadronic contribution to a_mu =(g-2)_mu /2 based on those analyses incorporating hadronic tau decay data are also considered. We conclude that the uncertainty on the isospin-breaking correction which must be applied to the tau decay data should be significantly increased, and that the central value of the rho-omega ``mixing'' contribution to this correction may be significantly smaller than indicated by the present standard determination. Such a shift would contribute to reducing the discrepancy between the tau- and electroproduction-based determinations of the leading order hadronic contribution to a_mu.

15 pages, 1 figure

References in corpus (4)

• Measurement of $\sigma (e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\gamma )$ and extraction of $\sigma (e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-})$ below 1 {\rm GeV} with the KLOE detector
• The Standard Model Prediction of the Muon Anomalous Magnetic Moment
• Measurement of the muon anomaly to high and even higher precision
• Chiral Meson Physics at Two Loops

Cited by in corpus (16)

• The Muon g-2
• The Discrepancy Between tau and e+e- Spectral Functions Revisited and the Consequences for the Muon Magnetic Anomaly
• Charge Symmetry Breaking and QCD
• The Dipion Mass Spectrum In e+e- Annihilation and tau Decay: A Dynamical (rho0, omega, phi) Mixing Approach
• Electron, muon and tau magnetic moments: a theoretical update
• Consequences of the BaBar e^+e^- --> pi^+pi^- Measurement for the Determination of Model-Dependent rho-omega Mixing Effects in Pi_{ρω}(m_ρ^2) and (g-2)_mu
• Models of Isospin Breaking in the Pion Form Factor: Consequences for the Determination of Pi_{ρω}(m_rho^2) and (g-2)_mu/2
• Prospects for e+e- physics at Frascati between the phi and the psi
• A ChPT estimate of the strong-isospin-breaking contribution to the anomalous magnetic moment of the muon
• Isospin breaking corrections in $2\pi$ production in tau decays and $e^{+}{e}^{-}$ annihilation: consequences for the muon $g-2$ and CVC tests
• A study of $\rho -\omega$ mixing in resonance chiral theory
• Few Body Reserch - Summary
• Baryonic content of the pion
• Tau data-driven evaluation of the Hadronic Vacuum Polarization
• OPE Constraints and the Leading Order Hadronic Contribution to (g-2)_mu
• Tau Data-Based Evaluations of the hadronic vacuum polarization contribution to the muon $g-2$