OPE Constraints and the Leading Order Hadronic Contribution to (g-2)_mu

Abstract

OPE constraints are studied as a means of distinguishing between the versions of the I=1 vector spectral function extracted from (i) inclusive I=1 hadronic electroproduction cross-sections and (ii) inclusive I=1 hadronic tau decay data, with the goal of clarifying expectations for the leading order hadronic contribution to a_mu = (g-2)_mu /2 in the Standard Model. The constraints are shown to, at present, favor the tau decay data, and hence a Standard Model prediction for a_mu compatible with the BNL E821 experimental result. The relative role of the 2pi and 4pi contributions to the discrepancy between the integrated electroproduction results and the corresponding OPE constraints is also investigated, and the significance, in this context, of forthcoming re-measurements of the e^+e^- --> pi^+ pi^- pi^0 pi^0 cross-sections pointed out.

arXiv comment6 pages, 5 figures, prepared for the Proceedings of the 9th International Workshop on Tau Lepton Physics

References in corpus (17)

• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• Measurement of the Negative Muon Anomalous Magnetic Moment to 0.7 ppm
• Strong Coupling Constant with Flavour Thresholds at Four Loops in the MS-bar Scheme
• Confronting Spectral Functions from e+e- Annihilation and tau Decays: Consequences for the Muon Magnetic Moment
• 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
• Measurement of e+e- -> pi+pi- cross section with CMD-2 around rho-meson
• Study of e+e- --> pi+ pi- pi0 process using initial state radiation with BABAR
• Hadronic Structure in the Decay ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$
• Isospin Violation and the Magnetic Moment of the Muon
• Constraints on Hadronic Spectral Functions From Continuous Families of Finite Energy Sum Rules
• Improved Determination of the Electroweak Penguin Contribution to epsilon'/epsilon in the Chiral Limit
• QCD Condensates for the Light Quark V-A Correlator
• 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
• Constraints on the I=1 hadronic tau decay and e^+e^- --> hadrons data sets and implications for (g-2)_mu
• Measurement of the muon anomaly to high and even higher precision
• The Feynman-Wilson gas and the Lund model