Theoretical determination of the hadronic (g-2) of the muon

Abstract

An approach is discussed on the determination of the leading order hadronic contribution to the muon anomaly, $a_{\mu }^{HAD}$, based entirely on theory. This method makes no use of $e^{+}{e}^{-}$ annihilation data, a likely source of the current discrepancy between theory and experiment beyond the $3\sigma$ level. What this method requires is essentially knowledge of the first derivative of the vector current correlator at zero-momentum. In the heavy-quark sector this is obtained from the well known heavy quark expansion in perturbative QCD, leading to values of $a_{\mu }^{HAD}$ in the charm- and bottom-quark region which were fully confirmed by later lattice QCD (LQCD) results. In the light-quark sector, using recent preliminary LQCD results for the first derivative of the vector current correlator at zero-momentum leads to the value $a_{\mu }^{HAD}=(729-871)\times 10^{-10}$, which is significantly larger than values obtained from using $e^{+}{e}^{-}$ data. A separate approach based on the operator product expansion (OPE), and designed to quench the contribution of these data, reduces the discrepancy by at least 40\%. In addition, it exposes a tension between the OPE and $e^{+}{e}^{-}$ data, thus suggesting the blame for the discrepancy on the latter.

Invited talk at the Workshop on Determination of the Fundamental Parameters in QCD, Mainz Institute of Theoretical Physics, Johannes Gutenberg University of Mainz. To be published in Mod. Phys. Lett. A

References in corpus (8)

• Hadronic Z- and tau-Decays in Order alpha_s^4
• Charm and Bottom Quark Masses from Perturbative QCD
• The strong coupling from the revised ALEPH data for hadronic $\tau$ decays
• Four-loop moments of the heavy quark vacuum polarization function in perturbative QCD
• Low energy moments of heavy quark current correlators at four loops
• The ${\rm Y}$ and ${{\rm Y}}^{\prime }$ Leptonic Widths, $a_{\mu }^b$ and $m_b$ from full lattice QCD
• Possible duality violations in tau decay and their impact on the determination of alpha_s
• The strange and charm quark contributions to the anomalous magnetic moment of the muon from lattice QCD

Cited by in corpus (2)

• A Call for New Physics : The Muon Anomalous Magnetic Moment and Lepton Flavor Violation
• Vector two-point functions in finite volume using partially quenched chiral perturbation theory