Reevaluation of the Hadronic Contributions to the Muon g-2 and to alpha (M^2_Z) - IN2P3 - Institut national de physique nucléaire et de physique des particules Accéder directement au contenu
Article Dans Une Revue European Physical Journal C: Particles and Fields Année : 2011

Reevaluation of the Hadronic Contributions to the Muon g-2 and to alpha (M^2_Z)

Résumé

We reevaluate the hadronic contributions to the muon magnetic anomaly, and to the running of the electromagnetic coupling constant at the Z-boson mass. We include new pi+pi- cross-section data from KLOE, all available multi-hadron data from BABAR, a reestimation of missing low-energy contributions using results on cross sections and process dynamics from BABAR, a reevaluation of all experimental contributions using the software package HVPTools, together with a reanalysis of inter-experiment and inter-channel correlations, and a reevaluation of the continuum contributions from perturbative QCD at four loops. These improvements lead to a decrease in the hadronic contributions with respect to earlier evaluations. For the muon g-2 we find lowest-order hadronic contributions of (692.3 +- 4.2) 10^-10 and (701.5 +- 4.7) 10^-10 for the e+e- based and tau-based analyses, respectively, and full Standard Model predictions that differ by 3.6 sigma and 2.4 sigma from the experimental value. For the e+e- based five-quark hadronic contribution to alpha(MZ) we find Delta_alpha_had[5](MZ)=(274.9 +- 1.0) 10^-4. The reduced electromagnetic coupling strength at MZ leads to an increase by 12 GeV in the most probable Higgs boson mass obtained by the standard Gfitter fit to electroweak precision data.

Dates et versions

in2p3-00529219 , version 1 (25-10-2010)

Identifiants

Citer

M. Davier, A. Hoecker, B. Malaescu, Zhiqing Zhang. Reevaluation of the Hadronic Contributions to the Muon g-2 and to alpha (M^2_Z). European Physical Journal C: Particles and Fields, 2011, 71, 1515 (13 p.). ⟨10.1140/epjc/s10052-010-1515-z⟩. ⟨in2p3-00529219⟩
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