Reevaluation of the hadronic vacuum polarisation contributions to the Standard Model predictions of the muon $$g-2$$ g - 2 and $${\alpha (m_Z^2)}$$ α ( m Z 2 ) using newest hadronic cross-section data

Abstract

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 $$e^+e^- \rightarrow \mathrm{hadrons}$$ cross-section data (among others) from the BABAR and VEPP-2000 experiments. For the muon $$(g-2)/2$$ we find for the lowest-order hadronic contribution $$(693.1 \pm 3.4)\times 10^{-10}$$ , improving the precision of our previous evaluation by 21%. The full Standard Model prediction differs by $$3.5\,\sigma $$ from the experimental value. The five-quark hadronic contribution to $$\alpha (m_Z^2)$$ is evaluated to be $$(276.0\pm 0.9)\times 10^{-4}$$ .