An update of the HLS estimate of the muon g−2
By Maurice Benayoun, P. David, L. DelBuono, F. Jegerlehner. 2012
140 citations recorded by the source corpus.
A global fit of parameters allows us to pin down the Hidden Local Symmetry (HLS) effective Lagrangian, which we apply for the prediction of the leading hadronic vacuum polarization contribution to the muon g−2. The latter is dominated by the annihilation channel e+e−→π+π−, for which data are available by scan (CMD-2 & SND) and ISR (KLOE-2008, KLOE-2010 & BaBar) experiments. It is well known that the different data sets are not in satisfactory agreement. In fact it is possible to fix the model parameters without using the π+π− data, by using instead the dipion spectra measured in the τ-decays together with experimental spectra for the π0γ, ηγ, π+π−π0, K+K−, $K^{0}\overline{K^{0}}$ final states, supplemented by specific meson decay properties. Among these, the accepted decay width for ρ0→e+e− and the partial widths and phase information for the ω/ϕ→π+π− transitions, are considered. It is then shown that, relying on this global data set, the HLS model, appropriately broken, allows to predict accurately the pion form factor below 1.05 GeV. It is shown that the data samples provided by CMD-2, SND and KLOE-2010 behave consistently with each other and with the other considered data. Consistency problems with the KLOE-2008 and BaBar data samples are substantiated. “All data” global fits are investigated by applying reweighting the conflicting data sets. Constraining to our best fit, the broken HLS model yields associated with a very good global fit probability. Correspondingly, we find that $\Delta a_{\mu}=a_{\mu}^{\rm exp}-a_{\mu}^{\rm th}$ exhibits a significance ranging between 4.7 and 4.9σ.
Subfields: Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/42ff60fa2853b64db4a3c84c249ef606de81ac0c
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In Nuclear and High Energy Physics
Citations in the corpus
- A Call for New Physics : The Muon Anomalous Magnetic Moment and Lepton Flavor Violation (2016, background): “results on the lowest-order hadronic evaluation, the difference between the SM prediction and the experimental value becomes larger yielding a significance of over 4σ [116, 117].”