QCD improved determination of the hadronic contribution to the anomalous magnetic moment of the muon

TL;DR

This paper introduces a QCD-based method to more accurately determine the hadronic contribution to the muon's anomalous magnetic moment by reducing reliance on experimental data in a specific energy range.

Contribution

It presents a novel approach using polynomial subtraction and complex contour evaluation to improve the precision of hadronic contribution calculations in a_mu.

Findings

Calculated a_mu^had(LO) = (701.3 +/- 6.4) x 10^-10

Recalculated a_mu^had(NLO) = (-10.3 +/- 0.2) x 10^-10

Total a_mu = (11 659 185.6 +/- 6.4_had +/- 3.5_LBL +/- 0.4_QED+EW) x 10^-10

Abstract

We present the results of a new evaluation of the anomalous magnetic moment a_mu=(g_mu-2)/2 of the muon where the role of input data needed in the evaluation is lowered in the interval between 1.2 and 3.0 GeV below charm threshold. This is achieved by decreasing the size of the weight function in the dispersion integral over the experimental ratio R(s) by subtracting a polynomial from the weight function which mimics its energy dependence in that given energy interval. In order to compensate for this subtraction, the same polynomial weight integral is added again but is now evaluated on a circular contour in the complex plane using QCD and global duality. For the hadronic contribution to the shift in the anomalous magnetic moment of the muon we obtain a_mu^had(LO) = (701.3 +/- 6.4) x 10^-10 at leading order in the electromagnetic coupling. In addition, using the same procedure, we recalculate the next-to-leading contribution a_mu^had(NLO) = (-10.3 +/- 0.2) x 10^-10. Including QED, electroweak, and light-by-light contribution, we obtain a value a_mu = (11 659 185.6 +/- 6.4_had +/- 3.5_LBL +/- 0.4_QED+EW) x 10^-10.