Hadronic vacuum polarization contribution to the muon $g-2$ in holographic QCD

TL;DR

This paper assesses the hadronic vacuum polarization contribution to muon g-2 using holographic QCD models, comparing results with dispersive and lattice methods, and discusses implications for hadronic light-by-light calculations.

Contribution

It provides the first detailed comparison of holographic QCD predictions with data-driven and lattice results for muon g-2 contributions, highlighting model limitations and consistency.

Findings

Holographic models yield results comparable to dispersive and lattice approaches.

Hard-wall model matches data-driven results when adjusted for NLO effects.

Insights gained inform the modeling of hadronic light-by-light contributions.

Abstract

We evaluate the leading-order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon with two light flavors in minimal hard-wall and soft-wall holographic QCD models, as well as in simple generalizations thereof, and compare with the rather precise results available from dispersive and lattice approaches. While holographic QCD cannot be expected to shed light on the existing small discrepancies between the latter, this comparison in turn provides useful information on the holographic models, which have been used to evaluate hadronic light-by-light contributions where errors in data-driven and lattice approaches are more sizable. In particular, in the hard-wall model that has recently been used to implement the Melnikov-Vainshtein short-distance constraint on hadronic light-by-light contributions, a matching of the hadronic vacuum polarization to the data-driven approach points to the same correction of parameters that has been proposed recently in order to account for next-to-leading order effects.