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arXiv · 2401.11895

Hadronic vacuum polarization in the muon $g-2$: The short-distance contribution from lattice QCD

Simon Kuberski·Marco Cè·Georg von Hippel·Harvey B. Meyer·Konstantin Ottnad·Andreas Risch·Hartmut Wittig
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Abstract

We present results for the short-distance window observable of the hadronic vacuum polarization contribution to the muon $g-2$, computed via the time-momentum representation (TMR) in lattice QCD. A key novelty of our calculation is the reduction of discretization effects by a suitable subtraction applied to the TMR kernel function, which cancels the leading $x_0^4$-behaviour at short distances. To compensate for the subtraction, one must substitute a term that can be reliably computed in perturbative QCD. We apply this strategy to our data for the vector current collected on ensembles generated with $2+1$ flavours of O($a$)-improved Wilson quarks at six values of the lattice spacing and pion masses in the range $130-420\,$MeV. Our estimate at the physical point contains a full error budget and reads $(a_\mu^{\rm hvp})^{\rm SD}=68.85(14)_{\rm stat}\,(42)_{\rm syst}\cdot10^{-10}$, which corresponds to a relative precision of 0.7\%. We discuss the implications of our result for the observed tensions between lattice and data-driven evaluations of the hadronic vacuum polarization.

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Simon Kuberski, Marco Cè, Georg von Hippel, Harvey B. Meyer, Konstantin Ottnad, Andreas Risch, Hartmut Wittig. 2024-01-22. Hadronic vacuum polarization in the muon $g-2$: The short-distance contribution from lattice QCD. https://arxiv.org/abs/2401.11895

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