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

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Main Authors: Kuberski, Simon, Cè, Marco, von Hippel, Georg, Meyer, Harvey B., Ottnad, Konstantin, Risch, Andreas, Wittig, Hartmut
Format: Preprint
Published: 2024
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author Kuberski, Simon
Cè, Marco
von Hippel, Georg
Meyer, Harvey B.
Ottnad, Konstantin
Risch, Andreas
Wittig, Hartmut
author_facet Kuberski, Simon
Cè, Marco
von Hippel, Georg
Meyer, Harvey B.
Ottnad, Konstantin
Risch, Andreas
Wittig, Hartmut
contents 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 $(a_μ^{\rm hvp})^{\rm SD}=68.85(14)_{\rm stat}\,(42)_{\rm syst}\cdot10^{-10}$, 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.
format Preprint
id arxiv_https___arxiv_org_abs_2401_11895
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hadronic vacuum polarization in the muon $g-2$: The short-distance contribution from lattice QCD
Kuberski, Simon
Cè, Marco
von Hippel, Georg
Meyer, Harvey B.
Ottnad, Konstantin
Risch, Andreas
Wittig, Hartmut
High Energy Physics - Lattice
High Energy Physics - Phenomenology
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 $(a_μ^{\rm hvp})^{\rm SD}=68.85(14)_{\rm stat}\,(42)_{\rm syst}\cdot10^{-10}$, 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.
title Hadronic vacuum polarization in the muon $g-2$: The short-distance contribution from lattice QCD
topic High Energy Physics - Lattice
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2401.11895