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arXiv · 2212.10300

Pseudoscalar-pole contributions to the muon $g-2$ at the physical point

Sebastian Burri·Gurtej Kanwar·Constantia Alexandrou·Simone Bacchio·Georg Bergner·Jacob Finkenrath·Andrew Gasbarro·Kyriakos Hadjiyiannakou·Karl Jansen·Bartosz Kostrzewa·Giannis Koutsou·Konstantin Ottnad·Marcus Petschlies·Ferenc Pittler·Fernanda Steffens·Carsten Urbach·Urs Wenger
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Abstract

Pseudoscalar-pole diagrams are an important component of estimates of the hadronic light-by-light (HLbL) contribution to the muon $g-2$. We report on our computation of the transition form factors $\mathcal{F}_{P \rightarrow \gamma^* \gamma^*}$ for the neutral pseudoscalar mesons $P=\pi^0$ and $\eta$. The calculation is performed using twisted-mass lattice QCD with physical quark masses. On the lattice, we have access to a broad range of (space-like) photon four-momenta and therefore produce form factor data complementary to the experimentally accessible single-virtual direction, which directly leads to an estimate of the pion- and $\eta$-pole components of the muon $g-2$. For the pion, our result for the $g-2$ contribution in the continuum is comparable with previous lattice and data-driven determinations, with combined relative uncertainties below $10\%$. For the $\eta$ meson, we report on a preliminary determination from a single lattice spacing.

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Sebastian Burri, Gurtej Kanwar, Constantia Alexandrou, Simone Bacchio, Georg Bergner, Jacob Finkenrath, Andrew Gasbarro, Kyriakos Hadjiyiannakou, Karl Jansen, Bartosz Kostrzewa, Giannis Koutsou, Konstantin Ottnad, Marcus Petschlies, Ferenc Pittler, Fernanda Steffens, Carsten Urbach, Urs Wenger. 2022-12-20. Pseudoscalar-pole contributions to the muon $g-2$ at the physical point. https://arxiv.org/abs/2212.10300

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