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arXiv · 2106.05660

Small-momentum expansion of heavy-quark correlators in the large-$\beta_0$ limit and $\alpha_s$ extractions

Diogo Boito·Vicent Mateu·Marcus V. Rodrigues
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Abstract

We calculate the small-momentum expansion of vector, axial-vector, scalar, and pseudo-scalar heavy-quark current correlators in the large-$\beta_0$ limit of QCD, extending the analysis of Grozin and Sturm beyond the vector current. Our results are used to study the higher-order behaviour of dimensionless ratios of vector and pseudo-scalar moments used for the precise extraction of the strong coupling, $\alpha_s$, from relativistic quarkonium sum rules and lattice data, respectively. We show that these ratios benefit from a partial cancellation of the leading renormalon singularities. Our results can guide the design of combinations of moments with improved perturbative behaviour.

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Diogo Boito, Vicent Mateu, Marcus V. Rodrigues. 2021-06-10. Small-momentum expansion of heavy-quark correlators in the large-$\beta_0$ limit and $\alpha_s$ extractions. https://doi.org/10.1007/jhep08(2021)027

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