Reconciling hadronic and partonic analyticity in $b\to s\ell\ell$ transitions

Fuente: arXiv
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Main Authors: Hoferichter, Martin, Kubis, Bastian, Mutke, Simon
Format: Preprint
Published: 2026
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author Hoferichter, Martin
Kubis, Bastian
Mutke, Simon
author_facet Hoferichter, Martin
Kubis, Bastian
Mutke, Simon
contents Rare $B$-meson decays mediated by $b\to s\ell\ell$ transitions constitute sensitive probes of physics beyond the Standard Model, and have triggered considerable interest due to hints for deviations from the Standard-Model prediction. To establish a discrepancy beyond a reasonable doubt, control over the nonlocal matrix elements involving charm loops is essential, which, for large spacelike virtualities, can be constrained by an operator product expansion with coefficients known at two-loop order. We observe that the analytic structure of this partonic calculation, whose understanding is important to put forward rigorous parameterizations, follows from simple triangle topologies and demonstrate explicitly how dispersion relations are fulfilled even in the case of anomalous thresholds. Crucially, these anomalous contributions match onto the ones expected when considering hadronic degrees of freedom, proving that the partonic calculation does not miss anomalous effects and justifying its use in regions of parameter space in which a perturbative description applies.
format Preprint
id arxiv_https___arxiv_org_abs_2604_01284
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Reconciling hadronic and partonic analyticity in $b\to s\ell\ell$ transitions
Hoferichter, Martin
Kubis, Bastian
Mutke, Simon
High Energy Physics - Phenomenology
High Energy Physics - Experiment
Nuclear Theory
Rare $B$-meson decays mediated by $b\to s\ell\ell$ transitions constitute sensitive probes of physics beyond the Standard Model, and have triggered considerable interest due to hints for deviations from the Standard-Model prediction. To establish a discrepancy beyond a reasonable doubt, control over the nonlocal matrix elements involving charm loops is essential, which, for large spacelike virtualities, can be constrained by an operator product expansion with coefficients known at two-loop order. We observe that the analytic structure of this partonic calculation, whose understanding is important to put forward rigorous parameterizations, follows from simple triangle topologies and demonstrate explicitly how dispersion relations are fulfilled even in the case of anomalous thresholds. Crucially, these anomalous contributions match onto the ones expected when considering hadronic degrees of freedom, proving that the partonic calculation does not miss anomalous effects and justifying its use in regions of parameter space in which a perturbative description applies.
title Reconciling hadronic and partonic analyticity in $b\to s\ell\ell$ transitions
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
Nuclear Theory
url https://arxiv.org/abs/2604.01284