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Semitauonic b-hadron decays: A lepton flavor universality laboratory

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arxiv 2101.08326 v2 pith:HONOZQG3 submitted 2021-01-20 hep-ex hep-ph

Semitauonic b-hadron decays: A lepton flavor universality laboratory

classification hep-ex hep-ph
keywords lfuvsemitauonicdecaysexperimentalflavorfuturehadronlepton
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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The study of lepton flavor universality violation (LFUV) in semitauonic $b$-hadron decays has become increasingly important in light of longstanding anomalies in their measured branching fractions, and the very large datasets anticipated from the LHC and Belle II. In this review, we undertake a comprehensive survey of the experimental environments and methodologies for semitauonic LFUV measurements at the $B$-factories and LHCb, along with a concise overview of the theoretical foundations and predictions for a wide range of semileptonic decay observables. We proceed to examine the future prospects to control systematic uncertainties down to the percent level, matching the precision of Standard Model (SM) predictions. Furthermore, we discuss new perspectives and caveats on combinations of the LFUV data and revisit the world averages for the ${\cal R}(D^{(*)})$ ratios. Here we demonstrate that different treatments for the correlations of uncertainties from $D^{**}$ excited states can vary the current $3\sigma$ tension with the SM within a $1\sigma$ range. Prior experimental overestimates of $D^{**}\tau\nu$ contributions may further exacerbate this. The precision of future measurements is also estimated; their power to exploit full differential information, and solutions to the inherent difficulties in self-consistent new physics interpretations of LFUV observables, are briefly explored.

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Cited by 7 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

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    hep-ph 2026-04 unverdicted novelty 6.0

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  3. Lifting Effective-Field-Theory Degeneracies in Semileptonic Heavy-Baryon Decays

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    hep-ph 2026-07 unverdicted novelty 4.0

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    hep-ph 2026-06 unverdicted novelty 4.0

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