Heavy quark symmetry behind $b \to c$ semileptonic sum rule

Le résumé fourni par la source

Lepton flavor universality violations in semileptonic $b \to c$ transitions have garnered attention over a decade. For $R_{H_c}={\rm{BR}}(H_b\to H_c τ\barν_τ)/{\rm{BR}}(H_b\to H_c \ell\barν_\ell)$ with $\ell$ being $e,\, μ$, a sum rule among $R_{D}$, $R_{D^*}$ and $R_{Λ_c}$ was proposed to check consistency in the experimental results independently of new physics models. We revisit this relation from the perspective of the heavy quark symmetry. We derive a sum rule holding exactly in the heavy quark limit and clarify how model-dependent corrections are introduced in a realistic situation.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.