Are Subleading Effects Really Subleading? $B$-Meson Decays in Mesogenesis

Fuente: arXiv
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Main Author: Mohamed, Ali
Format: Preprint
Published: 2025
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author Mohamed, Ali
author_facet Mohamed, Ali
contents We calculate inclusive $B$-meson decay rates in the Mesogenesis framework, a model explaining baryogenesis and the existence of dark matter, using the Heavy Quark Expansion (HQE), up to the dimension-six two-quark Darwin term. By systematically studying the power-suppressed contributions, we identify regions of parameter space where subleading terms exceed the leading contribution, i.e., the free $b$-quark decay, highlighting the limits of the HQE in this BSM scenario. This behavior is reminiscent of the Standard Model only under artificially heavy charm masses, and can be used to study the HQE close to its breakdown. We further update the lower bounds on the exclusive decay mode $B^+ \to p^+ ψ$ by incorporating the fully HQE-corrected inclusive width in the ratio $Γ_{\mathrm{excl}}/Γ_{\mathrm{incl}}$. Extending the analysis from total decay rates to the lifetime ratio $τ(B_s)/τ(B_d)$, we find no additional constraints on the couplings beyond existing collider bounds, consistent with analogous results for $τ(B^+)/τ(B_d)$. We further compare the sensitivity of both lifetime ratios.
format Preprint
id arxiv_https___arxiv_org_abs_2511_04858
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Are Subleading Effects Really Subleading? $B$-Meson Decays in Mesogenesis
Mohamed, Ali
High Energy Physics - Phenomenology
High Energy Physics - Experiment
We calculate inclusive $B$-meson decay rates in the Mesogenesis framework, a model explaining baryogenesis and the existence of dark matter, using the Heavy Quark Expansion (HQE), up to the dimension-six two-quark Darwin term. By systematically studying the power-suppressed contributions, we identify regions of parameter space where subleading terms exceed the leading contribution, i.e., the free $b$-quark decay, highlighting the limits of the HQE in this BSM scenario. This behavior is reminiscent of the Standard Model only under artificially heavy charm masses, and can be used to study the HQE close to its breakdown. We further update the lower bounds on the exclusive decay mode $B^+ \to p^+ ψ$ by incorporating the fully HQE-corrected inclusive width in the ratio $Γ_{\mathrm{excl}}/Γ_{\mathrm{incl}}$. Extending the analysis from total decay rates to the lifetime ratio $τ(B_s)/τ(B_d)$, we find no additional constraints on the couplings beyond existing collider bounds, consistent with analogous results for $τ(B^+)/τ(B_d)$. We further compare the sensitivity of both lifetime ratios.
title Are Subleading Effects Really Subleading? $B$-Meson Decays in Mesogenesis
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2511.04858