More than a Lifetime: Towards Precision Predictions for B-Meson Decays in the Standard Model and Beyond
Abstract
This thesis investigates B-meson lifetimes as probes of Standard Model (SM) dynamics and physics beyond the SM (BSM), employing the Heavy Quark Expansion (HQE) and light-cone sum rules (LCSR). Within the HQE, we calculate at leading order in QCD the complete dimension-seven two-quark contributions to the CKM-favoured non-leptonic transitions b→ cu̅d and b→ cc̅s, providing analytical Wilson coefficients for the 1/mb4 corrections. We then extend the dimension-six Darwin contribution to a model-independent BSM framework, deriving the Wilson coefficients through order 1/mb3 for a general non-leptonic effective Hamiltonian. We also determine the corresponding dimension-six four-quark weak annihilation contributions. As a special case, our results provide previously missing dimension-five and dimension-six contributions induced by SM QCD-penguin operators. Finally, we investigate B-mesogenesis, which connects the cosmic matter-antimatter asymmetry and dark matter to exotic B-meson decays. We study inclusive decay rates and lifetime ratios within the HQE and exclusive B+→ pψ decays using LCSR. Comparisons with experimental constraints from BaBar, Belle and Belle II restrict the allowed parameter space. We also identify kinematic regions where power-suppressed contributions exceed the leading terms, highlighting limitations of the HQE. Together, these studies advance the theoretical understanding of heavy-hadron lifetimes, strengthen the bridge between precision flavour physics and physics beyond the SM, and open new avenues for probing the interplay between heavy-quark dynamics and the dark sector.
Versions
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BibTeX
@misc{mohamed2026more,
title = {{More than a Lifetime: Towards Precision Predictions for $B$-Meson Decays in the Standard Model and Beyond}},
author = {Ali Mohamed},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.25311},
eprint = {2610.25311},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.25311},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - More than a Lifetime: Towards Precision Predictions for B-Meson Decays in the Standard Model and Beyond
AU - Ali Mohamed
PY - 2026
DA - 2026/10/18
PB - arXiv
DO - 10.48550/arxiv.2610.25311
UR - https://arxiv.org/abs/2610.25311
AB - This thesis investigates B-meson lifetimes as probes of Standard Model (SM) dynamics and physics beyond the SM (BSM), employing the Heavy Quark Expansion (HQE) and light-cone sum rules (LCSR). Within the HQE, we calculate at leading order in QCD the complete dimension-seven two-quark contributions to the CKM-favoured non-leptonic transitions b→ cu̅d and b→ cc̅s, providing analytical Wilson coefficients for the 1/m_b^4 corrections. We then extend the dimension-six Darwin contribution to a model-independent BSM framework, deriving the Wilson coefficients through order 1/m_b^3 for a general non-leptonic effective Hamiltonian. We also determine the corresponding dimension-six four-quark weak annihilation contributions. As a special case, our results provide previously missing dimension-five and dimension-six contributions induced by SM QCD-penguin operators. Finally, we investigate B-mesogenesis, which connects the cosmic matter-antimatter asymmetry and dark matter to exotic B-meson decays. We study inclusive decay rates and lifetime ratios within the HQE and exclusive B^+→ pψ decays using LCSR. Comparisons with experimental constraints from BaBar, Belle and Belle II restrict the allowed parameter space. We also identify kinematic regions where power-suppressed contributions exceed the leading terms, highlighting limitations of the HQE. Together, these studies advance the theoretical understanding of heavy-hadron lifetimes, strengthen the bridge between precision flavour physics and physics beyond the SM, and open new avenues for probing the interplay between heavy-quark dynamics and the dark sector.
ER -