Inclusive B decays, lifetimes, and |Vcb|: a unified heavy-quark expansion analysis
Abstract
We present a global HQE analysis of inclusive semileptonic B̅ → Xc l ν̅ℓ moments, partial branching fractions, and B+, B0 lifetime observables. Our fit setup follows a new approach where perturbative scales are treated as correlated nuisance parameters, while missing higher-order power corrections are assessed through order-by-order fits up to O(1/mb5). In the default scenario, we find |Vcb| = (42.32 ± 0.28|fit ± 0.10|h.o.)× 10−3 = (42.32 ± 0.30) × 10−3 and ℬ(B̅ → Xc ℓ ν̅ℓ) = (10.91 ± 0.11|fit ± 0.21|h.o.)%. For the lifetimes we obtain τB+ = 1.89+0.04−0.22 ps and τB0 = 1.74+0.03−0.23 ps, where the strongly asymmetric uncertainty is dominated by the perturbative scale variation of the non-leptonic width. Our predictions are in agreement with previous predictions and the corresponding widths lie $1.1−1.2,σ$ below the measurements. For the lifetime ratio, we find τB+/τB0 = 1.082+0.031−0.013 which agrees with experiment. For the full dataset of q2, Eℓ and MX moments, we obtain a poor fit quality, which we investigate using a leave-one-out study. In light of the persisting |Vcb| puzzle, new correlated moment measurements as well as updated branching ratio measurements are highly encouraged.
Related
- Three-loop QCD corrections to heavy-to-light form factors and applications to inclusive B decays
- Mixing-angle sensitivity of inclusive $Ξ_{bc} $ and Ωbc lifetimes
- Measurements of the inclusive Branching fractions of the Ds+ → η(η′) X decays
- Photon-Tagged Energy Flow in Inclusive Endpoint B Decays
- Photon-tagged energy flow in inclusive endpoint B decays
BibTeX
@misc{fael2026inclusive,
title = {{Inclusive $B$ decays, lifetimes, and $|V_cb|$: a unified heavy-quark expansion analysis}},
author = {Matteo Fael and Ilija S. Milutin and Markus Prim and K. Keri Vos},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.28752},
eprint = {2609.28752},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.28752},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Inclusive B decays, lifetimes, and |V_cb|: a unified heavy-quark expansion analysis
AU - Matteo Fael
AU - Ilija S. Milutin
AU - Markus Prim
AU - K. Keri Vos
PY - 2026
DA - 2026/09/23
PB - arXiv
DO - 10.48550/arxiv.2609.28752
UR - https://arxiv.org/abs/2609.28752
AB - We present a global HQE analysis of inclusive semileptonic B̅ → X_c l ν̅_ℓ moments, partial branching fractions, and B^+, B^0 lifetime observables. Our fit setup follows a new approach where perturbative scales are treated as correlated nuisance parameters, while missing higher-order power corrections are assessed through order-by-order fits up to O(1/m_b^5). In the default scenario, we find |V_cb| = (42.32 ± 0.28|_fit ± 0.10|_h.o.)× 10^−3 = (42.32 ± 0.30) × 10^−3 and ℬ(B̅ → X_c ℓ ν̅_ℓ) = (10.91 ± 0.11|_fit ± 0.21|_h.o.)%. For the lifetimes we obtain τ_B^+ = 1.89^+0.04_−0.22 ps and τ_B^0 = 1.74^+0.03_−0.23 ps, where the strongly asymmetric uncertainty is dominated by the perturbative scale variation of the non-leptonic width. Our predictions are in agreement with previous predictions and the corresponding widths lie $1.1−1.2,σ$ below the measurements. For the lifetime ratio, we find τ_B^+/τ_B^0 = 1.082^+0.031_−0.013 which agrees with experiment. For the full dataset of q^2, E_ℓ and M_X moments, we obtain a poor fit quality, which we investigate using a leave-one-out study. In light of the persisting |V_cb| puzzle, new correlated moment measurements as well as updated branching ratio measurements are highly encouraged.
ER -