A Phenomenological Study of Semileptonic B+ and Bs0 Decays into Axial-Vector Mesons (D1(2420), D1′(2430), Ds1(2460), and Ds1′(2536)) within the Standard Model
Abstract
We study semileptonic B meson decays B+ → D1(′)ℓ+νℓ and Bs0 → Ds1−(′)ℓ+νℓ, where ℓ=μ,τ. The final state axial vector mesons are treated as mixtures of the heavy quark basis states with light degree of freedom angular momenta jℓ=1/2 and jℓ=3/2, parametrized by the mixing angle θD1. Using form factors obtained in the covariant light front quark model, we analyze the dependence of various observables on θD1 such as polarized and unpolarized branching ratios, the lepton forward-backward asymmetry, the longitudinal polarization fraction, and the lepton flavor universality ratios. In addition, we also discuss correlations among different observables. We study these observables in the experimentally motivated mixing angle regions as well as over a wider range of θD1. Our results show that branching ratios and other observables are sensitive to the axial-vector mixing structure. These predictions provide useful Standard Model benchmarks for future measurements of semileptonic B(s) decays into orbitally excited mesons and may help to clarify the long standing 1/2 vs. 3/2 puzzle through semileptonic B decays.
Versions
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BibTeX
@misc{khan2026phenomenological,
title = {{A Phenomenological Study of Semileptonic $B^+$ and $B_s^0$ Decays into Axial-Vector Mesons $\big(D_1(2420),\, D_1^\prime(2430),\, D_s1(2460),\, \textand D_s1^\prime(2536)\big)$ within the Standard Model}},
author = {Rana Khan and Qazi Maaz Us Salam and Zohaib Aarfi and Ishtiaq Ahmed},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.12065},
eprint = {2605.12065},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.12065},
}
RIS
TY - UNPB
TI - A Phenomenological Study of Semileptonic B^+ and B_s^0 Decays into Axial-Vector Mesons (D_1(2420), D_1^′(2430), D_s1(2460), and D_s1^′(2536)) within the Standard Model
AU - Rana Khan
AU - Qazi Maaz Us Salam
AU - Zohaib Aarfi
AU - Ishtiaq Ahmed
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2605.12065
UR - https://arxiv.org/abs/2605.12065
AB - We study semileptonic B meson decays B^+ → D_1^(′)ℓ^+ν_ℓ and B_s^0 → D_s1^−(′)ℓ^+ν_ℓ, where ℓ=μ,τ. The final state axial vector mesons are treated as mixtures of the heavy quark basis states with light degree of freedom angular momenta j_ℓ=1/2 and j_ℓ=3/2, parametrized by the mixing angle θ_D_1. Using form factors obtained in the covariant light front quark model, we analyze the dependence of various observables on θ_D_1 such as polarized and unpolarized branching ratios, the lepton forward-backward asymmetry, the longitudinal polarization fraction, and the lepton flavor universality ratios. In addition, we also discuss correlations among different observables. We study these observables in the experimentally motivated mixing angle regions as well as over a wider range of θ_D_1. Our results show that branching ratios and other observables are sensitive to the axial-vector mixing structure. These predictions provide useful Standard Model benchmarks for future measurements of semileptonic B_(s) decays into orbitally excited mesons and may help to clarify the long standing 1/2 vs. 3/2 puzzle through semileptonic B decays.
ER -