Phenomenological study of diquark effects in B̅(s)0 → D(s)(*)+ L- decays
Abstract
Motivated by the deviations between experimental data and SM predictions for the branching fractions of B̅(s)0 → D(s)(*)+L- decays with L=π,K(*),ρ, we investigate whether the type-IV scalar diquark can offer a plausible explanation for them. By matching the renormalized amplitudes in the full theory onto those in the low-energy effective theory formulated in the diquark operator basis, we extract the corresponding Wilson coefficients up to NLO in αs at the NP scale μϕ=Mϕ. We then rewrite the obtained operators in the SM basis and apply the renormalization-group running to evolve the Wilson coefficients down to the hadronic scale μb=mb. For the hadronic matrix elements of the relevant NP operators, we employ the QCD factorization approach to evaluate the non-factorizable one-loop vertex corrections, and confront our theoretical predictions to the latest data to constrain the diquark parameter space. In the single-coupling case, we find that the purely left-handed coupling Δd(s)LL can reconcile the discrepancies at 1σ, while the mixed right-left coupling Δd(s)RL remains compatible with data only at about 2σ. Extending to the two-coupling case, we find viable parameter regions as long as Δd(s)LL≠ 0. Incorporating the LHCb measurement of the ratio Rπ/μνμ further reduces the allowed range of ΔdLL, but does not yield meaningful extra restriction on ΔdRL. Hence, while either Δd(s)LL or Δd(s)RL can separately provide an acceptable NP interpretation, our phenomenological results favor a scenario dominated by purely left-handed diquark-quark couplings. Finally, we present updated predictions for the branching fractions and the ratios R(s)L(*), which can be probed by forthcoming LHCb and Belle II measurements.
Related
- Spectra and nonleptonic decays of multiply heavy baryons in a finite-size quark-diquark model
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- Scalar diquark mass and quark–diquark potential from lattice QCD using the potential method with a static quark
- Diquark Correlators and Phase Structure in the Quark-Meson-Diquark Model beyond Mean Field
- Scalar diquark mass and quark--diquark potential from lattice QCD using the potential method with a static quark
BibTeX
@misc{cai2026phenomenological,
title = {{Phenomenological study of diquark effects in $\barB_(s)^0 \to D_(s)^(*)+ L^-$ decays}},
author = {Fang-Min Cai and Xin-Qiang Li and Tong-Kai Liu and Yan Shi and Ya-Dong Yang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.05958},
eprint = {2610.05958},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.05958},
}
RIS
TY - UNPB
TI - Phenomenological study of diquark effects in B̅_(s)^0 → D_(s)^(*)+ L^- decays
AU - Fang-Min Cai
AU - Xin-Qiang Li
AU - Tong-Kai Liu
AU - Yan Shi
AU - Ya-Dong Yang
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2610.05958
UR - https://arxiv.org/abs/2610.05958
AB - Motivated by the deviations between experimental data and SM predictions for the branching fractions of B̅_(s)^0 → D_(s)^(*)+L^- decays with L=π,K^(*),ρ, we investigate whether the type-IV scalar diquark can offer a plausible explanation for them. By matching the renormalized amplitudes in the full theory onto those in the low-energy effective theory formulated in the diquark operator basis, we extract the corresponding Wilson coefficients up to NLO in α_s at the NP scale μ_ϕ=M_ϕ. We then rewrite the obtained operators in the SM basis and apply the renormalization-group running to evolve the Wilson coefficients down to the hadronic scale μ_b=m_b. For the hadronic matrix elements of the relevant NP operators, we employ the QCD factorization approach to evaluate the non-factorizable one-loop vertex corrections, and confront our theoretical predictions to the latest data to constrain the diquark parameter space. In the single-coupling case, we find that the purely left-handed coupling Δ_d(s)^LL can reconcile the discrepancies at 1σ, while the mixed right-left coupling Δ_d(s)^RL remains compatible with data only at about 2σ. Extending to the two-coupling case, we find viable parameter regions as long as Δ_d(s)^LL≠ 0. Incorporating the LHCb measurement of the ratio R_π/μν_μ further reduces the allowed range of Δ_d^LL, but does not yield meaningful extra restriction on Δ_d^RL. Hence, while either Δ_d(s)^LL or Δ_d(s)^RL can separately provide an acceptable NP interpretation, our phenomenological results favor a scenario dominated by purely left-handed diquark-quark couplings. Finally, we present updated predictions for the branching fractions and the ratios R_(s)L^(*), which can be probed by forthcoming LHCb and Belle II measurements.
ER -