Holographic Calculation of Semileptonic Form Factors and the Isgur--Wise Function for B(s)→ D(s) Decays
Abstract
We present a holographic analysis of the semileptonic decays B → D ℓ ν̅ℓ and Bs → Ds ℓ ν̅ℓ within the Softwall Model (SWM) and the Non-Quadratic Softwall Model (NQSWM). We extract the Isgur-Wise function from the overlap integral of bulk wavefunctions, with model parameters fixed by the heavy-light meson spectra. We impose Heavy Quark Symmetry (HQS) at zero recoil and address the apparent paradox of a non-conserved electroweak current dual to a massless bulk vector field. We argue that the non-conservation, arising from explicit flavor-- symmetry breaking by quark masses, does not generate an anomalous dimension. Hence the bulk field remains massless, and the non-conservation is \emph{encoded} in the independent boundary couplings g+ and g-. Our predictions for the branching fractions are in good agreement with LHCb data for Bs → Ds decays. The lepton-flavor universality ratios R(D) and R(Ds) are consistent with Standard Model and lattice QCD predictions. We find that the holographic models reproduce the universality of the Isgur-Wise function near zero recoil, while discrepancies at maximum recoil suggest that a more complete treatment of higher-order 1/mQ corrections is needed.
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BibTeX
@misc{contreras2026holographic,
title = {{Holographic Calculation of Semileptonic Form Factors and the Isgur--Wise Function for $B_(s)\to D_(s)$ Decays}},
author = {Miguel Angel Martin Contreras and Alfredo Vega},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.28287},
eprint = {2610.28287},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.28287},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Holographic Calculation of Semileptonic Form Factors and the Isgur--Wise Function for B_(s)→ D_(s) Decays
AU - Miguel Angel Martin Contreras
AU - Alfredo Vega
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2610.28287
UR - https://arxiv.org/abs/2610.28287
AB - We present a holographic analysis of the semileptonic decays B → D ℓ ν̅_ℓ and B_s → D_s ℓ ν̅_ℓ within the Softwall Model (SWM) and the Non-Quadratic Softwall Model (NQSWM). We extract the Isgur-Wise function from the overlap integral of bulk wavefunctions, with model parameters fixed by the heavy-light meson spectra. We impose Heavy Quark Symmetry (HQS) at zero recoil and address the apparent paradox of a non-conserved electroweak current dual to a massless bulk vector field. We argue that the non-conservation, arising from explicit flavor-- symmetry breaking by quark masses, does not generate an anomalous dimension. Hence the bulk field remains massless, and the non-conservation is \emph{encoded} in the independent boundary couplings g_+ and g_-. Our predictions for the branching fractions are in good agreement with LHCb data for B_s → D_s decays. The lepton-flavor universality ratios R(D) and R(D_s) are consistent with Standard Model and lattice QCD predictions. We find that the holographic models reproduce the universality of the Isgur-Wise function near zero recoil, while discrepancies at maximum recoil suggest that a more complete treatment of higher-order 1/m_Q corrections is needed.
ER -