Addressing the lightest S-wave strange K₀^*(700)/κ resonance in four-body semileptonic B̅_s⁰ → K⁰π⁺ ℓ^-ν̅_ℓ decays

@misc{huang2026addressing,
  title = {{Addressing the lightest $S$-wave strange $K_0^*(700)/κ$ resonance in four-body semileptonic $\barB_s^0 \to K^0π^+ \ell^-\barν_\ell$ decays}},
  author = {Dong Huang and Sheng-Bo Wu and Fang-Ping Peng and Long Zeng and Hai-Bing Fu},
  howpublished = {arXiv},
  year = {2026},
  month = jun,
  doi = {10.48550/arxiv.2606.24223},
  eprint = {2606.24223},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2606.24223},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Addressing the lightest S-wave strange K_0^*(700)/κ resonance in four-body semileptonic B̅_s^0 → K^0π^+ ℓ^-ν̅_ℓ decays
AU  - Dong Huang
AU  - Sheng-Bo Wu
AU  - Fang-Ping Peng
AU  - Long Zeng
AU  - Hai-Bing Fu
PY  - 2026
DA  - 2026/06/23
PB  - arXiv
DO  - 10.48550/arxiv.2606.24223
UR  - https://arxiv.org/abs/2606.24223
AB  - As the lightest strange scalar resonance, K_0^*(700) (also called κ) has a large width and resides close to the Kπ threshold, leading to a longstanding debate about its internal structure. Within the framework of the conventional quark-antiquark (qq̅) picture, this paper attempts to research the behaviors of K_0^*(700) resonance in the four-body final state decays. Firstly, we investigates the K_0^*(700) resonance one twist-2 and two twist-3 light-cone distribution amplitudes (LCDAs), {\it i.e.} ϕ_2;K_0^*(700)(x, μ) and ϕ_3;K_0^*(700)^p;σ(x, μ) by constructing light-cone harmonic oscillator model. For the longitudinal distribution characteristics of the twist-2 LCDA, two typical parametrization schemes, {\it i.e.} φ_2;K_0^*(700)^(S1)(x) and φ_2;K_0^*(700)^(S2)(x), are adopted in this paper. Meanwhile, it has enriched theoretical predictions for the first ten-order LCDAs ξ-moments. Subsequently, we apply the QCD light-cone sum rules approach to compute the B̅_s^0 → K_0^*(700) transition form factors (TFFs) f_±^B̅_s^0 K_0^*(700)(q^2) and f_T^B̅_s^0 K_0^*(700)(q^2) by taking into account the perturbative 𝒪(α_s) corrections to the twist-2 LCDAs terms. By using the simplified series expansion parameterization, these TFFs are extrapolated over the full physical region. Then, we calculate the differential decay widths and branching fractions for four-body semileptonic decay B̅_s^0 → K^0π^+ ℓ^-ν̅_ℓ with ℓ= (e, μ, τ) via the S-wave K_0^*(700) resonance, respectively. We expect that the obtained prediction results will provide valuable insights for future experiments and theoretical research.
ER  -