Quasi-four-body semileptonic decay $\bar B^0\to a_0(1450)^+ (\toπ^+ η)\ell^-\barν_\ell$ within $a_0(1450)$-resonance leading-twist LCDA under QCDSR
Year: 2026
Type: preprint
Abstract: The finite width of broad scalar resonances should be taken into account when relating semileptonic $B$-meson transitions to experimentally reconstructable multihadron final states. The quasi-four-body semileptonic decays $\bar B^0\to a_0(1450)^+ (\toπη)\ell^-\barν_\ell$ with $\ell=(e,μ,τ)$ provide a platform for investigating the scalar $a_0(1450)^+$-resonance as the lowest-Fock-state quark-antiquark component. We calculate the first five odd $ξ$-moments of $a_0(1450)$-resonance twist-2 light-cone distribution amplitude (LCDA) using QCDSR within the background-field theory, including vacuum condensates up to dimension six. Based on these moments, two twist-2 LCDA schemes are constructed: a light-cone harmonic oscillator model (S1), whose free parameters are fitted to the first five odd moments, and a truncated Gegenbauer expansion (S2) retaining only $a_{1,3}(μ)$. The $\bar{B}^0 \to a_0(1450)^+$ transition form factors are then calculated using light-cone sum rules. At large recoil region, we present the TFFs with different scheme. The finite-width effect of $a_0(1450)$-resonance is further incorporated through a two-channel Flatté parametrization including the $πη$ and $K\bar{K}$ channels. The $πη$ invariant-mass distribution exhibits a pronounced resonance peak around $s\simeq m_{a_0(1450)}^2$. The spectra of the electron and muon channels are nearly identical, while the $τ$-channel is significantly suppressed because the larger lepton mass reduces the available phase space. After integration over the full quasi-four-body phase space, the branching fractions are given. We expect that these results will provide useful guidance for future experimental and theoretical studies of $\bar B^0\to a_0(1450)^+ (\toπη)\ell^-\barν_\ell$ decay and help improve our understanding of the internal structure of $a_0(1450)$.
Source: arXiv (Cornell University)
Institutions: Guizhou Minzu University, Chongqing University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2588925934, G4938763488
OpenAlex ID: W7164894477