arXiv subjects

Zai-Hui Wu

Publications and source records attributed to Zai-Hui Wu.

5 recordsLinked to original sources

arXiv2023

Properties of the $η_q$ leading-twist distribution amplitude and its effects to the $B/D^+ \toη^{(\prime)}\ell^+ ν_\ell$ decays

The $η^{(\prime)}$-mesons in the quark-flavor basis are mixtures of two mesonic states $|η_{q}\rangle=|\bar u u+\bar d d\rangle/\sqrt 2$ and $|η_{s}\rangle=|\bar s s\rangle$. In the previous work, we have made a detailed study on the $η_{s}$ leading-twist distribution amplitude. As a sequential work, in the present paper, we fix the $η_q$ leading-twist distribution amplitude by using the light-cone harmonic oscillator model for its wave function and by using the QCD sum rules within the QCD background field to calculate its moments. The input parameters of $η_q$ leading-twist distribution amplitude $ϕ_{2;η_q}$ at an initial scale $μ_0\sim 1$ GeV are then fixed by using those moments. The sum rules for the $0_{\rm th}$-order moment can also be used to fix the magnitude of $η_q$ decay constant, which gives $f_{η_q}=0.141\pm0.005$ GeV. As an application of the present derived $ϕ_{2;η_q}$, we calculate the transition form factors $B(D)^+ \toη^{(\prime)}$ by using the QCD light-cone sum rules up to twist-4 accuracy and by including the next-to-leading order QCD corrections to the twist-2 part, and then fix the related CKM matrix element and the decay width for the semi-leptonic decays $B(D)^+ \toη^{(\prime)}\ell^+ ν_\ell$.

hep-ph↗

arXiv2023

$K_0^\ast(1430)$ Twist-2 Distribution Amplitude and $B_s,D_s \to K_0^\ast(1430)$ Transition Form Factors

Based on the scenario that the $K_0^\ast(1430)$ is viewed as the ground state of $s\bar{q}$ or $q\bar{s}$, we study the $K_0^\ast(1430)$ leading-twist distribution amplitude (DA) $ϕ_{2;K_0^\ast}(x,μ)$ with the QCD sum rules in the framework of background field theory. A more reasonable sum rule formula for $ξ$-moments $\langleξ^n\rangle_{2;K_0^\ast}$ is suggested, which eliminates the influence brought by the fact that the sum rule of $\langleξ^0_p\rangle_{3;K_0^\ast}$ cannot be normalized in whole Borel region. More accurate values of the first ten $ξ$-moments, $\langleξ^n\rangle_{2;K_0^\ast} (n = 1,2,\cdots,10)$, are evaluated. A new light-cone harmonic oscillator (LCHO) model for $K_0^\ast(1430)$ leading-twist DA is established for the first times. By fitting the resulted values of $\langleξ^n\rangle_{2;K_0^\ast} (n = 1,2,\cdots,10)$ via the least squares method, the behavior of $K_0^\ast(1430)$ leading-twist DA described with LCHO model is determined. Further, by adopting the light-cone QCD sum rules, we calculate the $B_s,D_s \to K_0^\ast(1430)$ transition form factors and branching fractions of the semileptonic decays $B_s,D_s \to K_0^\ast(1430) \ell ν_\ell$. The corresponding numerical results can be used to extract the Cabibbo-Kobayashi-Maskawa matrix elements by combining the relative experimental data in the future.

hep-ph↗

arXiv2023

$a_0(980)$-meson twist-2 distribution amplitude within the QCD sum rules and investigation of $D \to a_0(980) (\toηπ) e^+ν_e$

In this paper, moments of $a_0(980)$-meson twist-2 light-cone distribution amplitudes were deeply researched by using QCD sum rules approach within background field theory. Up to 9th-order accuracy, we present $\langleξ_{2;a_0}^n\rangle|_{μ_0}$ at the initial scale $μ_0 = 1~{\rm GeV}$, i.e. $\langleξ^1_{2;a_0}\rangle|_{μ_0} = -0.307(43)$, $\langleξ^3_{2;a_0}\rangle|_{μ_0} = -0.181(34)$, $\langleξ^5_{2;a_0}\rangle|_{μ_0} = -0.078(28)$, $\langleξ^7_{2;a_0}\rangle|_{μ_0} = -0.049(26)$, $\langleξ^9_{2;a_0}\rangle|_{μ_0} = -0.036(24)$, respectively. An improved light-cone harmonic oscillator model for $a_0(980)$-meson twist-2 light-cone distribution amplitudes is adopted, where its parameters are fixed by using the least squares method based on the $\langleξ_{2;a_0}^n\rangle|_{μ_0}$, and their goodness of fit reach to $95.4\%$. Then, we calculate the $D\to a_0(980)$ transition form factors within the light-cone sum rules approach, and at largest recoil point, we obtain $f_+^{D\to a_0}(0) = 1.058^{+0.068}_{-0.035}$ and $f_-^{D\to a_0}(0) = 0.764^{+0.044}_{-0.036}$. As a further application, the branching fractions of the $D\to a_0(980)\ell\barν_\ell$ semileptonic decays are given. Taking the decay $a_0(980)\to ηπ$ into consideration, we obtain ${\cal B}(D^0 \to a_0(980)^- (\to ηπ^-) e^+ν_e) =(1.330^{+0.216}_{-0.134})\times10^{-4}$, ${\cal B}(D^+\to a_0(980)^0(\to ηπ^0)e^+ν_e)=(1.675^{+0.272}_{-0.169})\times10^{-4}$, which are consistent with the BESIII collaboration and PDG data within errors. Finally, we present the angle observables of forward-backward asymmetries, $q^2$-differential flat terms and lepton polarization asymmetry of the semileptonic decay $D\to a_0(980)\ell\barν_\ell$.

hep-ph↗

arXiv2022

Searching for $a_0(980)$-meson parton distribution function

In this paper, we calculate the scalar $a_0(980)$-meson leading-twist wavefunction by using light-cone harmonic oscillator model (LCHO). In which the model parameters are determined by fitting the $ξ$-moments $\langleξ_{a_0}^n\rangle_ζ$ of its light-cone distribution amplitudes. Then, the $a_0(980)$-meson leading-twist light-cone distribution amplitudes with three different scales $ζ= (1.0, 2.0, 5.2)~{\rm GeV}$ are given. After constructing the relationship between $a_0(980)$-meson leading-twist parton distribution functions/valence quark distribution function and its LCHO wavefunction, we exhibit the $q^{a_0}(x,ζ)$ and $x q^{a_0}(x,ζ)$ with different scales. Furthermore, we also calculate the Mellin moments of the $a_0(980)$-meson's valence quark distribution function $\langle x^n q^{a_0}\rangle_ζ$ with $n = (1,2,3)$, i.e. $\langle x q^{a_0}\rangle_{ζ_5} = 0.026$, $\langle x^2 q^{a_0}\rangle_{ζ_5} = 0.017$ and $\langle x^3 q^{a_0}\rangle_{ζ_5} = 0.012$. Finally, the scale evolution for the ratio of the Mellin moments $x^n_{a_0}(ζ,ζ_k)$ are presented.

hep-ph↗

arXiv2022

$a_1(1260)$-meson longitudinal twist-2 distribution amplitude and the $D\to a_1(1260)\ell^+ν_\ell$ decay processes

In the paper, we investigate the moments $\langleξ_{2;a_1}^{\|;n}\rangle$ of the axial-vector $a_1(1260)$-meson distribution amplitude by using the QCD sum rules approach under the background field theory. By considering the vacuum condensates up to dimension-six and the perturbative part up to next-to-leading order QCD corrections, its first five moments at an initial scale $μ_0=1~{\rm GeV}$ are $\langleξ_{2;a_1}^{\|;2}\rangle|_{μ_0} = 0.223 \pm 0.029$, $\langleξ_{2;a_1}^{\|;4}\rangle|_{μ_0} = 0.098 \pm 0.008$, $\langleξ_{2;a_1}^{\|;6}\rangle|_{μ_0} = 0.056 \pm 0.006$, $\langleξ_{2;a_1}^{\|;8}\rangle|_{μ_0} = 0.039 \pm 0.004$ and $\langleξ_{2;a_1}^{\|;10}\rangle|_{μ_0} = 0.028 \pm 0.003$, respectively. We then construct a light-cone harmonic oscillator model for $a_1(1260)$-meson longitudinal twist-2 distribution amplitude $ϕ_{2;a_1}^{\|}(x,μ)$, whose model parameters are fitted by using the least squares method. As an application of $ϕ_{2;a_1}^{\|}(x,μ)$, we calculate the transition form factors (TFFs) of $D\to a_1(1260)$ in large and intermediate momentum transfers by using the QCD light-cone sum rules approach. At the largest recoil point ($q^2=0$), we obtain $ A(0) = 0.130_{ - 0.013}^{ + 0.015}$, $V_1(0) = 1.898_{-0.121}^{+0.128}$, $V_2(0) = 0.228_{-0.021}^{ + 0.020}$, and $V_0(0) = 0.217_{ - 0.025}^{ + 0.023}$. By applying the extrapolated TFFs to the semi-leptonic decay $D^{0(+)} \to a_1^{-(0)}(1260)\ell^+ν_\ell$, we obtain ${\cal B}(D^0\to a_1^-(1260) e^+ν_e) = (5.261_{-0.639}^{+0.745}) \times 10^{-5}$, ${\cal B}(D^+\to a_1^0(1260) e^+ν_e) = (6.673_{-0.811}^{+0.947}) \times 10^{-5}$, ${\cal B}(D^0\to a_1^-(1260) μ^+ ν_μ)=(4.732_{-0.590}^{+0.685}) \times 10^{-5}$, ${\cal B}(D^+ \to a_1^0(1260) μ^+ ν_μ)=(6.002_{-0.748}^{+0.796}) \times 10^{-5}$.

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