arXiv subjects

Hai-Bing Fu

Publications and source records attributed to Hai-Bing Fu.

At least 37 records · Page 2Linked to original sources

arXiv2025

Footprint in fitting $B \to D$ vector form factor and determination for $D$-meson leading-twist LCDA

In this paper, we fit the $B\to D$ vector transition form factor (TFF) by using the data measured by \textsl{BABAR} and Belle Collaborations within Monte Carlo (MC) method. Meanwhile, the $B\to D$ TFF is also calculated by using the QCD light-cone sum rules approach (LCSRs) within right-handed chiral current correlation function. In the TFF, $D$-meson leading-twist light-cone distribution amplitude (LCDA) is the most important non-perturbative input parameter, the precise behavior of which is mainly determined by the parameter $B_{2;D}$ in the light-cone harmonic oscillator model. Through fitting the TFF, we determine the value $B_{2;D}=0.445$. Then, we present the curve of $D$-meson leading-twist LCDA in comparison with other theoretical approaches. Subsequently, the $B\to D$ TFF $f_{+}^{BD}(q^2)$ at the large recoil region is $f_{+}^{BD}(0)=0.648_{-0.063}^{+0.067}$, which is compared in detail with theoretical estimates and experimental measurements. Furthermore, we calculated the decay width and branching fractions of the Cabibbo-favored semileptonic decays $B\to D\ell^+ν_{\ell}$, which lead to the results $\mathcal{B}(B^0\to D^-\ell ^+ν_{\ell}) =(2.10_{-0.38}^{+0.44})\times 10^{-2}$ and $\mathcal{B}(B^+\to \bar{D}^0\ell ^+ν_{\ell}) =(2.26_{-0.41}^{+0.48})\times 10^{-2}$. Finally, we predict the CKM matrix element with two scenarios $|V_{cb}|_{\rm SR}=41.55_{-4.50}^{+4.91}\times 10^{-3}$ and $|V_{cb} |_{\rm MC}=41.47_{-2.66}^{+2.55 }\times 10^{-3}$ from $B^0\to D^-\ell^+ν_{\ell}$, $|V_{cb}|_{\rm SR}=40.54_{-3.80}^{+4.33}\times 10^{-3}$ and $|V_{cb} |_{\rm MC}=40.46_{-1.38}^{+1.40}\times 10^{-3}$ from $B^+\to \bar{D}^0\ell^+ν_{\ell}$ which are in good agreement with theoretical and experimental predictions.

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arXiv2025

Longitudinal leading-twist distribution amplitude of the $^1P_1$-state $b_1(1235)$ meson and its implications on $B\to b_1(1235)\ell^+ν_\ell$ decays

In the paper, we derive the $ξ$-moments $\langleξ_{2;b_1}^{n;\|}\rangle$ of the longitudinal leading-twist distribution amplitude $ϕ_{2;b_1}^{\|}$ for $^1P_1$-state $b_1(1235)$-meson by using the QCD sum rules under the background field theory. Considering the contributions from the vacuum condensates up to dimension-six, its first two non-zero $ξ$-moments at the scale 1 GeV are $\langleξ_{2;b_1}^{1;\|}\rangle= -0.647^{+0.118}_{-0.113}$ and $\langleξ_{2;b_1}^{3;\|}\rangle = -0.328^{+0.055}_{-0.052}$, respectively. Using those moments, we then fix the Gegenbauer expansion series of $ϕ_{2;b_1}^{\|}$ and apply it to calculate $B\to b_1(1235)$ transition form factors (TFFs) that are derived by using the QCD light-cone sum rules. Those TFFs are then extrapolated to the physically allowable $q^2$-range via the simplified series expansion. As for the branching fractions, we obtain ${\cal B}(\bar B^0 \to b_1^+(1235)e^- \barν_e) = 2.179^{+0.553}_{-0.422}\times 10^{-4}$, ${\cal B}(B^0 \to b_1^-(1235)μ^+ν_μ) = 2.166^{+0.544}_{-0.415}\times 10^{-4}$, ${\cal B}(B^+ \to b_1^0(1235)e^+ν_e) = 2.353^{+0.597}_{-0.456}\times 10^{-4}$, and ${\cal B}(B^+ \to b_1^0(1235)μ^+ν_μ) = 2.339^{+0.587}_{-0.448}\times 10^{-4}$, respectively.

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arXiv2025

Probing $D_s^*$-meson longitudinal twist-2 LCDA

In this paper, we carry on an investigation of the semileptonic decays $B_s\to D_s^*\ell \barν_{\ell}$. Firstly, we derive the moments of the $D_s^*$-meson longitudinal leading-twist light-cone distribution amplitude (LCDA) based on QCD sum rules within background field theory framework. Considering the contributions of the vacuum condensates up to dimension-six, its first ten non-zero $ξ$-moments are given. Meanwhile, we construct the $D_s^*$-meson longitudinal leading-twist LCDA by using the light-cone harmonic oscillator model. Then, using those moments, we fix the model parameters $α_{2;D_s^*}$ and $B_1^{2;D_s^*}$ by the least square method and apply them to calculate $B_s \to D_s^*$ transition form factors $A_1(q^2), A_2(q^2)$ and $V(q^2)$ that are derived by using the QCD light-cone sum rules. At the large recoil region, we obtain $A_1(0) =0.632_{-0.135}^{+0.228}, A_2(0) =0.706_{-0.092}^{+0.109}$ and $V(0) =0.647_{-0.069}^{+0.076}$. Those form factors are then extrapolated to the allowed whole physical $q^2$-region through the simplified series expansion. Finally, we obtain the branching fractions for the two decay channels $B_s\to D_s^*\ell\barν_\ell$, $\it i.e.$ ${\cal B}(B_s^0 \to D_s^{*+}e^-\barν_e)=(5.45_{-1.57}^{+2.15})\times 10^{-2}$, ${\cal B}(B_s^0 \to D_s^{*+}μ^-\barν_μ)=(5.43_{-1.57}^{+2.14})\times 10^{-2}$.

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arXiv2025

A phenomenological estimate of rescattering effects in $B_s\to K^{0}\bar{K}^{0}$

The measurements in $b\to s$ penguin-dominated decays are widely recognized as a powerful test for searching for New Physics by studying the deviation from theoretical estimations within the Standard Model. We examine the final-state rescattering effects on the decay $B_s\to K^{*0}\bar{K}^{*0}$ and provide estimations of the branching ratio and longitudinal polarization of $B_s\to K^{*0}\bar{K}^{*0}$, which is consistent with experimental observations. Our conclusion is that both short- and long-distance interactions contribute significantly in this decay. The small longitudinal polarization in $B\to VV$ modes may not be a signal for New Physics.

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arXiv2025

Probing $|V_{cs}|$ and lepton flavor universality through $D\to K_0^\ast(1430)\ellν_{\ell}$ decay

In this paper, we calculate the semileptonic decays $D\to K_0^\ast(1430)\ellν_{\ell}$ with $\ell=(e,μ)$ induced by $c\to s\ellν_{\ell}$ transition. For the key component, $D\to K_0^\ast(1430)$ transition form factors (TFFs) $f_{\pm}(q^2)$ are calculated within the framework of QCD light cone sum rule. Then, we consider two scenarios for $K_0^\ast(1430)$-meson twist-2 distribution amplitude. For the scenario 1 (S1), we take the truncated form based on Gegenbauer polynomial series. Meanwhile, we also consider the scenario 2 (S2) constructed by light cone harmonic oscillator model, where the model parameters are fixed by the $K_0^\ast(1430)$-meson twist-2 distribution amplitude tenth-order $ξ$ moments calculated by using the background field theory. For the TFFs at a large recoil point, we have $f_+^{\rm (S1)}(0)=0.597^{+0.122}_{-0.121}$ and $f_-^{\rm (S1)}(0)=-0.136^{+0.023}_{-0.035}$, $f_+^{\rm (S2)}(0)= 0.663^{+0.135}_{-0.134}$, and $f_-^{\rm (S2)}(0)=-0.202^{+0.026}_{-0.046}$. After extrapolating TFFs to the whole physical $q^2$ region, we calculate the branching fractions of $D^0\to K_0^{\ast +}(1430)\ell^-\barν_\ell$ and $D^+\to K_0^{\ast 0}(1430)\ell^+ν_\ell$, which at $10^{-4}$-order level for the S1 and S2 cases. Meanwhile, we predict the CKM matrix $|V_{cs}|^{\rm (S1)}=0.973^{+0.259}_{-0.183}, |V_{cs}|^{\rm (S2)}=0.880^{+0.234}_{-0.165}$, and lepton flavor universality $\mathcal{R}^{\rm (S1)}_{K_0^*}=0.768^{+0.560}_{-0.368}, \mathcal{R}_{K_0^*}^{\rm (S2)}=0.764^{+0.555}_{-0.365}$. Finally, we discuss the angular observables of forward-backward asymmetries, lepton polarization asymmetries, and $q^2$-differential flat terms for this decay.

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arXiv2024

The rare decay $B^+ \to K^+\ell^+\ell^-(ν\barν)$ under the QCD sum rules approach

In the paper, we conduct a detailed investigation of the rare decay processes of charged meson, specifically $B^+ \to K^+\ell^+\ell^-$ with $\ell=(e,μ,τ)$ and $B^+ \to K^+ν\barν$. These processes involve flavor-changing-neutral-current (FCNC) transitions, namely $b\to s\ell^+\ell^-$ and $b\to sν\barν$. The essential components $B\to K$ scalar, vector and tensor transition form factors (TFFs) are calculated by using the QCD light-cone sum rules approach up to next-to-leading order QCD corrections. In which, the kaon twist-2 and twist-3 light-cone distribution amplitudes are calculated from both the QCD sum rules within the framework of background field theory and the light-cone harmonic oscillator model. The TFFs at large recoil point are $f_+^{BK}(0)=f_0^{BK}(0) =0.328_{-0.028}^{+0.032}$ and $f_{\rm T}^{BK}(0)=0.277_{-0.024}^{+0.028}$, respectively. To achieve the behavior of those TFFs in the whole $q^2$-region, we extrapolate them by utilizing the simplified $z(q^2)$-series expansion. Furthermore, we compute the differential branching fractions with respect to the squared dilepton invariant mass for the two different decay channels and present the corresponding curves. Our predictions of total branching fraction are ${\cal B}(B^+\to K^+ e^+ e^-)=6.633_{-1.070}^{+1.341}\times 10^{-7}$, ${\cal B}(B^+\to K^+ μ^+ μ^-)=6.620_{-1.056}^{+1.323}\times 10^{-7}$, ${\cal B}(B^+\to K^+ τ^+ τ^-)=1.760_{-0.197}^{+0.241}\times 10^{-7}$, and ${\cal B}(B^+\to K^+ ν\barν)=4.135_{-0.655}^{+0.820}\times 10^{-6}$, respectively. Lastly, the observables such as the lepton universality $\mathcal{R}_{K}$ and the angular distribution `flat term' $F_{\rm H}^\ell$ are given, which show good agreement with the theoretical and experimental predictions.

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arXiv2024

Prospective analysis of CKM element $|V_{cd}|$ and $D^+$-meson decay constant from leptonic decays $D^+ \to \ell^+ ν$

The leptonic decay of $D^+$-meson has attracted significant interest due to its unique characteristics. In this paper, we carry out an investigation into the $D^+$-meson leptonic decays $D^+\to \ell^+ν_{\ell}$ with $\ell=(e,μ,τ)$ by employing the QCD sum rules approach. In which the $D^+$-meson decay constant $f_{D^+}$ is an important input parameter in the process. To enhance the accuracy of our calculations for $f_{D^+}$, we consider the quark propagator and vertex up to dimension-six within the framework of background field theory. Consequently, we obtain the QCD sum rule expression for $f_{D^+}$ up to dimension-six condensates, yielding $f_{D^+}=203.0\pm1.5~\mathrm{MeV}$. Our results are in good agreement with BESIII measurements and theoretical predictions. We also present the integrated decay widths for the $D^+$-meson in three channels $Γ(D^+\to e^+ν_e)=(5.263_{-0.075}^{+0.076})\times10^{-21}~\mathrm{GeV}$, $Γ(D^+\to μ^+ν_μ)=(2.236_{-0.032}^{+0.032})\times10^{-16}~\mathrm{GeV}$ and $Γ(D^+\to τ^+ν_τ)=(5.958_{-0.085}^{+0.086})\times10^{-16}~\mathrm{GeV}$. Accordingly, we compute the branching fraction $\mathcal{B}(D^+\to\ell^+ν_{\ell})$ with the electron, muon and tau channels, which are $\mathcal{B}(D^+\to e^+ν_e)=(8.260_{-0.118}^{+0.119})\times10^{-9}$, $\mathcal{B}(D^+\toμ^+ν_μ)=(3.508_{-0.050}^{+0.051})\times10^{-4}$ and $\mathcal{B}(D^+\toτ^+ν_τ)=(0.935_{-0.013}^{+0.013})\times10^{-3}$. Furthermore, we present our prediction for the CKM matrix element $|V_{cd}|$ using the branching fraction $\mathcal{B}(D^+\toμ^+ν_μ)$ obtained from BESIII Collaboration, yielding $|V_{cd}|=0.227_{-0.001}^{+0.002}$.

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arXiv2024

Scrutinizing $B^0$-meson flavor changing neutral current decay into scalar $K_0^*(1430)$ meson with $b\to s \ell^+\ell^-(ν\barν)$ transition

In this paper, we investigate the rare decay $B^0\to K_0^*(1430)\ell^+\ell^-$ with $\ell=(e,μ,τ)$ and $B^0\to K_0^*(1430)ν\barν$ induced by the flavor changing neutral current transition of $b\to s\ell^+\ell^-(ν\barν)$. Firstly, the $B^0\to K_0^*(1430)$ transition form factors (TFFs) are calculated by using the QCD light-cone sum rule approach up to next-to-leading order accuracy. In which the $K_0^*(1430)$-meson twist-2 and twist-3 LCDAs have been calculated both from the SVZ sum rule in the background field theory framework and light-cone harmonic oscillator model. Then, we obtained the three TFFs at large recoil point, {\it i.e.,} $f_+^{B^0\to K_0^\ast}(0)= 0.470_{-0.101}^{+0.086}$, $f_-^{B^0\to K_0^\ast}(0)= -0.340_{-0.068}^{+0.068}$, and $f_{\rm T}^{B^0\to K_0^\ast}(0)= 0.537^{+0.112}_{-0.115}$. Meanwhile, we extrapolated TFFs to the whole physical $q^2$-region by using the simplified $z(q^2)$-series expansion. Furthermore, we calculate the $B^0\to K_0^*(1430)\ell^+\ell^-(ν\barν)$ decay widths, branching fractions, and longitudinal lepton polarization asymmetries of $B^0\to K_0^*(1430)\ell^+\ell^-$, which lead to ${\cal B}(B^0\to K_0^*(1430)e^+e^-) = (6.65^{+2.52}_{-2.42})\times 10^{-7}$, ${\cal B}(B^0\to K_0^*(1430)μ^+μ^-)=(6.62^{+2.51}_{-2.41})\times 10^{-7}$, ${\cal B}(B^0\to K_0^*(1430)τ^+τ^-)=(1.88^{+1.10}_{-0.97})\times 10^{-8}$, ${\cal B}(B^0\to K_0^*(1430)ν\barν)= 3.85^{+1.55}_{-1.48}\times 10^{-6}$ and the integrated longitudinal lepton polarization asymmetries $\langle A_{P_L} \rangle = (-0.99, -0.96, -0.03)$ for the cases $\ell=(e, μ, τ)$ respectively.

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arXiv2024

Quasi-two-body decays $B\to P f_0(500)\to Pπ^+π^-$ in the perturbative QCD approach

In this paper, we study the quasi-two-body decays $B\to P f_0(500)\to Pπ^+π^-$ [with $P=(π, K, η, η^{\prime})$] within framework of perturbative QCD (PQCD) factorization approach. With the help of $π$-$π$ distribution amplitude and scalar form factor $F_{ππ}(ω^2)$, we calculate the $CP$ averaged branching fraction and the $CP$ asymmetry for the quasi-two-body decays $B\to P f_0(500)\to Pπ^+π^-$. Taking the quasi-two-body decay $B^+ \to π^+ f_0(500) \to π^+ π^+ π^-$ as an explicit example, we present the behavior of differential branching fraction and direct $CP$ violation versus the $π$-$π$ invariant mass. The total branching fraction and direct $CP$ violation are $\mathcal{B}(B^+\to π^+ [σ\to]π^+π^-) = (1.78 \pm 0.41\pm 0.51) \times 10^{-6}$ and $\mathcal{A}_{CP}(B^+\to π^+ [σ\to]π^+π^-) = (29.8\pm 11.1\pm 13.0)\%$ respectively. Our results could be tested by further experiments.

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arXiv2024

Searching for $|V_{cd}|$ through the exclusive decay $D_s^+ \to K^0e^+ν_e$ within QCD Sum Rules

In this paper, we carry out an investigation into the semileptonic decays $D_s^+ \to K^0\ell^+ν_\ell$ with $\ell=(e,μ)$ by employing the QCD light-cone sum rules approach. The vector transition form factor (TFF) $f_+^{D_s^+ K^0}(q^2)$ for $D_s^+\to K^0$ decay is calculated while considering its next-to-leading order contribution. Subsequently, we briefly introduce the twist-2, 3 kaon distribution amplitudes, which are calculated by using QCD sum rules within the framework of the background field theory. At the large recoil point, the TFF has $f_+^{D_s^+ K^0}(0)=0.692_{-0.026}^{+0.027}$. Then, we extrapolate $f_+^{D_s^+ K^0}(q^2)$ to the whole physical $q^2$-region via the simplified $z(q^2,t)$-series expansion, and the behavior of TFF $f_+^{D_s^+ K^0}(q^2)$ is exhibited in the numerical results part, including the theoretical and experimental predictions for comparison. In addition, we compute the differential branching fraction $\mathcal{B}(D_s^+ \to K^0\ell^+ν_\ell)$ with the electron and muon channels, which are expected to be $\mathcal{B}(D_s^+ \to K^0e^+ν_e)=3.379_{-0.275}^{+0.301}\times 10^{-3}$ and $\mathcal{B}(D_s^+ \to K^0μ^+ν_μ)=3.351_{-0.273}^{+0.299}\times 10^{-3}$ as well as contained other results for comparison. Our results show good agreement with the BESIII measurements and theoretical predictions. Furthermore, we present our prediction with respect to the CKM matrix element $|V_{cd}|$ by using the $\mathcal{B}(D_s^+ \to K^0e^+ν_e)$ result from BESIII Collaboration, yielding $|V_{cd}|=0.221_{-0.010}^{+0.008}$. Finally, we provide the ratio between $D_s^+ \to K^0e^+ν_e$ and $D_s^+ \to ηe^+ν_e$ channels, i.e. $\mathcal{R}_{K^0/η}^e=0.144_{-0.020}^{+0.028}$.

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arXiv2024

An improved light-cone harmonic oscillator model for the $ϕ$-meson longitudinal leading-twist light-cone distribution amplitude

In the present paper, we study the properties of $ϕ$-meson longitudinal leading-twist light-cone distribution amplitude $ϕ_{2;ϕ}^{\|}(x,μ)$ by starting from a light-cone harmonic oscillator model for its wavefunction. To fix the input parameters, we derive the first ten $ξ$-moments of $ϕ_{2;ϕ}^{\|}(x,μ)$ by using the QCD sum rules approach under the background field theory. The shape of $ϕ_{2;ϕ}^{\|}(x,μ=2~{\rm GeV})$ tends to be a single-peak behavior, which is consistent with the latest Lattice QCD result. As an application, we derive the $D^+_s \to ϕ$ transition form factors (TFFs) by using the light-cone sum rules approach. At the large recoil point, we obtain $A_1(0) = 0.512_{-0.020}^{+0.030}$, $A_2(0) = 0.402_{-0.067}^{+0.078}$, $A_0(0) = 0.596_{-0.020}^{+0.025}$ and $V(0) = 0.882_{-0.036}^{+0.040}$. As for the two typical ratios $γ_V$ and $γ_2$, we obtain $γ_V = 1.723_{-0.021}^{+0.023}$ and $γ_2 = 0.785_{-0.104}^{+0.100}$. After extrapolating those TFFs to the physically allowable region, we then obtain the transverse, longitudinal and total decay widths for semi-leptonic decay $D^+_s\toϕ\ell^+ν_{\ell}$. Then the branching fractions are ${\cal B}(D^+_s\to ϕe^+ν_e) = (2.367_{-0.132}^{+0.256})\times 10^{-3}$ and ${\cal B}(D^+_s\to ϕμ^+ν_μ) = (2.349_{-0.132}^{+0.255})\times 10^{-3}$, which show good agreement with the data issued by the BESIII, the CLEO, and the BABAR Collaborations. We finally calculate $D^+_s\toϕ\ell^+ ν_\ell$ polarization and asymmetry parameters.

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arXiv2024

Investigation for $D^+ \to π^+ ν\barν$ decay process within QCDSR approach

In the paper, we investigate the charmed meson rare decay process $D^+ \to π^+ν\barν$ by using QCD sum rules approach. Firstly, the pion twist-2 and twist-3 distribution amplitude $ξ$-moments $\langleξ_{2;π}^n\rangle|_μ$ up to 10th-order and $\langle ξ_{3;π}^{(p,σ),n}\rangle|_μ$ up to fourth-order are calculated by using QCD sum rule under background field theory. After constructing the light-cone harmonic oscillator model for pion twist-2, 3 DAs, we get their behaviors by matching the calculated $ξ$-moments. Then, the $D\to π$ transition form factors are calculated by using QCD light-cone sum rules approach. The vector form factor at large recoil region is $f_+^{D\toπ}(0) = 0.627^{+0.120} _{-0.080}$. By taking the rapidly $z(q^2,t)$ converging simplified series expansion, we present the TFFs and the corresponding angular coefficients in the whole squared momentum transfer physical region. Furthermore, we display the semileptonic decay process $\bar D^0 \to π^+ e\bar ν_e$ differential decay widths and branching fraction with ${\cal B}(\bar D^0\toπ^+e\barν_e) = 0.308^{+0.155}_{-0.066} \times 10^{2}$. The $\bar D^0\toπ^+e\barν_e$ differential/total predictions for forward-backward asymmetry, $q^2$-differential flat terms and lepton polarization asymmetry are also given. After considering the non-standard neutrino interactions, the predictions for the $D^+ \to π^+ ν\barν$ branching fraction is ${\cal B}(D^+ \to π^+ {ν}{\barν}) = 1.85^{+0.93}_{-0.46}\times10^{-8}$.

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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 $B(D)^+ \toη^{(\prime)}\ell^+ ν_\ell$.

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arXiv2023

Further study on the production of P-wave doubly heavy baryons from Z-boson decays

In this paper, we carried out a systematic investigation for the excited doubly heavy baryons production in $Z$-boson decays within the NRQCD factorization approach. Our investigation accounts for all the $P$-wave intermediate diquark states, {\it i.e.} $\langle cc\rangle[^1P_1]_{\bar 3}$, $\langle cc\rangle[^3P_J]_{6}$, $\langle bc\rangle[^1P_1]_{\bar 3/6}$, $\langle bc\rangle[^3P_J]_{\bar 3/6}$, $\langle bb\rangle[^1P_1]_{\bar 3}$, and $\langle bb\rangle[^3P_J]_{6}$ with $J = (0, 1, 2)$. The results show that contributions from all diquark states in $P$-wave were $7\%$, $8\%$, and $3\%$ in comparing with $S$-wave for the production of $Ξ_{cc}$, $Ξ_{bc}$ and $Ξ_{bb}$ via $Z$-boson decay, respectively. Based on these results, we predicted about $0.539\times 10^3(10^6)$ events for $Ξ_{cc}$, $1.827\times 10^3(10^6)$ events for $Ξ_{bc}$, and $0.036\times 10^3(10^6)$ events for $Ξ_{bb}$ can be produced annually at the LHC (CEPC). Additionally, we plot the differential decay widths of $Ξ_{cc}$, $Ξ_{bc}$ and $Ξ_{bb}$ as a function of the invariant mass $s_{23}$ and energy function $z$ distributions, and analyze the theoretical uncertainties in decay width arising from the mass parameters of heavy quark.

hep-ph↗

arXiv2023

Investigating $D_s^+ \to π^0 \ell^+ ν_\ell$ decay process within QCD sum rule approach

In this paper, the semileptonic decays $D_s^+ \to π^0\ell^+ ν_\ell$ with $\ell=(e,μ)$ are investigated by using the light-cone sum rule approach. Firstly, the neutral meson mixing scheme between $π^0$, $η$, $η^\prime$ and pseudoscalar gluonium $G$ is discussed in a unified way, which leads to the direct connection between two different channels for $D_s^+\to π^0\ell^+ν_\ell$ and $D_s^+ \to η\ell^+ν_\ell$ by the $π^0-η$ mixing angle. Then we calculated the $D_s\to π^0$ transition form factors (TFFs) within QCD light-cone sum rule approach up to next-to-leading order correction. At the large recoil point, we have $f_+^{D_s^+π^0}(0)=0.0113_{-0.0019}^{+0.0024}$ and $f_-^{D_s^+π^0}(0)=0.0020_{-0.0009}^{+0.0008}$. Furthermore, the TFFs are extrapolated to the whole physical $q^2$-region by using the simplified $z(q^2)$-series expansion. The behaviors of TFFs and related three angular coefficient functions $a_{θ_\ell}(q^2)$, $b_{θ_\ell}(q^2)$ and $c_{θ_\ell}(q^2)$ are given. The differential decay widths for $D_s^+ \to π^0\ell^+ ν_\ell$ with respect to $q^2$ and $\cosθ_\ell$ are presented, and also lead to the branching fractions ${\cal B}(D_s^+\to π^0e^+ν_e) =2.60_{-0.51}^{+0.57}\times 10^{-5}$ and ${\cal B}(D_s^+\to π^0μ^+ν_μ)= 2.58_{-0.51}^{+0.56}\times 10^{-5}$. These results show well agreement with the recent BESIII measurements and theoretical predictions. Then the differential distributions and integrated predictions for three angular observables, {\it i.e.} forward-backward asymmetries, $q^2$-differential flat terms and lepton polarization asymmetries are given separately. Lastly, we estimate the ratio for different decay channels ${\cal R}_{π^0/η}^{\ell}=1.108_{-0.071}^{+0.039}\times 10^{-3}$.

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arXiv2023

$ρ$-meson longitudinal leading-twist distribution amplitude revisited and the $D\to ρ$ semileptonic decay

Motivated by our previous work [Phys. Rev. D \textbf{104}, no.1, 016021 (2021)] on pionic leading-twist distribution amplitude (DA), we revisit $ρ$-meson leading-twist longitudinal DA $ϕ_{2;ρ}^\|(x,μ)$ in this paper. A model proposed by Chang based on the Dyson-Schwinger equations (DSEs) is adopted to describe the behavior of $ϕ_{2;ρ}^\|(x,μ)$. On the other hand, the $ξ$-moments of $ϕ_{2;ρ}^\|(x,μ)$ are calculated with the QCD sum rules in the framework of the background field theory. The sum rule formula for those moments are improved. More accurate values for the first five nonzero $ξ$-moments at typical scale $μ=1, 1.4, 2, 3~{\rm GeV}$ are given, e.g., at $μ= 1~{\rm GeV}$, \modi{$\langleξ^2\rangle_{2;ρ}^\| = 0.220(6) $, $\langleξ^4\rangle_{2;ρ}^\| = 0.103(4)$, $\langleξ^6\rangle_{2;ρ}^\| = 0.066(5)$, $\langleξ^8\rangle_{2;ρ}^\| = 0.046(4)$ and $\langleξ^{10}\rangle_{2;ρ}^\| = 0.035(3)$}. By fitting those values with the least squares method, the DSE model for $ϕ_{2;ρ}^\|(x,μ)$ is determined. By taking the left-handed current light-cone sum rule approach, we get the transition form factor at large recoil region, {\it i.e.} $A_1(0) = 0.498^{+0.014}_{-0.012}$, $A_2(0)=0.460^{+0.055}_{-0.047}$, $V(0) = 0.800^{+0.015}_{-0.014}$, and the ratio $r_2 = 0.923^{+0.133}_{-0.119}$, $r_V = 1.607^{+0.071}_{-0.071}$. After making the extrapolation with a rapidly converging series based on $z(t)$-expansion, we present the decay width for the semileptonic decays $D\toρ\ell^+ν_\ell$. Finally, the branching fractions are $\mathcal{B}(D^0\to ρ^- e^+ ν_e) = 1.889^{+0.176}_{-0.170}\pm 0.005$, $\mathcal{B}(D^+ \to ρ^0 e^+ ν_e) = 2.380^{+0.221}_{-0.214}\pm 0.012$, $\mathcal{B}(D^0\to ρ^- μ^+ ν_μ) = 1.881^{+0.174}_{-0.168}\pm 0.005$, $\mathcal{B}(D^+ \to ρ^0 μ^+ ν_μ) =2.369^{+0.219}_{-0.211}\pm 0.011$.

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↗