arXiv subjects

Hai-Jiang Tian

Publications and source records attributed to Hai-Jiang Tian.

12 recordsLinked to original sources

arXiv2026

$a_0(1450)$-state twist-2 light-cone distribution amplitude moments within QCD sum rules and its implication in $\bar B^0\to a_0(1450)^+\ell^-\barν_\ell$ decays

Based on longstanding puzzle for the structure of light scalar meson, it is meaningful to make a deep research for its property in different decay processes especially in the bottom meson semileptonic decays. The current experimental and theoretical predictions are inclined to the quark-antiquark state in $B$-decays, which is also the basic starting point of this work. Firstly, the first five-order $a_0(1450)$-state leading-twist distribution amplitude $ξ$-moments are calculated by using the QCD sum rule within background field theory, which all the gluon-condensate and quark-condensate are calculated up to full dimension-six accuracy. We present the their values up to nineth-order at initial scale. Then we construct $a_0(1450)$-state twist-2 LCDA with light-cone harmonic oscillator models as the scenario 1 (S1), where the model parameters are determined by fitting the first five odd $ξ$-moments using the least squares method. On the other hand, the truncated form of Gegenbauer polynomials expansion up to second-order is also considered as the scenario 2 (S2) to make a comparison, where the relationship between Gegenbauer moments and LCDA moments are considered. Subsequently, we calculated the $\bar{B}^0 \to a_0(1450)^+$ transition form factors (TFFs) by using the light-cone sum rules approach, incorporating contributions from both twist-2 and twist-3 LCDAs. By extrapolating TFFs to the entire physical $q^2$-region with simplified series expansion, the differential decay width and branching ratios for the $\bar B^0\to a_0(1450)^+\ell^-\barν_\ell$ semileptonic decay are obtained. Finally, we present three angular observables including forward-backward asymmetry, lepton polarization asymmetry and $q^2$-differential flat term.

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arXiv2026

Probing the equivalence of chiral LCSRs in $D \to πe ν_e$ decays and extraction of $|V_{cd}|$

In the paper, we have carried out research on the $D\toπ$ decay process. We employ two different currents to study the $D\toπ$ transition form factors (TFFs) by using the light-cone sum rule within the framework of chiral current approach. Firstly, we follow the right-handed and left-handed currents for the correlators to present the expression of the vector form factors upto next-leading-order and leading-order accuracy, respectively. Here the twist-2 and twist-3 light-cone distribution amplitudes are constructed by the light-cone harmonic oscillator model. After exploring the TFFs into the whole physical $q^2$-region with the simplified $z$-series expansion, we obtain the branching fractions $\mathcal{B}(D^0\to π^-e^+ν_e)_{\text{I}} = 0.31_{-0.05}^{+0.05}$, $\mathcal{B}(D^+\to π^0e^+ν_e)_{\text{I}} = 0.39_{-0.06}^{+0.06}$, $\mathcal{B}(D^0\to π^-e^+ν_e)_{\text{II}} = 0.27_{-0.03}^{+0.05}$, $\mathcal{B}(D^+\to π^0e^+ν_e)_{\text{II}} = 0.34_{-0.04}^{+0.06}$, and extract the CKM matrix element $|V_{cd}|_{\text{I}} = ( 0.21^{+0.02}_{-0.02} )\times 10^{-2}$ as well as $|V_{cd}|_{\text{II}} = ( 0.23^{+0.02}_{-0.02}) \times 10^{-2}$. To verify the credibility of our calculations, these results are further compared with existing findings in the literature, showing good agreement within uncertainties.

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arXiv2025

Light-cone sum rules analysis of the semi-leptonic $D^+_s\to f_0(980)(\toπ^+π^-)e^+ν_e$ decay incorporating $f_0(980)$ mixing state twist-2 distribution amplitudes

The isospin-singlet scalar meson $f_0(980)$ is hypothesized to consist of two energy eigenstates, forming a mixture of $\frac{1}{\sqrt{2}}(\bar{u}u + \bar{d}d)$ and $\bar{s}s$. Building on this framework, we apply the QCD sum rules approach in the background field theory to compute the $f_0(980)$ decay constant, yielding $f_{f_0}(μ_0=1\,\text{GeV}) = 0.386\pm0.009 \, \text{GeV}$. Subsequently, we derive the first two $ξ$-moments of the leading-twist light-cone distribution amplitude $ϕ_{2;f_0}$. Using QCD light-cone sum rules, we then calculate the $D^+_s \to f_0(980)$ transition form factor (TFF) $f_+(q^2)$, obtaining $f_+(0) = 0.516^{+0.027}_{-0.024}$ at the large-recoil point. We extend $f_+(q^2)$ to the full physical region via a simplified series expansion parameterization, enabling calculations of the differential decay widths and the branching fraction $\mathcal{B}(D^+_s \to f_0(980)(\to π^+π^-)e^+ν_e) = (1.783^{+0.227}_{-0.189}) \times 10^{-3}$. Our theoretical predictions align well with the latest BESIII Collaboration measurements within reasonable errors.

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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

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

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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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.

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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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arXiv2022

Investigation for $Z$-boson decay into $Ξ_{bc}$ and $Ξ_{bb}$ baryon with the NRQCD factorizations approach

The $Z$-boson decay provides good opportunities for the research on $Ξ_{bQ'}$ baryon due to large quantity of $Z$ events that can be collected at the high-energy colliders. We performed a completed investigation of the indirect production of the $Ξ_{bc}$ and $Ξ_{bb}$ baryon via $Z$-boson decay $Z\to Ξ_{bQ'}+\bar b +\bar Q'$ with $Q'= (c, b)$ quark according to NRQCD factorizations approach. After considering the contribution of the diquark states $\langle bc\rangle [^3S_1]_{\bar 3/6}$, $\langle bc\rangle [^1S_0]_{\bar 3/6}$, $\langle bb\rangle [^1S_0]_{6}$ and $\langle bb\rangle [^3S_1]_{\bar 3}$, the calculated branching ratio for $Z\toΞ_{bQ'}+X$ are ${\cal B}(Z\toΞ_{bc}+X) = 3.595\times 10^{-5}$ and ${\cal B}(Z\toΞ_{bc}+X) = 1.213\times 10^{-6}$. Moreover, the $Ξ_{bc}$ events produced are predicted to be of the $10^4(10^7)$ order at the LHC(CEPC), while the $Ξ_{bb}$ events produced are forecasted to be of the $10^3(10^6)$ order. Furthermore, we have estimated the production ratio ${\cal R}(Z_Q\toΞ^{+,0}_{bc})$ with four $Z$-boson decay channels. The ${\cal R}(Z_Q\toΞ^{+,0}_{bc})$ up to $10^{-6}$ for $Z\to c\bar c$ channel and $10^{-5}$ for $Z\to b\bar b$ channel, respectively. Finally, we present the differential decay widths of $Ξ_{bc}(Ξ_{bb})$ with respect to $s_{23}$ and $z$ distributions, and analysis the uncertainties.

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arXiv2022

Next-to-leading-order QCD correction to the exclusive double charmonium production via $Z$ decays

In this paper, we preformed a further research on the exclusive productions of double charmonium via $Z$-boson decay by using nonrelativistic QCD factorizations approach, where the single-photon fragmentation topologies of the QED diagrams, the interference terms between the QCD and full QED diagrams, the next-to-leading-order calculations of the interference terms are preformed. For the production of $J/ψ+J/ψ$ in $Z$-boson decay, the interference terms show a significantly phenomenological effect due to the addition of the newly calculated NLO QCD corrections. After adding together all contributions, the branching fraction $\mathcal{B}_{Z\to J/ψJ/ψ}$ still undershoots the CMS collaboration data obviously. In addition, we simultaneously complete the next-to-leading-order calculations for $Z\to J/ψ+η_c (χ_{cJ})$ with $J=(0,1,2)$. The calculated results show that the newly-calculated complete QED and cross terms will have obvious effective on the total decay widths.

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