arXiv subjects

Yin-Long Yang

Publications and source records attributed to Yin-Long Yang.

11 recordsLinked to original sources

arXiv2026

$a_0(1450)$-state twist-2 light-cone distribution amplitude moments within QCD sum rules and its implication in $\bar B^0\to a_0(1450)^+\ell^-\bar\nu_\ell$ 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 $\xi$-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 $\xi$-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 $\bar B^0\to a_0(1450)^+\ell^-\bar\nu_\ell$ 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 $D \to \pi e \nu_e$ decays and extraction of $|V_{cd}|$

In the paper, we have carried out research on the $D\to\pi$ decay process. We employ two different currents to study the $D\to\pi$ 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 $\mathcal{B}(D^0\to \pi^-e^+\nu_e)_{\text{I}} = 0.31_{-0.05}^{+0.05}$, $\mathcal{B}(D^+\to \pi^0e^+\nu_e)_{\text{I}} = 0.39_{-0.06}^{+0.06}$, $\mathcal{B}(D^0\to \pi^-e^+\nu_e)_{\text{II}} = 0.27_{-0.03}^{+0.05}$, $\mathcal{B}(D^+\to \pi^0e^+\nu_e)_{\text{II}} = 0.34_{-0.04}^{+0.06}$, 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

Non-perturbaitve effects for the isoscalar light vector $\omega$-meson in charmed meson semileptonic decays

Motivated by the renewed attention from the recent BESIII experiment on the semileptonic decay $D\to V \ell\nu_{\ell}$, we investigate semileptonic decay $D^+\to \omega \ell^+\nu_{\ell}$ within the framework of QCD light-cone sum rule in this work. By constructing correlation function with right-handed chiral current, the transverse twist-2 light-cone distribution amplitudes (LCDA) $\phi^{\perp}_{2;\omega}(x,\mu)$ dominates the contribution in TFFs. We study the properties of twist-2 LCDA $\phi^{\perp}_{2;\omega}(x,\mu)$ through light-cone harmonic oscillator model. Applying it to the TFFs, we obtained $A_1(0)$, $A_2(0)$, $V(0)$, and $A_0(0)$ at large recoil point. Two TFF ratios are $r_V=1.40^{+0.21}_{-0.19}$ and $r_2=1.01^{+0.17}_{-0.16}$. After extrapolating those TFFs to the whole physical $q^2$ region by using the simplified $z(q^2,t)$ series expansion, the ratio of longitudinal and transverse decay widths is $\Gamma_{\rm{L}}/\Gamma_{\rm{T}}=0.987^{+0.107}_{-0.121}$. Then, we get branching fraction $\mathcal{B}(D^+\to \omega e^+\nu_e)=(1.848^{+0.365}_{-0.330})\times 10^{-3}$ and $\mathcal{B}(D^+\to \omega \mu^+\nu_{\mu})=(1.782^{+0.334}_{-0.303})\times 10^{-3}$, which is in good agreement with BESIII and CLEO Collaborations. Taking into account the secondary decay $\omega\to \pi^+\pi^-\pi^0$, we predict branching fraction of five body decay as $\mathcal{B}(D^+\to \omega(\to \pi^+\pi^-\pi^0)e^+\nu_{e})=(1.648^{+0.341}_{-0.305})\times 10^{-3}$ and $\mathcal{B}(D^+\to \omega(\to \pi^+\pi^-\pi^0)\mu^+\nu_{\mu})=(1.589^{+0.313}_{-0.281})\times 10^{-3}$. Finally, we predict the forward-backward asymmetry $A_{\rm{FB}}^{\ell}$, lepton-side convexity parameter $C^{\ell}_{\rm{F}}$, longitudinal (transverse) polarization $P_{\rm{L}(\rm{T})}^{\ell}$, as well as longitudinal polarization fraction $F_{\rm{L}}^{\ell}$.

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arXiv2025

Searching the possibility of $a_0(1450)$ scalar state being a diquark structure via charmed meson semileptonic decays

The internal structure of light scalar state $a_0(1450)$ has not been definitively determined, it may consist of multiple possible states. Among them, it has the possibility of being regarded as a diquark state. Based on this possibility, we use QCD light-cone sum rules to study the semileptonic decay process $D \to a_0(1450)\ell \nu_\ell $ with $\ell=(e, \mu)$ to verify its rationality. Firstly, we construct two types of twist-2 light-cone distribution amplitude schemes based on the light-cone harmonic oscillator model, and present their moments $\langle\xi^{n}\rangle |_{\mu}$ and Gegenbauer moments $a_{n}(\mu)$ at $\mu_0=1~{\rm GeV}$ and $\mu_k= 1.4~{\rm GeV}$ for $n=(1,3,5)$. In the large recoil region, we obtain the transition form factors (TFFs): $f_+^{\rm (S1)}(0) = 0.836_{-0.116}^{+0.119}$, $f_+^{\rm (S2)}(0)=0.767_{-0.105}^{+0.106}$ and $f_-(0)=0.630_{-0.077}^{+0.078}$. A simplified series expansion $z(q^2, t)$ is used to extrapolate TFFs to the entire physical $q^2$-region. For $q^2=10^{-5} ~{\rm GeV}^2$, we compute angular distribution of the differential decay width ${d\Gamma}/{d\cos\theta_\ell }$ over the range $\cos\theta_\ell \in [-1,1]$. Subsequently, we obtain differential decay widths and branching fractions for $D^0 \to a_0(1450)^- \ell^+ \nu_\ell $ and $D^- \to a_0(1450)^0 \ell^- \bar{\nu}_\ell $, where the branching fractions being of order $10^{-6}$. Finally, we analyze three angular observables for the semileptonic decay process $D^- \to a_0(1450)^0 \ell^- \bar{\nu}_\ell $, the forward-backward asymmetry ${\cal A}_{\rm FB}$, lepton polarization asymmetry ${\cal A}_{\lambda_\ell}$ and $q^2$-differential flat term~${\cal F}_{\rm H}$.

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arXiv2025

Exploring the exclusive decay $B^+\to \omega\ell^+\nu$ with light-cone sum rules

In this paper, we calculate the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|$ by the semileptonic decay $B^+\to \omega\ell^+\nu$. For the transition form factors (TFFs) $A_1(q^2)$, $A_2(q^2)$, and $V(q^2)$ of $B^+\to \omega$, we employ the QCD light-cone sum rules method for calculation, and by constructing the correlation function using left-handed chiral current, we make the $\delta^1$-order twist-2 light-cone distribution amplitudes (LCDA) $\phi^\| _{2;\omega}(x,\mu)$ dominate the contribution, in which the twist-2 LCDA $\phi^\| _{2;\omega}(x,\mu)$ is constructed by the light-cone harmonic oscillator model. Then, we obtain $A_1(0)=0.209^{+0.049}_{-0.042}$, $A_2(0)=0.206^{+0.051}_{-0.042}$, and $V(0)=0.258^{+0.058}_{-0.048}$ at the large recoil region. Two important ratios of TFFs are $r_V=1.234_{-0.322}^{+0.425}$ and $r_2=0.985_{-0.274}^{+0.347}$. After extrapolating TFFs to the whole physical $q^2$ region by a simplified $z(q^2,t)$-series expansion, we obtain the differential decay width and branching fraction $\mathcal{B}(B^+\to \omega\ell^+\nu)=(1.35^{+0.02+1.22}_{-0.03-0.66})\times 10^{-4}$, which show good agreement with \textit{BABAR} and Belle Collaborations. Finally, we extract the $|V_{ub}|$ by using the $\mathcal{B}_{\rm{Exp}}(B^+\to \omega\ell^+\nu)$ result from the \textit{BABAR} Collaboration, which leads to $|V_{ub}|=(3.66^{+0.12+1.26}_{-0.17-0.95})\times 10^{-3}$.

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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 $B\to D\ell^+\nu_{\ell}$, which lead to the results $\mathcal{B}(B^0\to D^-\ell ^+\nu _{\ell}) =(2.10_{-0.38}^{+0.44})\times 10^{-2}$ and $\mathcal{B}(B^+\to \bar{D}^0\ell ^+\nu _{\ell}) =(2.26_{-0.41}^{+0.48})\times 10^{-2}$. 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 $B^0\to D^-\ell^+\nu_{\ell}$, $|V_{cb}|_{\rm SR}=40.54_{-3.80}^{+4.33}\times 10^{-3}$ and $|V_{cb} |_{\rm MC}=40.46_{-1.38}^{+1.40}\times 10^{-3}$ from $B^+\to \bar{D}^0\ell^+\nu_{\ell}$ which are in good agreement with theoretical and experimental predictions.

hep-ph↗

arXiv2024

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

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 $D^+\to \ell^+\nu_{\ell}$ with $\ell=(e,\mu,\tau)$ 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 $\Gamma(D^+\to e^+\nu_e)=(5.263_{-0.075}^{+0.076})\times10^{-21}~\mathrm{GeV}$, $\Gamma(D^+\to \mu^+\nu_{\mu})=(2.236_{-0.032}^{+0.032})\times10^{-16}~\mathrm{GeV}$ and $\Gamma(D^+\to \tau^+\nu_{\tau})=(5.958_{-0.085}^{+0.086})\times10^{-16}~\mathrm{GeV}$. Accordingly, we compute the branching fraction $\mathcal{B}(D^+\to\ell^+\nu_{\ell})$ with the electron, muon and tau channels, which are $\mathcal{B}(D^+\to e^+\nu_e)=(8.260_{-0.118}^{+0.119})\times10^{-9}$, $\mathcal{B}(D^+\to\mu^+\nu_{\mu})=(3.508_{-0.050}^{+0.051})\times10^{-4}$ and $\mathcal{B}(D^+\to\tau^+\nu_{\tau})=(0.935_{-0.013}^{+0.013})\times10^{-3}$. Furthermore, we present our prediction for the CKM matrix element $|V_{cd}|$ using the branching fraction $\mathcal{B}(D^+\to\mu^+\nu_{\mu})$ 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 $b\to s \ell^+\ell^-(\nu\bar\nu)$ transition

In this paper, we investigate the rare decay $B^0\to K_0^*(1430)\ell^+\ell^-$ with $\ell=(e,\mu,\tau)$ and $B^0\to K_0^*(1430)\nu\bar{\nu}$ induced by the flavor changing neutral current transition of $b\to s\ell^+\ell^-(\nu\bar\nu)$. 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 $B^0\to K_0^*(1430)\ell^+\ell^-(\nu\bar{\nu})$ decay widths, branching fractions, and longitudinal lepton polarization asymmetries of $B^0\to K_0^*(1430)\ell^+\ell^-$, which lead to ${\cal B}(B^0\to K_0^*(1430)e^+e^-) = (6.65^{+2.52}_{-2.42})\times 10^{-7}$, ${\cal B}(B^0\to K_0^*(1430)\mu^+\mu^-)=(6.62^{+2.51}_{-2.41})\times 10^{-7}$, ${\cal B}(B^0\to K_0^*(1430)\tau^+\tau^-)=(1.88^{+1.10}_{-0.97})\times 10^{-8}$, ${\cal B}(B^0\to K_0^*(1430)\nu\bar{\nu})= 3.85^{+1.55}_{-1.48}\times 10^{-6}$ and the integrated longitudinal lepton polarization asymmetries $\langle A_{P_L} \rangle = (-0.99, -0.96, -0.03)$ for the cases $\ell=(e, \mu, \tau)$ respectively.

hep-ph↗

arXiv2024

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

In this paper, we calculate the semileptonic decays $D\to K_0^\ast(1430)\ell\nu_{\ell}$ with $\ell=(e,\mu)$ induced by $c\to s\ell\nu_{\ell}$ 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 $\xi$ 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 $D^0\to K_0^{\ast +}(1430)\ell^-\bar\nu_\ell$ and $D^+\to K_0^{\ast 0}(1430)\ell^+\nu_\ell$, 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.

hep-ph↗

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. $\mathcal{R}_{K^0/η}^e=0.144_{-0.020}^{+0.028}$.

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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