arXiv subjects

Dan-Dan Hu

Publications and source records attributed to Dan-Dan Hu.

18 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.

hep-ph↗

arXiv2026

Probing the $\gamma\gamma^*\to \eta^{(\prime)}$ Transition Form Factors with Newly Derived $\eta^{(\prime)}$-Meson Light-Cone Distribution Amplitudes

In the present work, we analyze the properties of the transition form factors (TFFs) for the $\gamma\gamma^*\to \eta^{(\prime)}$ process, employing the $\eta^{(\prime)}$-meson light-cone distribution amplitude (LCDA) derived within the light-cone sum rule framework. To this end, we adopt the quark-flavor mixing scheme for the $\eta^{(\prime)}$ meson, and compute the TFFs by systematically incorporating transverse-momentum corrections and contributions beyond the leading Fock state. We utilize light-cone harmonic oscillator models to parameterize the longitudinal and transverse behavior of the leading-twist light-cone wavefunction, for which the corresponding LCDA exhibits a unimodal profile. We further examine the potential contributions of intrinsic charm components to the scaled TFFs $Q^2 F_{\eta\gamma}(Q^2)$ and $Q^2 F_{\eta^\prime \gamma}(Q^2)$. Leveraging a range of values for the decay constant $f_{\eta_{c_0}}$ and implementing the $\eta$-$\eta'$-$\eta_c$ and $\eta$-$\eta^\prime$-$G$-$\eta_c$ mixing mechanisms accordingly, together with the recently updated mixing angles, we investigate the impact of the intrinsic $c\bar{c}$ and gluonic component on these observables. In high-$Q^2$ regime, $Q^2 F_{\eta^\prime\gamma}(Q^2)$ exhibits a marked increase in sensitivity to the charm quark component, whereas $Q^2F_{\eta\gamma}(Q^2)$ becomes notably stabilized. A detailed discussion of $\chi^2/d.o.f$ and $p$-values indicates that the intrinsic charm quark component is important and yields a substantial, non-negligible contribution across the entire $Q^2$ range.

hep-ph↗

arXiv2025

Light-cone sum rules analysis of the semi-leptonic $D^+_s\to f_0(980)(\to\pi^+\pi^-)e^+\nu_e$ 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 $f_{f_0}(\mu_0=1\,\text{GeV}) = 0.386\pm0.009 \, \text{GeV}$. Subsequently, we derive the first two $\xi$-moments of the leading-twist light-cone distribution amplitude $\phi_{2;f_0}$. 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 $\mathcal{B}(D^+_s \to f_0(980)(\to \pi^+\pi^-)e^+\nu_e) = (1.783^{+0.227}_{-0.189}) \times 10^{-3}$. Our theoretical predictions align well with the latest BESIII Collaboration measurements within reasonable errors.

hep-ph↗

arXiv2025

$\eta$-$\eta'$ mixing and its application in the $B^+/D^+/D_s^+\to\eta^{(\prime)}\ell^+ \nu_\ell$ decays

In this paper, we take into account the intrinsic charm and gluonic contents into the $\eta-\eta^\prime$ mixing scheme and formulate the tetramixing $\eta-\eta^\prime-G-\eta_c$ to study the mixing properties of $\eta^{(\prime)}$ mesons. Using the newly derived mixing parameters, we calculate the transition form factors (TFFs) of $B^+/D^+/D_s^+\to\eta^{(\prime)}$ within the QCD light-cone sum rules up to next-to-leading order QCD corrections and twist-4 contributions. Using the extrapolated TFFs, we then calculate the decay widths and branching fractions of the semi-leptonic decays $B^+/D^+/D_s^+\to\eta^{(\prime)}\ell^+\nu_{\ell}$. Our results are consistent with the recent Belle and BES-III measurements within reasonable errors.

hep-ph↗

arXiv2025

Status of the $D_s^+\to\phi\ell^+\nu_\ell$ decay with a chiral-odd $\phi$-meson light-cone distribution amplitude

The twist-2 distribution amplitude of the $\phi$-meson has attracted considerable interest due to its unique properties. In this work, we construct the transverse leading-twist light-cone distribution amplitude $\phi_{2;\phi}^\bot(x,\mu_0)$ of the $\phi$-meson using the light-cone harmonic oscillator model, in which a parameter $B_{2;\phi}^\bot$ dominantly control its longitudinal distribution. To explicitly isolate different twist contributions, we employ the right-handed chiral correlator for the QCD light-cone sum rules calculation of $D_s^+\to\phi$ decays, and further, we get the branching fraction, $\mathcal{B}(D_s^+ \to \phi e^+\nu_e )= (2.271_{-0.243}^{+0.291})\times 10^{-2}$ and $\mathcal{B}(D_s^+ \to \phi \mu^+\nu_\mu )=(2.250_{-0.240}^{+0.287})\times 10^{-2}$, where errors are squared average of the mentioned error sources. Furthermore, we have extracted the Cabbibo-Kobayashi-Maskawa (CKM) matrix element $|V_{cs}|=0.975_{-0.066}^{+0.067}$ with improved precision through the analysis. Finally, we calculated the polarization parameter and asymmetry parameter for the $D_s^+\to\phi$ decays.

hep-ph↗

arXiv2025

$\eta_c$ leading-twist distribution amplitude and the $B_c \to \eta_c\ell\bar\nu_\ell$ semileptonic decays using QCD Sum Rules

In this paper, we investigate the semileptonic decays $B_c \to \eta_c\ell\bar\nu_\ell$ using the quantum chromodynamics(QCD) sum rules within the framework of Standard Model (SM). We further explore the potential to probe signatures of new Physics (NP) beyond the SM through these decays. First, we derive the $\xi$-moments $\langle\xi_{2;\eta_c}^{n}\rangle$ of the $\eta_c$-meson leading-twist distribution amplitude $\phi_{2;\eta_c}$ using the QCD sum rules within the background field theory. Considering contributions from the vacuum condensates up to dimension-six, the first two nonzero $\xi$-moments at the scale of $4$ GeV are found to be $\langle\xi_{2;\eta_c}^{2}\rangle = 0.103^{+0.009}_{-0.009}$ and $\langle\xi_{2;\eta_c}^{4}\rangle = 0.031^{+0.003}_{-0.003}$. Using these moments, we then fix the Gegenbauer expansion series of $\phi_{2;\eta_c}$ and apply it to compute the $B_c \to \eta_c$ transition form factors (TFFs) using QCD light cone sum rules. Second, we extrapolate those TFFs to physically allowable $q^2$-range via a simplified series expansion, and we obtain $R_{\eta_c}|_{\rm SM} = 0.308^{+0.084}_{-0.062}$. Furthermore, we explore the potential impacts of various NP scenarios on $R_{\eta_c}$. Specifically, we compute the forward-backward asymmetry $\mathcal{A}_{\rm FB}({q^2})$, the convexity parameter $\mathcal{C}_F^\tau ({q^2})$, and the longitudinal and transverse polarizations $\mathcal{P}_L ({q^2})$ and $\mathcal{P}_T ({q^2})$ for $B_c \to \eta_c$ transitions within both the SM and two types of NP scenarios. Our results contribute to a deeper understanding of $B_c$-meson semileptonic decays and provide insights into the search for the NP beyond the SM.

hep-ph↗

arXiv2025

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

In the paper, we derive the $\xi$-moments $\langle\xi_{2;b_1}^{n;\|}\rangle$ of the longitudinal leading-twist distribution amplitude $\phi_{2;b_1}^{\|}$ 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 $\xi$-moments at the scale 1 GeV are $\langle\xi_{2;b_1}^{1;\|}\rangle= -0.647^{+0.118}_{-0.113}$ and $\langle\xi_{2;b_1}^{3;\|}\rangle = -0.328^{+0.055}_{-0.052}$, respectively. Using those moments, we then fix the Gegenbauer expansion series of $\phi_{2;b_1}^{\|}$ 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 ${\cal B}(\bar B^0 \to b_1^+(1235)e^- \bar\nu_e) = 2.179^{+0.553}_{-0.422}\times 10^{-4}$, ${\cal B}(B^0 \to b_1^-(1235)\mu^+\nu_\mu) = 2.166^{+0.544}_{-0.415}\times 10^{-4}$, ${\cal B}(B^+ \to b_1^0(1235)e^+\nu_e) = 2.353^{+0.597}_{-0.456}\times 10^{-4}$, and ${\cal B}(B^+ \to b_1^0(1235)\mu^+\nu_\mu) = 2.339^{+0.587}_{-0.448}\times 10^{-4}$, respectively.

hep-ph↗

arXiv2024

Tight upper bound of the maximal quantum violation of Gisin's elegant Bell inequality and its application in randomness certification

The violation of a Bell inequality implies the existence of nonlocality, making device-independent randomness certification possible. This paper derives a tight upper bound for the maximal quantum violation of Gisin's elegant Bell inequality (EBI) for arbitrary two-qubit states, along with the constraints required to achieve this bound. This method provides the necessary and sufficient conditions for violating the EBI for several quantum states, including pure two-qubit states and the Werner states. The lower bound of certifiable global randomness is analyzed based on the tight upper bound of the EBI for pure two-qubit states, with a comparison to the Clauser-Horne-Shimony-Holt (CHSH) inequality. The relationship between the noise level and the lower bound of certifiable global randomness with respect to the Werner states is also explored, and the comparisons with both the CHSH inequality and the chained inequality are given. The results indicate that when the state approaches a maximally entangled state within specific quantified ranges, the EBI demonstrates advantages over both the CHSH inequality and the chained inequality, potentially enhancing practical device-independent randomness generation rates.

quant-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↗

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.

hep-ph↗

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

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 ${\cal R}_{π^0/η}^{\ell}=1.108_{-0.071}^{+0.039}\times 10^{-3}$.

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

$a_1(1260)$-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 ${\cal B}(D^0\to a_1^-(1260) e^+ν_e) = (5.261_{-0.639}^{+0.745}) \times 10^{-5}$, ${\cal B}(D^+\to a_1^0(1260) e^+ν_e) = (6.673_{-0.811}^{+0.947}) \times 10^{-5}$, ${\cal B}(D^0\to a_1^-(1260) μ^+ ν_μ)=(4.732_{-0.590}^{+0.685}) \times 10^{-5}$, ${\cal B}(D^+ \to a_1^0(1260) μ^+ ν_μ)=(6.002_{-0.748}^{+0.796}) \times 10^{-5}$.

hep-ph↗

arXiv2021

$η^{(\prime)}$-meson twist-2 distribution amplitude within QCD sum rule approach and its application to the semi-leptonic decay $ D_s^+ \toη^{(\prime)}\ell^+ ν_\ell$

In this paper, we make a detailed discussion on the $η$ and $η'$-meson leading-twist light-cone distribution amplitude $ϕ_{2;η^{(\prime)}}(u,μ)$ by using QCD sum rules approach under the background field theory. Taking both the non-perturbative condensates up to dimension-six and NLO QCD corrections to the perturbative part, its first three moments $\langleξ^n_{2;η^{(\prime)}}\rangle|_{μ_0} $ with $n = (2,4,6)$ at initial scale $μ_0 = 1$ GeV can be determined. e.g. $\langleξ_{2;η}^2\rangle|_{μ_0} =0.231_{-0.013}^{+0.010}$, $\langleξ_{2;η}^4 \rangle|_{μ_0} =0.109_{-0.007}^{+0.007}$, and $\langleξ_{2;η}^6 \rangle|_{μ_0} =0.066_{-0.006}^{+0.006}$ for $η$-meson, $\langleξ_{2;η'}^2\rangle|_{μ_0} =0.211_{-0.017}^{+0.015}$, $\langleξ_{2;η'}^4 \rangle|_{μ_0} =0.093_{-0.009}^{+0.009}$, and $\langleξ_{2;η'}^6 \rangle|_{μ_0} =0.054_{-0.008}^{+0.008}$ for $η'$-meson. Next, we calculate $D_s\toη^{(\prime)}$ TFFs $f^{η^{(\prime)}}_+(q^2)$ within QCD light-cone sum rules approach up to NLO level. The values at large recoil region are $f^η_+(0) = 0.476_{-0.036}^{+0.040}$ and $f^{η'}_+(0) = 0.544_{-0.042}^{+0.046}$. After extrapolating TFFs to the allowable physical regions within the series expansion, we obtain the branching fractions of the semi-leptonic decay, i.e. $D_s^+\toη^{(\prime)}\ell^+ ν_\ell$, i.e. ${\cal B}(D_s^+\toη^{(\prime)} e^+ν_e)=2.346_{-0.331}^{+0.418}(0.792_{-0.118}^{+0.141})\times10^{-2}$ and ${\cal B}(D_s^+\toη^{(\prime)} μ^+ν_μ)=2.320_{-0.327}^{+0.413}(0.773_{-0.115}^{+0.138})\times10^{-2}$ for $\ell = (e, μ)$ channels respectively. And in addition to that, the mixing angle for $η-η'$ with $φ$ and ratio for the different decay channels ${\cal R}_{η'/η}^\ell$ are given, which show good agreement with the recent BESIII measurements.

hep-ph↗

arXiv2021

Revisiting the production of $J/ψ+η_c$ via the $e^+e^-$ annihilation within the QCD light-cone sum rules

We make a detailed study on the typical production channel of double charmoniums, $e^+e^-\to J/ψ+η_c$, at the center-of-mass collision energy $\sqrt{s}=10.58$ GeV. The key component of the process is the form factor $F_{\rm VP}(q^2)$, which has been calculated within the QCD light-cone sum rules (LCSR). To improve the accuracy of the derived LCSR, we keep the $J/ψ$ light-cone distribution amplitude up to twist-4 accuracy. Total cross sections for $e^+e^-\to J/ψ+η_c$ at three typical factorization scales are $σ|_{μ_s} = 22.53^{+3.46}_{-3.49}~{\rm fb}$, $σ|_{μ_k} = 21.98^{+3.35}_{-3.38}~{\rm fb}$ and $σ|_{μ_0} = 21.74^{+3.29}_{-3.33}~{\rm fb}$, respectively. The factorization scale dependence is small, and those predictions are consistent with the BABAR and Belle measurements within errors.

hep-ph↗

arXiv2020

Branching fractions and polarizations of $D\to V(ω,ρ, K^*) \ell ν_\ell$ within QCD LCSR

In this paper, we make a detailed study about the $D\to V$ helicity form factors (HFFs) within the framework of QCD light-cone sum rule (LCSR) up to twist-4 accuracy. After extrapolating the LCSR predictions of HFFs to the whole physical $q^2$-region, we get the longitudinal, transverse and total $|V_{cq}|$-independent decay widths of semileptonic decay $D\to V\ell^+ν_\ell$. Meanwhile, the branching fractions of these decays are also obtained by using the $D^0(D^+)$-meson lifetime, which agree well with the BES-III results within errors. As a further step, we also investigate the differential and mean predictions for charged lepton (vector meson) polarization in the final state $P_{\rm L,T}^\ell$ ($F_{\rm L,T}^\ell$), the forward-backward asymmetry ${\cal A}_{\rm FB}^\ell$, and the lepton-side convexity parameters ${\cal C}_{\rm F}^\ell$. Our predictions are consistent with Covariant Confining Quark Model results within the errors. Thus, we think the LCSR approach for HFFs is applicable for dealing with the $D$-meson semileptonic decays.

hep-ph↗

arXiv2018

Translating surfaces of the non-parametric mean curvature flow in Lorentz manifold $M^{2}\times\mathbb{R}$

In this paper, for the Lorentz manifold $M^{2}\times\mathbb{R}$, with $M^{2}$ a $2$-dimensional complete surface with nonnegative Gaussian curvature, we investigate its space-like graphs over compact strictly convex domains in $M^{2}$, which are evolving by the non-parametric mean curvature flow with prescribed contact angle boundary condition, and show that solutions converge to ones moving only by translation.

math.DG↗