arXiv subjects

Hai-Bing Fu

Publications and source records attributed to Hai-Bing Fu.

At least 19 recordsLinked to original sources

arXiv2026

Circuit and Krylov complexity of primordial perturbations of modified gravity in inflation

Taking canonical scalar field inflation as the reference case, we investigate the circuit and Krylov complexities of primordial curvature perturbations in an $f(ϕ,R)$ modified gravity inflation. We derive the evolution equations for the squeezed strength $r_k$ and squeezed angle $φ_k$, and calculate the circuit complexity, Krylov complexity, Krylov entropy, Lanczos coefficients, and effective dissipative contribution. Compared with the canonical model, the squeezed strength $r_k$ grows more slowly in the modified gravity inflation and continues to exhibit oscillations after horizon exit. Consequently, the spreading in Krylov space is suppressed and modulated through the relation $K=\sinh^2 r_k$. Modified gravity also changes the squeezed angle, thereby modifying the phase-space correlations and enhancing the oscillatory behavior of the circuit complexity. In the presence of modified gravity effects, information loss is suppressed before horizon exit, whereas it barely affects information loss after horizon exit. For the parameters considered, the Lyapunov exponent and Lanczos coefficients indicate that modified gravity has little effect on the effective degree of quantum chaoticity. These results show that $f(ϕ,R)$ modified gravity primarily reorganizes the amplitude, phase, complexity, and information loss dynamics of primordial quantum fluctuations.

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arXiv2026

Circuit Complexity of Scalar and Tensor Perturbations in Luminal Einstein--Gauss--Bonnet Inflation

We investigate the circuit complexity of primordial scalar and tensor perturbations in the luminal branch of Einstein--Gauss--Bonnet inflation. Starting from the quadratic perturbation actions, we construct the two-mode Hamiltonians and derive the evolution equations for the squeezing amplitudes and angles. Although the tensor speed is fixed to unity, the Gauss--Bonnet (GB) coupling remains dynamical through the scalar and tensor pump fields. We track the squeezing dynamics from the subhorizon to the superhorizon regime and evaluate the Nielsen wave-function complexity of the resulting two-mode squeezed states. The GB correction produces a clear separation in the squeezing amplitudes, while the unwrapped squeezing angles remain nearly phase locked. Consequently, the circuit complexity is controlled mainly by the amplitude evolution. A positive coupling enhances the scalar complexity but slightly suppresses the tensor complexity for the benchmarks considered. These opposite trends show that scalar and tensor Gaussian states retain distinct information about the same modified inflationary background even when tensor propagation is luminal.

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arXiv2026

Circuit complexity of coupled four-mode squeezed states in two-field inflation

We study the circuit complexity of coupled curvature and entropy perturbations in two-field inflation. We start from the quadratic action and derive the full Hamiltonian. The Hamiltonian includes all diagonal and off-diagonal quadratic terms. We then obtain three coupled equations for the pair amplitudes of the four-mode squeezed state. From these amplitudes, we calculate the two principal squeezing strengths. We use them to determine the Nielsen circuit complexity. For an equal-weight Gaussian circuit, the complexity takes the form $\mathcal{C}_{2,k}=\sqrt{2(r_{1k}^{2}+r_{2k}^{2})}$. It depends on the squeezing strengths but not explicitly on the squeezing angles. Our numerical results show that the complexity grows after horizon crossing in both coupled and uncoupled models. Interfield coupling changes the pair amplitudes and the four-mode squeezed state. However, its effect on the circuit complexity is small for the parameters considered. This result shows that different four-mode pair-amplitude matrices can yield similar values of the chosen equal-weight circuit complexity. The present calculation provides a reference for studying Gaussian circuit complexity in more general two-field inflationary models.

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arXiv2026

Analysis of $S$-wave $ωπ$ dynamics behavior in multi-body $B_{\ell4}$ and $B_{\ell6}$ decays

The $b_1(1235)$ state has a sizable decay width, which have longstanding puzzle in treating as a final state in theoretical calculations may lead to systematic deviations in the predicted observables. To address this issue and further explore the internal structure of this resonance, we study the multi-body semileptonic decays $B_{\ell4}$ and $B_{\ell6}$. Within the approximation where the $b_1(1235)$ resonance dominates, we study the $B_{\ell4}$ decay $B\to b_1(1235)(\toωπ)\ell^+ν_\ell$ in the QCD light-cone sum rules framework. The corresponding transition form factors (TFFs) are calculated by constructing a correlation function with a right-handed chiral current. As the main nonperturbative input for the TFFs calculation, the transverse twist-2 light-cone distribution amplitude (LCDA) of the $b_1(1235)$ resonance is constructed using the light-cone harmonic oscillator model, and the resulting LCDA exhibits a single-peak behavior. At the large-recoil region, we obtain the TFFs $V_{0, 1, 2}(0)$ and $A(0)$, together with the corresponding TFFs ratios $r_V = 1.530_{-0.016}^{+0.013}$ and $r_2 = 0.553_{-0.015}^{+0.012}$. We then further study the complete $B_{\ell4}$ decay by incorporating the $b_1(1235)\toωπ$ resonant line shape and obtain the corresponding observables. The results show that the branching ratio of the $B_{\ell4}$ decay is about $1/3$ of that obtained when $b_1(1235)$ is treated as a final state. We also account for the subsequent decay $ω\to π^+π^-π^0$ and further predicted the branching ratio of the $B_{\ell6}$ decay $B\to b_1(1235)(\toω(\to π^+π^-π^0)π)\ell^+ν_\ell$. These results may provide useful references for future experimental measurements and further theoretical studies.

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arXiv2026

Krylov complexity and oscillatory quantum dynamics in two-field inflation

We investigate Krylov-space dynamics of primordial perturbations in two-field inflation. Starting from the quadratic action for coupled curvature and entropy perturbations, we solve the mode equations with Bunch-Davies initial conditions and construct the corresponding quadratic Hamiltonian. The Gaussian quantum state is described by a four-mode squeezed state with two squeezing channels. We derive the evolution of the squeezing strength and squeezing angle and use them to evaluate the Krylov complexity, Krylov entropy, and channel-resolved Lanczos coefficients. Our numerical results show that the two channels remain weakly squeezed inside the horizon but develop different squeezing histories after horizon exit. The second channel develops strong squeezing earlier and dominates the intermediate evolution, whereas the first channel shows a delayed enhancement. The corresponding Krylov complexities exhibit distinct oscillatory structures across horizon crossing and pronounced fluctuations in the strongly squeezed superhorizon regime. These features arise from the phase-sensitive squeezing dynamics and reflect the different responses of the two channels to curvature-entropy coupling.

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arXiv2026

Quasi-four-body semileptonic decay $\bar B^0\to a_0(1450)^+ (\toπ^+ η)\ell^-\barν_\ell$ within $a_0(1450)$-resonance leading-twist LCDA under QCDSR

The finite width of broad scalar resonances should be taken into account when relating semileptonic $B$-meson transitions to experimentally reconstructable multihadron final states. The quasi-four-body semileptonic decays $\bar B^0\to a_0(1450)^+ (\toπη)\ell^-\barν_\ell$ with $\ell=(e,μ,τ)$ provide a platform for investigating the scalar $a_0(1450)^+$-resonance as the lowest-Fock-state quark-antiquark component. We calculate the first five odd $ξ$-moments of $a_0(1450)$-resonance twist-2 light-cone distribution amplitude (LCDA) using QCDSR within the background-field theory, including vacuum condensates up to dimension six. Based on these moments, two twist-2 LCDA schemes are constructed: a light-cone harmonic oscillator model (S1), whose free parameters are fitted to the first five odd moments, and a truncated Gegenbauer expansion (S2) retaining only $a_{1,3}(μ)$. The $\bar{B}^0 \to a_0(1450)^+$ transition form factors are then calculated using light-cone sum rules. At large recoil region, we present the TFFs with different scheme. The finite-width effect of $a_0(1450)$-resonance is further incorporated through a two-channel Flatté parametrization including the $πη$ and $K\bar{K}$ channels. The $πη$ invariant-mass distribution exhibits a pronounced resonance peak around $s\simeq m_{a_0(1450)}^2$. The spectra of the electron and muon channels are nearly identical, while the $τ$-channel is significantly suppressed because the larger lepton mass reduces the available phase space. After integration over the full quasi-four-body phase space, the branching fractions are given. We expect that these results will provide useful guidance for future experimental and theoretical studies of $\bar B^0\to a_0(1450)^+ (\toπη)\ell^-\barν_\ell$ decay and help improve our understanding of the internal structure of $a_0(1450)$.

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arXiv2026

Addressing the $S$-wave scalar $f_0(1500)$-resonance in quasi-four-body FCNC rare $B_s \to f_0(1500) (\to π^+ π^- ) \ell^+ \ell^- / ν\bar ν$ decays

The $f_0(1500)$ is a quite special resonance in the light scalar spectrum. Compared with other nearby resonance, it has an unexpectedly narrow decay width. Since its mass region overlaps strongly with $f_0(1370)$ and $f_0(980)$, physicists have long debated its internal structure. To explore this issue, this work adopted the conventional quark-antiquark $q\bar{q}$ picture and investigated the behavior of the $f_0(1500)$-resonance in quasi-four-body decay channels. Based on this, we constructed a twist-2 light-cone distribution amplitude(LCDA) schemes based on the light-cone harmonic oscillator model, and presented their moments $\langle ξ^n _{2;f_0(1500)} \rangle |_μ$ and Gegenbauer moments $a_{n;f_0(1500)}(μ)$ at $μ_0=1~\mathrm{GeV}$ and $μ_k= 3~\mathrm{GeV}$ for $n=1,3,5$. Meanwhile, the $B_s\to f_0(1500)$ transition form factors (TFFs) are calculated by using the QCD light-cone sum rule. Then, we obtained the three TFFs at large recoil point, {\it i.e.,} $f_ + ^{B_s f_0(1500)}(0)= 0.390_{-0.046}^{ + 0.047}$, $f_-^{B_s f_0(1500)}(0)= -0.460_{-0.055}^{ + 0.051}$, and $f_{\rm T}^{B_s f_0(1500)}(0)= 0.568^{ + 0.069}_{-0.065}$. In addition, we extrapolated TFFs to the whole physical $q^2$-region by using the simplified $z(q^2)$-series expansion. Then we computed the branching fractions of the quasi-four-body rare decays $B_s \to f_0(1500)(\to π^ + π^-)\ell^ + \ell^-$ and $B_s \to f_0(1500)(\to π^ + π^-)ν\barν$. For comparison, we also present the results of the corresponding three-body decays obtained under the narrow-width approximation. Finally, we show the distribution of the double-differential decay width $d^2Γ/ds dq^2$ for the quasi-four-body decay $B_s\to f_0(1500)(\toπ^ + π^-)μ^ + μ^-$. We hope that our predictions can provide a useful theoretical reference for future experimental measurements and phenomenological research.

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arXiv2026

Characterize the properties of $D_s^+$-meson decay constant and leptonic decays by using QCD sum rules within background field theory framework

The leptonic decays of the $D_s^+$-meson have received considerable attention in recent years. In this work, we perform a precise calculation of the decay constant $f_{D_s^+}$ using the QCD sum rules method within the background field theory framework. In our calculation, we fully include the quark propagator contributions up to dimension-six condensates. By adopting two different constraint schemes, we obtain $f_{D_s^+}^{\text{(I)}} = 253.0_{-3.1}^{+3.3}\ \text{MeV}$ and $f_{D_s^+}^{\text{(II)}} = 251.8_{-1.3}^{+1.4}\ \text{MeV}$, respectively, both of which are in good agreement with existing theoretical and experimental results. The conventional scheme follows the standard Borel window criteria, while the derivative scheme reduces the dependence of the decay constant on the Borel parameter through an auxiliary function. Based on these decay constants and incorporating the NLO electroweak radiative corrections, we further calculate the branching fractions for the three leptonic decay channels for both schemes. Combined with the latest branching fraction $\mathcal{B}(D_s^+ \to μ^+ ν_μ)$ from the PDG, we extract the CKM matrix elements $|V_{cs}|^{\text{(I)}} = 0.967 \pm 0.012$ and $|V_{cs}|^{\text{(II)}} = 0.970 \pm 0.005$ from the two schemes, respectively.

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arXiv2026

Scrutinizing lepton flavor universality and transition form factor correlation from charmed meson semileptonic decay into light strange vector $K^*$ meson

In this paper, we calculate the transition form factors (TFFs) $A_{1,2}(q^2)$ and $V(q^2)$ of $D_s^+ \to K^{*0}$ decays by using the QCD light-cone sum rule (QCD LCSR) and constructing a correlation function containing the usual current, in which the twist-2 transverse and longitudinal light-cone distribution amplitudes (LCDAs) $ϕ^λ_{2;K^{*0}}(x,μ_0)$ with $λ=(\bot,\|)$ of the $K^{*0}$ meson constitute the main source of theoretical uncertainty. Based on this, we construct these LCDAs using the light-cone harmonic oscillator model. Subsequently, the TFFs obtained in the large recoil region are $A_{1}(0)=0.579_{-0.028}^{+0.024}$, $A_{2}(0)=0.414_{-0.023}^{+0.021}$, and $V(0)=0.830_{-0.020}^{+0.020}$, and the corresponding ratios are obtained to be $r_V=1.433_{-0.090}^{+0.110}$ and $r_2=0.715_{-0.067}^{+0.075}$. Furthermore, we predict the correlation of TFFs and their corresponding ratios. Then, we extrapolate the TFFs over the whole physical $q^2$-region and calculate the decay widths and branching fractions for the semileptonic decays $D_s^+\to K^{*0}\ell^+ν_{\ell}$. The results are $\mathcal{B}(D_s^+\to K^{*0}e^+ν_{e})=(2.05_{-0.16}^{+0.13})\times 10^{-3}$ and $\mathcal{B}(D_s^+\to K^{*0}μ^+ν_μ)=(1.95_{-0.15}^{+0.13})\times 10^{-3}$. Meanwhile, we calculated the branching fraction ratio $\mathcal{R}_{μ/e}^{K^{*0}}$ to be $0.950_{-0.002}^{+0.004}$. In addition, we extract values of the CKM matrix element, obtaining $|V_{cd}|_{(e\text{-Channel})} = 0.225_{-0.005}^{+0.005}$ and $|V_{cd}|_{(μ\text{-Channel})} = 0.227_{-0.004}^{+0.011}$. Finally, we calculated the forward-backward asymmetry parameters for the $D_s^+\to K^{*0} \ell^+ν_{\ell}$ decay.

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arXiv2026

Addressing the lightest $S$-wave strange $K_0^*(700)/κ$ resonance in four-body semileptonic $\bar{B}_s^0 \to K^0π^+ \ell^-\barν_\ell$ decays

As the lightest strange scalar resonance, $K_0^*(700)$ (also called $κ$) has a large width and resides close to the $Kπ$ threshold, leading to a longstanding debate about its internal structure. Within the framework of the conventional quark-antiquark ($q\bar{q}$) picture, this paper attempts to research the behaviors of $K_0^*(700)$ resonance in the four-body final state decays. Firstly, we investigates the $K_0^*(700)$ resonance one twist-2 and two twist-3 light-cone distribution amplitudes (LCDAs), {\it i.e.} $ϕ_{2;K_0^*(700)}(x, μ)$ and $ϕ_{3;K_0^*(700)}^{p;σ}(x, μ)$ by constructing light-cone harmonic oscillator model. For the longitudinal distribution characteristics of the twist-2 LCDA, two typical parametrization schemes, {\it i.e.} $φ_{2;K_0^*(700)}^{\rm (S1)}(x)$ and $φ_{2;K_0^*(700)}^{\rm (S2)}(x)$, are adopted in this paper. Meanwhile, it has enriched theoretical predictions for the first ten-order LCDAs $ξ$-moments. Subsequently, we apply the QCD light-cone sum rules approach to compute the $\bar B_s^0 \to K_0^*(700)$ transition form factors (TFFs) $f_\pm^{\bar B_s^0 K_0^*(700)}(q^2)$ and $f_{\rm T}^{\bar B_s^0 K_0^*(700)}(q^2)$ by taking into account the perturbative $\mathcal{O}(α_s)$ corrections to the twist-2 LCDAs terms. By using the simplified series expansion parameterization, these TFFs are extrapolated over the full physical region. Then, we calculate the differential decay widths and branching fractions for four-body semileptonic decay $\bar{B}_s^0 \to K^0π^+ \ell^-\barν_\ell$ with $\ell= (e, μ, τ)$ via the $S$-wave $K_0^*(700)$ resonance, respectively. We expect that the obtained prediction results will provide valuable insights for future experiments and theoretical research.

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arXiv2026

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

Motivated by the renewed attention from the recent BESIII experiment on the semileptonic decay $D\to V \ellν_{\ell}$, we investigate semileptonic decay $D^+\to ω\ell^+ν_{\ell}$ 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) $ϕ^{\perp}_{2;ω}(x,μ)$ dominates the contribution in TFFs. We study the properties of twist-2 LCDA $ϕ^{\perp}_{2;ω}(x,μ)$ 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 $Γ_{\rm{L}}/Γ_{\rm{T}}=0.987^{+0.107}_{-0.121}$. Then, we get branching fraction $\mathcal{B}(D^+\to ωe^+ν_e)=(1.848^{+0.365}_{-0.330})\times 10^{-3}$ and $\mathcal{B}(D^+\to ωμ^+ν_μ)=(1.782^{+0.334}_{-0.303})\times 10^{-3}$, which is in good agreement with BESIII and CLEO Collaborations. Taking into account the secondary decay $ω\to π^+π^-π^0$, we predict branching fraction of five body decay as $\mathcal{B}(D^+\to ω(\to π^+π^-π^0)e^+ν_{e})=(1.648^{+0.341}_{-0.305})\times 10^{-3}$ and $\mathcal{B}(D^+\to ω(\to π^+π^-π^0)μ^+ν_μ)=(1.589^{+0.313}_{-0.281})\times 10^{-3}$. 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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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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arXiv2026

Nature of $K^*(1680)$ and $q\bar{q}$-hybrid mixing as the SU(3) partner of $η_{1}(1855)$ in the strange sector

We presents an investigation of the $K^*(1680)$ state in its strong decays into two-body finial states within the flux-tube model and quark pair creation model. Since the charge conjugation parity is not conserved in the strange sector, the conventional $q\bar{q}$ states of $J^{P(C)}=1^{-(-)}$ can mix with the lowest hybrid states with $J^{P(C)}=1^{-(+)}$. Our analysis of the $K^*(1680)$ two-body strong decays indicates that the decay pattern of $K^*(1680)$ cannot be explained by the conventional $q\bar{q}$ scenario. Meanwhile, strong evidence shows the $q\bar{q}$-hybrid mixing mechanism in the strange sector. The phenomenological consequences of such a mixing are also discussed. Our study can provide a guidance for the future search for hybrid multiplets in experiment at BESIII, LHCb, and Belle-II.

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arXiv2026

Probing $D_s^+ \to η^{(\prime)} \ell^+ν_\ell$ semileptonic decay within LCSR under chiral heavy quark effective field theory

Motivated by the successful application of Heavy Quark Effective Field Theory in describing decays from heavy to light mesons, this work explores its applicability to the semileptonic decays of charmed mesons. So in this paper we investigate the $D_s^+\to η^{(\prime)} \ell^+ ν_\ell$ transition form factors using the light-cone sum rules approach within the framework of heavy-quark effective field theory. To address the large uncertainties arsing from the $η^{(\prime)}$-meson twist-3 distribution amplitudes, we employ the right-handed chiral correlation function. By applying the converging simplified series expansion method, we extrapolate the form factors to the entire physical $q^2$-region. Our analysis yields the branching fractions precise predictions for semi-leptonic decays $D_s^+\to η^{(\prime)}\ell^+ν_\ell$ with : $\mathcal{B}(D_s^+\toη\ell^+ν_\ell)=2.300^{+0.230}_{-0.227}\%$ ($\ell = e$) and $2.249_{-0.206}^{+0.209}\%$ ($\ell = μ$); $\mathcal{B}(D_s^+\toη^\prime \ell^+ν_\ell)=0.861^{+0.095}_{-0.093}\%$ ($\ell = e$) and $0.821^{+0.082}_{-0.080}\%$ ($\ell = μ$). The derived lepton flavor universality ratios $R^η_{μ,e}=0.977^{+0.008}_{-0.006}$ and $R^{η^{\prime}}_{μ,e} = 0.953^{+0.011}_{-0.009}$ are consistent with lasted BESIII experimental measurements. Additionally, the forward-backward asymmetry parameters $\langle \mathcal{A}^η_{\rm FB}\rangle=-0.034^{+0.003}_{-0.003}$ and $\langle \mathcal{A}^{η^\prime}_{\rm FB}\rangle=-0.073^{+0.007}_{-0.008}$ suggest that no significant violation of lepton flavor universality in this decay process.

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arXiv2026

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 ν_\ell $ with $\ell=(e, μ)$ 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 $\langleξ^{n}\rangle |_μ$ and Gegenbauer moments $a_{n}(μ)$ at $μ_0=1~{\rm GeV}$ and $μ_k= 1.4~{\rm GeV}$ 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 ${dΓ}/{d\cosθ_\ell }$ over the range $\cosθ_\ell \in [-1,1]$. Subsequently, we obtain differential decay widths and branching fractions for $D^0 \to a_0(1450)^- \ell^+ ν_\ell $ and $D^- \to a_0(1450)^0 \ell^- \barν_\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^- \barν_\ell $, the forward-backward asymmetry ${\cal A}_{\rm FB}$, lepton polarization asymmetry ${\cal A}_{λ_\ell}$ and $q^2$-differential flat term~${\cal F}_{\rm H}$.

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arXiv2026

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

In the present work, we analyze the properties of the transition form factors (TFFs) for the $γγ^*\to η^{(\prime)}$ process, employing the $η^{(\prime)}$-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 $η^{(\prime)}$ 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 $Q^2 F_{ηγ}(Q^2)$ and $Q^2 F_{η^\prime γ}(Q^2)$. Leveraging a range of values for the decay constant $f_{η_{c_0}}$ and implementing the $η$-$η'$-$η_c$ and $η$-$η^\prime$-$G$-$η_c$ 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, $Q^2 F_{η^\primeγ}(Q^2)$ exhibits a marked increase in sensitivity to the charm quark component, whereas $Q^2F_{ηγ}(Q^2)$ becomes notably stabilized. A detailed discussion of $χ^2/d.o.f$ 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.

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arXiv2025

$B_{(s)} \to S(a_0(1450), K_0^*(1430), f_0(1500))$ helicity form factors within QCD light-cone sum rules

In this paper, we investigate the helicity form factors (HFFs) of the $B_{(s)}$-meson decay into a scalar meson with a mass larger than 1~GeV, {\it i.e.,} $B \to a_0(1450)$, $B_{(s)} \to K_0^*(1430)$ and $B_{s} \to f_0(1500)$ by using light-cone sum rules approach. We take the standard currents for correlation functions. To enhance the precision of our calculations, we incorporate the next-to-leading order (NLO) corrections and retain the scalar meson twist-3 light-cone distribution amplitudes. Furthermore, we extend the HFFs to the entire physical $q^2$ region employing a simplified $z$-series expansion. At the point of $q^2=1\rm{~GeV^2}$, all NLO contributions to the HFFs are negative, with the maximum contribution around $25\%$. Then, as applications of these HFFs, we analyze the differential decay widths, branching ratios, and lepton polarization asymmetries for the semi-leptonic $B_{(s)} \to S \ell \barν_\ell$, FCNC $B_{(s)} \to S \ell \bar{\ell}$ and rare $B_{(s)} \to S ν\barν$ decays. Our results are consistent with existing studies within uncertainties. The current data still suffer from large uncertainties and need to be measured more precisely, which can lead to a better understanding of the fundamental properties of light scalar mesons.

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arXiv2025

Status of the $D_s^+\toϕ\ell^+ν_\ell$ decay with a chiral-odd $ϕ$-meson light-cone distribution amplitude

The twist-2 distribution amplitude of the $ϕ$-meson has attracted considerable interest due to its unique properties. In this work, we construct the transverse leading-twist light-cone distribution amplitude $ϕ_{2;ϕ}^\bot(x,μ_0)$ of the $ϕ$-meson using the light-cone harmonic oscillator model, in which a parameter $B_{2;ϕ}^\bot$ 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 $D_s^+\toϕ$ decays, and further, we get the branching fraction, $\mathcal{B}(D_s^+ \to ϕe^+ν_e )= (2.271_{-0.243}^{+0.291})\times 10^{-2}$ and $\mathcal{B}(D_s^+ \to ϕμ^+ν_μ)=(2.250_{-0.240}^{+0.287})\times 10^{-2}$, 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 $D_s^+\toϕ$ decays.

hep-ph↗