arXiv subjects

Fu-Wei Zhang

Publications and source records attributed to Fu-Wei Zhang.

7 recordsLinked to original sources

arXiv2026

Continuum-Limit HQET LCDAs from Lattice QCD for Tightening B Decay Uncertainties

Heavy meson HQET light-cone distribution amplitudes (LCDAs) are critical for precision predictions of $B$ meson weak decays, but currently are one of dominant theoretical uncertainties that obscure interpretations of $B$ anomalies and CP-violating measurements. Building on the established HQLaMET framework, supplemented by lattice QCD calculations of the OPE moments, we present a precise lattice QCD calculation of HQET LCDAs by employing multi-ensemble simulations for continuum and physical pion mass extrapolation, quantifying comprehensive systematic errors, and validating results through OPE moment cross-validation. Details of the lattice calculations are provided in a companion paper \cite{HeavymesonDA_long_paper}. Our final results for key inverse moments (at $\mu=1$ GeV) are $\lambda_B=0.340(20)$ GeV and $\sigma_B^{(1)}=1.685(63)$, with the total uncertainty reduced by a factor of three relative to the previous analysis. These results can greatly reduce the uncertainty in the $B \to K^*$ form factors in the large-recoil region. This work resolves the long-standing bottleneck in first-principles predictions of heavy meson LCDAs, advancing precision flavor physics to new frontiers.

hep-lat↗

arXiv2026

Determination of heavy meson light-cone distribution amplitudes: theoretical framework and lattice simulations

We present a first-principles determination of heavy meson light-cone distribution amplitudes (LCDAs) from lattice QCD in the continuum limit, improving substantially on our previous pioneering study. Within the heavy-quark large-momentum effective theory (HQLaMET) framework, supplemented by lattice QCD calculations of the OPE moments, we analyze six ensembles with lattice spacings ranging from $a=0.0519-0.1053$\,fm and pion masses from $m_\pi=135.5-317.2$\,MeV, thereby enabling controlled continuum, chiral, and infinite-momentum extrapolations to the physical point. Momentum-smeared sources, hypercubic-smeared Wilson lines, and optimized interpolating operators are adopted to significantly improved signals for the nonlocal correlators. Within a unified framework, we determine both QCD LCDAs and HQET LCDAs. Our resulting QCD LCDAs of $D$ meson peak at $y\approx 0.2-0.3$, with total uncertainties below $30\%$ for $0.1<y<0.9$. The leading-twist HQET LCDA is constructed using a peak-and-tail factorization, in which the nonperturbative peak region is obtained from lattice QCD and the perturbative tail is incorporated from HQET, with the two regions combined through a model-independent Laguerre-polynomial parametrization. At $\mu=1$\,GeV, we obtain the inverse moment of HQET LCDA $\lambda_B=0.340(20)$\,GeV and first inverse-logarithmic moment $\sigma_B^{(1)}=1.685(63)$, consistent with experimental constraints and phenomenological determinations. Direct lattice calculations based on operator product expansion provide a nontrivial cross-check of the LaMET results. Final results and phenomenological impact of these results are presented in a companion paper~\cite{HeavymesonDA_short_paper}. Our results remove the single-lattice-spacing limitation of the previous study, and provide a robust determinations of heavy meson LCDAs in both QCD and HQET for next-generation heavy flavor physics.

hep-lat↗

arXiv2025

Weak decays of singly heavy baryons: the $1/2\to3/2$ case

This work is devoted to investigating the $1/2\to3/2$ weak decays of singly heavy baryons. Due to the orthogonality between the spin wavefunctions of antitriplet baryons and spin-3/2 baryons, the weak decay amplitude for such processes vanishes at the leading order of QCD. Consequently, this study exclusively examines the weak decays of $\Omega_{Q}$. Using the light-front approach under the three-quark picture, we first extract the relevant form factors, and then apply them to investigate corresponding semileptonic and nonleptonic decays. Finally, we compare our phenomenological predictions with existing results in the literature. Our findings are expected to be helpful in experimentally establishing these decay channels.

hep-ph↗

arXiv2023

On the four-quark operator matrix elements for the lifetime of $Λ_{b}$

Heavy quark expansion can nicely explain the lifetime of $Λ_{b}$. However, there still exist sizable uncertainties from the four-quark operator matrix elements of $Λ_{b}$ in $1/m_{b}^{3}$ corrections, which describe the spectator effects. In this work, these four-quark operator matrix elements are investigated using full QCD sum rules for the first time. At the QCD level, contributions from up to dimension-6 four-quark operators are considered. Our method of calculating high-dimensional operator matrix elements is promising to be used to resolve the $Ω_{c}$ lifetime puzzle.

hep-ph↗

arXiv2023

Semi-leptonic form factors of $Ξ_{c}\toΞ$ in QCD sum rules

There exists a significant deviation between the most recent Lattice QCD simulation and experimental measurement by Belle for $Ξ_{c}^{0}\toΞ^{-}\ell^{+}ν_{\ell}$. In this work, we investigate the $Ξ_{c}\toΞ$ form factors in QCD sum rules. To this end, the two-point correlation functions of $Ξ_{c}$ and $Ξ$, and the three-point correlation functions of $Ξ_{c}\toΞ$ are calculated. At the QCD level, contributions from up to dimension-6 four-quark operators are considered, and the leading order results of the Wilson coefficients are obtained. For the form factors, relatively stable Borel windows can be found. Our form factors are comparable with those of Lattice QCD, except for $f_{\perp}$. The obtained form factors are then used to predict the branching ratios of $Ξ_{c}\toΞ\ell^{+}ν_{\ell}$, and our predictions are consistent with the most recent data of ALICE and Belle, and those of Lattice QCD within error. Given that the branching ratios only contain limited information, we suggest the experimentalists directly measure the form factors of $Ξ_{c}\toΞ$.

hep-ph↗

arXiv2023

Revisiting $Ξ_{Q}-Ξ_{Q}^{\prime}$ mixing in QCD sum rules

In this work, we perform a QCD sum rules analysis on the $Ξ_{Q}-Ξ_{Q}^{\prime}$ mixing. Contributions from up to dimension-6 four-quark operators are considered. However, it turns out that, only dimension-4 and dimension-5 operators contribute, which reveals the non-perturbative nature of mixing. Especially we notice that only the diagrams with the two light quarks participating in gluon exchange contribute to the mixing. Our results indicate that the mixing angle $θ_{c}=(1.2\sim2.8)^{\circ}$ for the $Q=c$ case and $θ_{b}=(0.28\sim0.34)^{\circ}$ for the $Q=b$ case. Our prediction of $θ_{c}$ is consistent with the most recent Lattice QCD result within error. Such a small mixing angle seems unlikely to resolve the tension between the recent experimental measurement from Belle and Lattice QCD calculation for the semileptonic decay $Ξ_{c}^{0}\toΞ^{-} e^{+}ν_{e}$.

hep-ph↗

arXiv2023

Baryons in the light-front approach: The three-quark picture

In this work, a three-quark picture is constructed using a bottom-up approach for baryons in light-front quark model. The shape parameters, which characterize the momentum distribution inside a baryon, are determined with the help of the pole residue of the baryon. The relation between the three-quark picture and the diquark picture is clarified. When building the model, we find that Lorentz boost plays a crucial role, and the bottom-up modeling approach can be generalized to multiquark states. Based on this, a unified theoretical framework for describing multiquark states may be established. As a by-product of model construction, we can easily obtain a newly improved definition of baryon interpolating current. The hadron interpolating currents are the starting point of Lattice QCD and QCD sum rules, and therefore are of great importance.

hep-ph↗