arXiv subjects

Zhaofeng Liu

Publications and source records attributed to Zhaofeng Liu.

At least 19 recordsLinked to original sources

arXiv2026

Scalar glueball-$s\bar{s}$ mixing in one flavor lattice QCD

We investigate the mixing between the lowest-lying scalar glueball and the $s\overline{s}$ meson in $N_f=1$ lattice quantum chromodynamics (QCD) utilizing an anisotropic $16^3 \times 128$ lattice ensemble at a lattice spacing $a_s\approx 0.148\,\rm{fm}$. By solving a generalized eigenvalue problem (GEVP) for the optimized glueball and $s\overline{s}$ scalar operators in the $J^\text{PC} = 0^{++}$ channel, the masses of the two lowest-lying eigenstates are determined to be $m_1 = 1.290(20)\,\mathrm{GeV}$ and $m_2 = 1.777(49)\,\mathrm{GeV}$. By extracting the couplings of these mass eigenstates to the glueball and $s\bar{s}$ operators, we determine a substantial mixing angle $|\theta| \approx 40.7(2.7)^\circ$ and a large mixing energy $x_s = 239(24)$ MeV. These results indicate a strong glueball-$s\bar{s}$ mixing in the scalar sector, providing important non-perturbative inputs for understanding the nature of the experimental isoscalar scalar mesons. The continuum limit of the mixing energy and its quark mass dependence need to be investigated in the future.

hep-lat↗

arXiv2025

Form factors of the $D_s \to ϕ\ell ν_\ell$ semileptonic decay with (2+1)-flavor lattice QCD

We present a systematic lattice calculation of the vector and axial vector form factors $V$ and $A_i~(i=0,1,2)$ for the $D_s \to ϕ\ell ν_\ell$ semileptonic decay using (2+1)-flavor Wilson-clover fermion configurations generated by the CLQCD collaboration. Seven gauge ensembles with different lattice spacings, from $0.052~\text{fm}$ to $0.105~\text{fm}$, and different pion masses, from about $210~\text{MeV}$ to $320~\text{MeV}$ are utilized, enabling us to take both the continuum limit and physical pion mass extrapolation. The form factor ratios are obtained to be $r_V=1.614(19)$ and $r_2=0.741(31)$. Our results of form factors reach the precision of $1\%-4\%$, which greatly improves the previous lattice QCD results and obtains the most precise determination to date.

hep-lat↗

arXiv2025

COMET: A Dual Swashplate Autonomous Coaxial Bi-copter AAV with High-Maneuverability and Long-Endurance

Coaxial bi-copter autonomous aerial vehicles (AAVs) have garnered attention due to their potential for improved rotor system efficiency and compact form factor. However, balancing efficiency, maneuverability, and compactness in coaxial bi-copter systems remains a key design challenge, limiting their practical deployment. This letter introduces COMET, a coaxial bi-copter AAV platform featuring a dual swashplate mechanism. The coaxial bi-copter system's efficiency and compactness are optimized through bench tests, and the whole prototype's efficiency and robustness under varying payload conditions are verified through flight endurance experiments. The maneuverability performance of the system is evaluated in comprehensive trajectory tracking tests. The results indicate that the dual swashplate configuration enhances tracking performance and improves flight efficiency compared to the single swashplate alternative. Successful autonomous flight trials across various scenarios verify COMET's potential for real-world applications.

cs.RO↗

arXiv2025

Study of the $D_s \to ϕ\ell ν_\ell$ semileptonic decay with (2+1)-flavor lattice QCD

We present a systematic lattice calculation of the $D_s \to ϕ\ell ν_\ell$ semileptonic decay using (2+1)-flavor Wilson-clover fermion configurations generated by the CLQCD collaboration. Seven gauge ensembles with different lattice spacings, from $0.052~\text{fm}$ to $0.105~\text{fm}$, and different pion masses, from about $210~\text{MeV}$ to $320~\text{MeV}$ are utilized, enabling us to take both the continuum limit and physical pion mass extrapolation. The ratios of form factors are obtained to be $r_V=1.614(19)$ and $r_2=0.741(31)$, with the precision improved by up to an order of magnitude compared to previous lattice studies. The branching fractions are given as $\mathcal{B}(D_s\toϕeν_e)=2.493(66)_{\text{stat}}(31)_{|V_{cs}|}\times 10^{-2}$ and $\mathcal{B}(D_s\toϕμν_μ)=2.351(60)_{\text{stat}}(29)_{|V_{cs}|}\times 10^{-2}$. The corresponding ratio of the branching fractions between the lepton $μ$ and $e$ is given by $\mathcal{R}_{μ/e}=0.9432(13)$, which provides essential theoretical support for future high-precision experimental tests of the lepton flavor universality. The CKM matrix element $|V_{cs}|$ is also extracted to be $0.952(12)_{\text{stat}}(23)_{\text{PDG}}$ and $0.945(12)_{\text{stat}}(24)_{\text{PDG}}$ for the $μ$ and $e$ channels, respectively.

hep-lat↗

arXiv2025

How to Unlock Time Series Editing? Diffusion-Driven Approach with Multi-Grained Control

Recent advances in time series generation have shown promise, yet controlling properties in generated sequences remains challenging. Time Series Editing (TSE) - making precise modifications while preserving temporal coherence - consider both point-level constraints and segment-level controls that current methods struggle to provide. We introduce the CocktailEdit framework to enable simultaneous, flexible control across different types of constraints. This framework combines two key mechanisms: a confidence-weighted anchor control for point-wise constraints and a classifier-based control for managing statistical properties such as sums and averages over segments. Our methods achieve precise local control during the denoising inference stage while maintaining temporal coherence and integrating seamlessly, with any conditionally trained diffusion-based time series models. Extensive experiments across diverse datasets and models demonstrate its effectiveness. Our work bridges the gap between pure generative modeling and real-world time series editing needs, offering a flexible solution for human-in-the-loop time series generation and editing. The code and demo are provided for validation.

cs.LG↗

arXiv2025

ELABORATION: A Comprehensive Benchmark on Human-LLM Competitive Programming

While recent research increasingly emphasizes the value of human-LLM collaboration in competitive programming and proposes numerous empirical methods, a comprehensive understanding remains elusive due to the fragmented nature of existing studies and their use of diverse, application-specific human feedback. Thus, our work serves a three-fold purpose: First, we present the first taxonomy of human feedback consolidating the entire programming process, which promotes fine-grained evaluation. Second, we introduce ELABORATIONSET, a novel programming dataset specifically designed for human-LLM collaboration, meticulously annotated to enable large-scale simulated human feedback and facilitate costeffective real human interaction studies. Third, we introduce ELABORATION, a novel benchmark to facilitate a thorough assessment of human-LLM competitive programming. With ELABORATION, we pinpoint strengthes and weaknesses of existing methods, thereby setting the foundation for future improvement. Our code and dataset are available at https://github.com/SCUNLP/ELABORATION

cs.AI↗

arXiv2025

Kaon Physics: A Cornerstone for Future Discoveries

The kaon physics programme, long heralded as a cutting-edge frontier by the European Strategy for Particle Physics, continues to stand at the intersection of discovery and innovation in high-energy physics (HEP). With its unparalleled capacity to explore new physics at the multi-TeV scale, kaon research is poised to unveil phenomena that could reshape our understanding of the Universe. This document highlights the compelling physics case, with emphasis on exciting new opportunities for advancing kaon physics not only in Europe but also on a global stage. As an important player in the future of HEP, the kaon programme promises to drive transformative breakthroughs, inviting exploration at the forefront of scientific discovery.

hep-ph↗

arXiv2025

Form factors in semileptonic decay of D mesons

We study the vector, scalar and tensor form factors for the semileptonic process $D\rightarrow K$ by using lattice Quantum Chromodynamcs (QCD). Chiral lattice fermions are used in our study: overlap fermion for the valence quark and domain-wall fermion for the sea. The 2+1-flavor configurations are from the RBC-UKQCD Collaborations with an inverse lattice spacing $1/a=2.383(9)$ GeV. A modified $z$-expansion taking into account valence quark mass dependence is used to fit our numerical results of the form factors at a fixed pion mass $\sim360$ MeV in the sea. At the physical valence quark mass point we give the preliminary results $f_+(0)=f_0(0)=0.760(39)$ and $f_T(0)=0.733(50)$ with only statistical uncertainties. For $f_T$ the number is given in the $\overline{\rm MS}$ scheme at a scale of 2 GeV.

hep-lat↗

arXiv2024

Charm physics with overlap fermions on 2+1-flavor domain wall fermion configurations

Decay constants of pseudoscalar mesons $D$, $D_s$, $η_c$ and vector mesons $D^*$, $D_s^*$, $J/ψ$ are determined from $N_f=2+1$ lattice QCD at a lattice spacing $a\sim0.08$ fm. For vector mesons, the decay constants defined by tensor currents are given in the $\overline{\rm MS}$ scheme at $2$ GeV. The calculation is performed on domain wall fermion configurations generated by the RBC-UKQCD Collaborations and the overlap fermion action is used for the valence quarks. Comparing the current results with our previous ones at a coarser lattice spacing $a\sim0.11$ fm gives us a better understanding of the discretization error. We obtain $f_{D_s^*}^T(\overline{\rm MS},\text{2 GeV})/f_{D_s^*}=0.907(20)$ with a better precision than our previous result. Combining our $f_{D_s^*}=277(11)$ MeV with the total width of $D_s^*$ determined in a recent work gives a branching fraction $4.26(52)\times10^{-5}$ for $D_s^*$ leptonic decay.

hep-lat↗

arXiv2024

$X(3872)$ Relevant $D\bar{D}^*$ Scattering in $N_f=2$ Lattice QCD

We study the $S$-wave $D\bar{D}^*(I=0)$ scattering at four different pion masses $m_π$ ranging from 250 MeV to 417 MeV from $N_f=2$ lattice QCD. Three energy levels $E_{2,3,4}$ are extracted at each $m_π$. The analysis of $E_{2,3}$ using the effective range expansion (ERE) comes out with a shallow bound state below the $D\bar{D}^*$ threshold, and the phase shifts at $E_{3,4}$ indicate the possible existence of a resonance near 4.0 GeV. We also perform a joint analysis to $E_{2,3,4}$ through the $K$-matrix parameterization of the scattering amplitude. In this way, we observe a $D\bar{D}^*$ bound state whose properties are almost the same as that from the ERE analysis. At each $m_π$, this joint analysis also results in a resonance pole with a mass slightly above 4.0 GeV and a width around 40-60 MeV, which are compatible with the properties of the newly observed $χ_{c1}(4010)$ by LHCb. More scrutinized lattice QCD calculations are desired to check the existence of this resonance.

hep-lat↗

arXiv2024

Evaluation of Retrieval-Augmented Generation: A Survey

Retrieval-Augmented Generation (RAG) has recently gained traction in natural language processing. Numerous studies and real-world applications are leveraging its ability to enhance generative models through external information retrieval. Evaluating these RAG systems, however, poses unique challenges due to their hybrid structure and reliance on dynamic knowledge sources. To better understand these challenges, we conduct A Unified Evaluation Process of RAG (Auepora) and aim to provide a comprehensive overview of the evaluation and benchmarks of RAG systems. Specifically, we examine and compare several quantifiable metrics of the Retrieval and Generation components, such as relevance, accuracy, and faithfulness, within the current RAG benchmarks, encompassing the possible output and ground truth pairs. We then analyze the various datasets and metrics, discuss the limitations of current benchmarks, and suggest potential directions to advance the field of RAG benchmarks.

cs.CL↗

arXiv2024

Lattice QCD calculation of the $D_s^{*}$ radiative decay with (2+1)-flavor Wilson-clover ensembles

We perform a lattice calculation on the radiative decay of $D_s^*$ using the (2+1)-flavor Wilson-clover gauge ensembles generated by CLQCD collaboration. A method allowing us to calculate the form factor with zero transfer momentum is proposed and applied to the radiative transition $D_s^*\rightarrow D_sγ$ and the Dalitz decay $D_s^*\rightarrow D_s e^+e^-$. After a continuum extrapolation using three lattice spacings, we obtain $Γ(D_s^*\rightarrow D_s γ)=0.0549(54)$ keV, where the error is purely statistical. The result is consistent with previous lattice calculations but with a error reduced to only a fifth of the before. The Dalitz decay rate is also calculated for the first time and the ratio with the radiative transition is found to be $R_{ee}=0.624(3)\%$. A total decay width of $D_s^*$ can then be determined as 0.0587(54) keV taking into account the experimental branching fraction. Combining with the most recent experimental measurement on the branching fraction of the purely leptonic decay $D_s^{+,*}\rightarrow e^+ν_e$, we obtain the quantity $f_{D_s^*}|V_{cs}|=(190.5^{+55.1}_{-41.7_{\textrm{stat.}}}\pm 12.6_{\textrm{syst.}})$ MeV, where the stat. is only the statistical error from the experiment, and syst. results from the experimental systematic uncertainty and the lattice statistical error. Our result leads to an improved systematic uncertainty compared to $42.7_{\textrm{syst.}}$ obtained using previous lattice prediction of total decay width $0.070(28)$ keV as the input.

hep-lat↗

arXiv2024

Decays of $1^{-+}$ Charmoniumlike Hybrid

By extracting the transition amplitudes, we give the first lattice QCD prediction of the two-body decay partial widths of the $1^{-+}$ charmoniumlike hybrid $η_{c1}$. Given the calculated mass value $m_{η_{c1}}=4.329(36)$ GeV, the $η_{c1}$ decay is dominated by the open charm modes $D_1\bar{D}$, $D^*\bar{D}$ and $D^*\bar{D}^*$ with partial widths of $258(133)$ MeV, $88(18)$ MeV and $150(118)$ MeV, respectively. The coupling of $η_{c1}$ to $χ_{c1}$ plus a flavor singlet pseudoscalar is not small, but $χ_{c1}η$ decay is suppressed by the small $η-η'$ mixing angle. The partial width of $η_{c1}\to η_cη'$ is estimated to be around 1 MeV. We suggest experiments to search for $η_{c1}$ in the $P$-wave $D^*\bar{D}$ and $D^*\bar{D}^*$ systems. Especially, the polarization of $D^*\bar{D}^*$ can be used to distinguish the $1^{-+}$ product (total spin $S=1$) from $1^{--}$ products ($S=0$).

hep-lat↗

arXiv2024

Form factor for Dalitz decays from $J/ψ$ to light pseudoscalars

We calculate the form factor $M(q^2)$ for the Dalitz decay $J/ψ\to γ^*(q^2)η_{(N_f=1)}$ with $η_{(N_f)}$ being the SU($N_f$) flavor singlet pseudoscalar meson. The difference among the partial widths $Γ(J/ψ\to γη_{(N_f)})$ at different $N_f$ can be attributed in part to the $\mathbf{U}_A(1)$ anomaly that induces a $N_f$ scaling. $M(q^2)$'s in $N_f=1,2$ are both well described by the single pole model $M(q^2)=M(0)/(1-q^2/Λ^2)$. Combined with the known experimental results of the Dalitz decays $J/ψ\to Pe^+e^-$, the pseudoscalar mass $m_P$ dependence of the pole parameter $Λ$ is approximated by $Λ(m_P^2)=Λ_1(1-m_P^2/Λ_2^2)$ with $Λ_1=2.64(4)~\mathrm{GeV}$ and $Λ_2=2.97(33)~\mathrm{GeV}$. These results provide inputs for future theoretical and experimental studies on the Dalitz decays $J/ψ\to Pe^+e^-$.

hep-lat↗

arXiv2023

Reinforcement Learning from Statistical Feedback: the Journey from AB Testing to ANT Testing

Reinforcement Learning from Human Feedback (RLHF) has played a crucial role in the success of large models such as ChatGPT. RLHF is a reinforcement learning framework which combines human feedback to improve learning effectiveness and performance. However, obtaining preferences feedback manually is quite expensive in commercial applications. Some statistical commercial indicators are usually more valuable and always ignored in RLHF. There exists a gap between commercial target and model training. In our research, we will attempt to fill this gap with statistical business feedback instead of human feedback, using AB testing which is a well-established statistical method. Reinforcement Learning from Statistical Feedback (RLSF) based on AB testing is proposed. Statistical inference methods are used to obtain preferences for training the reward network, which fine-tunes the pre-trained model in reinforcement learning framework, achieving greater business value. Furthermore, we extend AB testing with double selections at a single time-point to ANT testing with multiple selections at different feedback time points. Moreover, we design numerical experiences to validate the effectiveness of our algorithm framework.

cs.LG↗

arXiv2023

RI/(S)MOM renormalizations of overlap quark bilinears with different levels of hypercubic smearing

On configurations with 2+1-flavor dynamical domain-wall fermions, we calculate the RI/(S)MOM renormalization constants (RC) of overlap quark bilinears. Hypercubic (HYP) smearing is used to construct the overlap Dirac operator. We investigate the possible effects of the smearing on discretization errors in the RCs by varying the level of smearing from 0 to 1 and 2. The lattice is of size $32^3\times64$ and with lattice spacing $1/a=2.383(9)$ GeV. The RCs in the $\overline{\rm MS}$ scheme at 2 GeV are given at the end, with the uncertainty of $Z_T$ reaching $\le1$% for the tensor current. Results of the renormalized quark masses and hadron matrix elements show that the renormalization procedure suppresses the $\sim$ 30% difference of the bare quantities with or without HYP smearing into the 3%-5% level.

hep-lat↗

arXiv2023

$η$-glueball mixing from $N_f=2$ lattice QCD

We perform the first lattice study on the mixing of the isoscalar pseudoscalar meson $η$ and the pseudoscalar glueball $G$ in the $N_f=2$ QCD at the pion mass $m_π\approx 350$ MeV. The $η$ mass is determined to be $m_η=714(6)(16)$ MeV. Through the Witten-Veneziano relation, this value can be matched to a mass value of $\sim 981$ MeV for the $\mathrm{SU(3)}$ counterpart of $η$. Based on a large gauge ensemble, the $η-G$ mixing energy and the mixing angle are determined to be $|x|=107(15)(2)$ MeV and $|θ|=3.46(46)^\circ$ from the $η-G$ correlators that are calculated using the distillation method. We conclude that the $η-G$ mixing is tiny and the topology induced interaction contributes most of $η$ mass owing to the QCD $\mathrm{U_A(1)}$ anomaly.

hep-lat↗

arXiv2023

$1^{-+}$ Hybrid in $J/ψ$ Radiative Decays from Lattice QCD

We present the first theoretical prediction of the production rate of $1^{-+}$ light hybrid meson $η_1$ in $J/ψ$ radiative decays. In the $N_f=2$ lattice QCD formalism with the pion mass $m_π\approx 350$ MeV, the related electromagnetic multipole form factors are extracted from the three-point functions that involve necessarily quark annihilation diagrams, which are calculated through the distillation method. The partial width of $J/ψ\to γη_1$ is determined to be $2.29(77)~\mathrm{eV}$ at the $η_1$ mass $m_{η_1}=2.23(4)$ GeV. If $η_1$ corresponds to the recently observed $η_1(1855)$ in the process $J/ψ\to γη_1(1855)\to γηη'$ by BESIII, then the branching fraction $\mathrm{Br}(J/ψ\to γη_1(1855))$ is estimated to be $6.2(2.2)\times 10^{-5}$, which implies $\mathrm{Br}(η_1(1855)\to ηη')\sim 4.3\%$.

hep-lat↗