arXiv subjects

De-Liang Yao

Publications and source records attributed to De-Liang Yao.

At least 19 recordsLinked to original sources

arXiv2026

The $D_{s1}(2460)$ and other open-charm $1^+$ states in relativistic chiral effective field theory

We derive the pertinent chiral potentials for charmed vector meson interactions with light pseudoscalar bosons in a relativistic U(3) chiral effective field theory up to next-to-leading order. Predictions for the $S$- and $P$-wave scattering lengths are obtained for all the relevant elastic channels. A comparison with the most recent -- and currently the sole -- lattice QCD data on the $S$-wave $I=1/2$ $D^\astπ$ scattering length at a pion mass of $391$~MeV reveals good agreement, thereby validating the estimation of low energy constants via heavy quark spin symmetry. Within the relativistic formalism, we confirm that the $D_{s1}(2460)$ can be identified with a bound state pole, while the $D_1(2430)$ corresponds to the interplay of two poles: a lower one on the second Riemann sheet and a higher one on the third Riemann sheet. We show that the $D_{s1}(2460)$ and the lower $D_1(2430)$ pole originate from the same flavor SU(3) triplet, whereas the higher $D_1(2430)$ pole belongs to the SU(3) sextet. All these states are not of $\bar{q}q$ nature, as they flow to complex infinity in the large $N_C$ limit. Our results provide quantitative benchmarks for future lattice QCD and femtoscopic studies.

hep-ph↗

arXiv2026

Neutrinoless double-beta decay of the $Δ^-$ resonance

The subprocess $nn\to ppe^-e^-$ is a key ingredient in the interpretation of nuclear neutrinoless double-beta decay. Intermediate $Δ$ resonances may provide additional enhancements to this transition. We take a first step toward a $Δ$-full description of $nn\to ppe^-e^-$ by investigating the neutrinoless double-beta decay $Δ^- \to p e^-e^-$ in the framework of chiral effective field theory. We systematically derive the long-range contribution from light-Majorana-neutrino exchange through loop diagrams and incorporate the short-range part through counterterms required by renormalization. We predict the pion-mass dependence of the decay amplitude in the kinematic configuration with collinear electrons. Furthermore, to facilitate lattice-QCD matching, we calculate the decay amplitude in the degenerate $Δ$-nucleon mass limit and provide the corresponding long-range prediction.

hep-ph↗

arXiv2026

Low-energy interactions between doubly charmed baryons and Goldstone bosons from lattice QCD

We perform a lattice QCD calculation of the $S$-wave interactions between the ground-state spin-$1/2$ doubly charmed baryons and Goldstone bosons. The lattice QCD simulations are carried out on four $2+1$ flavor Wilson-Clover ensembles generated by the CLQCD collaboration, with a lattice spacing $a=0.07746$ fm and two different pion masses, $M_π\sim 210$ and $\sim 300~\mathrm{MeV}$. Energy levels are extracted for four single channels, $Ω_{cc}\bar{K}^{(-2,1/2)}$, $Ξ_{cc}K^{(1,1)}$, $Ξ_{cc}K^{(1,0)}$, and $Ξ_{cc}π^{(0,3/2)}$, where the superscripts $(S,I)$ denote strangeness $S$ and isospin $I$. Our results indicate that the $Ξ_{cc}K^{(1,0)}$ channel is attractive, exhibiting negative energy shifts relative to the non-interacting two-hadron thresholds, while the other three channels are repulsive. Using Lüscher's finite-volume formula, we extract the near-threshold phase shifts and determine the $S$-wave scattering lengths. Furthermore, a virtual state pole is found in the $Ξ_{cc}K^{(1,0)}$ scattering amplitude. These results provide {\it ab initio} input to enable high-precision studies of the properties and spectroscopy of doubly heavy baryons.

hep-lat↗

arXiv2026

Neutrinoless double beta decays of hyperons in covariant chiral perturbation theory

Neutrinoless double beta ($0νββ$) decays of spin-1/2 hyperons are investigated in a covariant baryon chiral perturbation theory framework, extended by a $ΔL=2$ operator proportional to the Majorana neutrino mass, where $L$ denotes the lepton number. Within the light Majorana neutrino exchange mechanism, the decay amplitudes are found to emerge at the one-loop level, representing the long-range contribution. The extended-on-mass-shell scheme is employed to renormalize the one-loop amplitudes and restore consistent chiral power counting. Consequently, the differential decay rates for all accessible hyperon $0νββ$ channels are predicted and the corresponding branching ratios are more than 20 orders of magnitude smaller than the current experimental upper bounds. Interestingly, it is found that the leading contribution to hyperon $0νββ$ decay is actually from short-range counterterm operators, as required by the renormalization argument. Neutrinoless transition form factors are proposed to determine this leading contribution through future lattice QCD simulations.

hep-ph↗

arXiv2026

Semileptonic decays $D_{(s)} \to η^{(\prime)} \ell^+ ν_\ell$ from QCD Light-Cone Sum Rules

In light of recent precision measurements from BESIII, we reanalyze the $D, D_s \to η^{(\prime)}$ transition form factors using QCD light-cone sum rules, incorporating high-twist contributions and well-established next-to-leading-order QCD corrections. Our analysis confirms the chiral enhancement effect arising from twist-3 light-cone distribution amplitudes of the pseudoscalar mesons, and demonstrates a rapid convergence of the operator product expansion. The resulting high-accuracy form factors enable us to determine the optimal $η$-$η^\prime$ mixing parameters from the precise experimental data for the $D, D_s \to η^{(\prime)} \ell^+ ν_\ell$ (with $\ell = e, μ$) differential decay rates. We find that the BESIII data strongly favor a set of mixing parameters, characterized by small decay constants and a large mixing angle, in the quark flavor basis. Notably, the light-cone-sum-rule predictions for the decays $D \to η^{(\prime)} \ell^+ ν_\ell$, induced by weak $c\to d$ current, reach a precision comparable to the BESIII experimental results. Nevertheless, further refined measurements and more accurate form-factor determinations will be essential to scrutinize the potential role of gluonic components in charmed meson semileptonic decays.

hep-ph↗

arXiv2026

Hyperon neutrinoless double beta decays in chiral perturbation theory

We study the neutrinoless double beta decays of spin-1/2 hyperons, $B_1^- \to B_2^+ \ell^- \ell^-$ with $B_1^-\in \{Σ^-,Ξ^-\}$ and $B_2^+\in\{p,Σ^+\}$, which violate lepton number by two units. The decay amplitudes are computed within covariant baryon chiral perturbation theory at the one-loop level. Dalitz plots of the squared amplitude for six physical decay processes are presented in this proceeding, while a detailed numerical analysis will be presented in a forthcoming publication.

hep-ph↗

arXiv2025

Conceptual Design of the Muonium-to-Antimuonium Conversion Experiment (MACE)

The spontaneous conversion of muonium to antimuonium is one of the interesting charged lepton flavor violation phenomena offering a sensitive probe of potential new physics and serving as a tool to constrain the parameter space beyond the Standard Model. The Muonium-to-Antimuonium Conversion Experiment (MACE) is designed to utilize a high-intensity muon beam, a Michel electron magnetic spectrometer, a positron transport system, and a positron detection system, to either discover or constrain this rare process with a conversion probability of $\mathcal{O}(10^{-13})$. This article presents an overview of the theoretical framework as well as a detailed description of the experimental design for the search for muonium-to-antimuonium conversion.

hep-ex↗

arXiv2025

Gravitational form factors of pions, kaons and nucleons from dispersion relations

The gravitational form factors of pions, kaons and the nucleons are investigated by employing modern dispersive techniques and chiral perturbation theory. We determine the gravitational form factors of pions and kaons, extending our analysis to explore the pion mass dependence of these form factors at several unphysical pion masses up to 391 MeV, for which lattice results exist for the meson-meson scattering phase shifts. We also review our analysis on the nucleon gravitational form factors at the physical pion mass, and then systematically calculate various three-dimensional spatial and two-dimensional transverse density distributions for the nucleons. These results provide new insights into the mass distribution inside nucleons. As a by-product, we match our dispersion relation results and those obtained from chiral perturbation theory with external gravitational source at the next-to-next-to-leading order, yielding values for the low-energy constants $c_8=-4.28_{-0.38}^{+0.37} ~\mathrm{GeV}^{-1}$ and $c_9=-0.68_{-0.05}^{+0.06} ~\mathrm{GeV}^{-1}$. These results offer a robust benchmark for future experimental and theoretical studies.

hep-ph↗

arXiv2025

A lattice QCD study of low-energy interactions of doubly charmed baryons

We present a lattice QCD calculation of the S-wave interactions between the spin-1/2 doubly charmed baryons ($Ξ_{cc},Ω_{cc}$) and Goldstone bosons ($π,K,\bar{K}$) using the $N_f=2+1$ CLQCD ensembles with lattice spacing $a = 0.07746$ fm and two pion masses $M_π\simeq 210$ and 300 MeV. Four single-channel interactions, $I=1/2$ $Ω_{cc}\bar{K}$, $I=1$ $Ξ_{cc}K$, $I=0$ $Ξ_{cc}K$ and $I=3/2$ $Ξ_{cc}π$, are investigated, since they are free of disconnected diagrams. Lüscher's finite volume method is utilized to extract the scattering parameters in the effective range expansion, i.e., the scattering lengths and effective ranges, from the finite-volume spectra. Our obtained results agree well with previous baryon chiral perturbation theory predictions.

hep-lat↗

arXiv2025

Two-Loop Extraction of the Pion-Nucleon Sigma Term

The pion-nucleon sigma term, characterizing the mass component of Higgs origin related to $u$ and $d$ quarks inside the nucleon, is investigated within relativistic baryon chiral perturbation theory at leading two-loop order using the extended-on-mass-shell renormalization scheme. The two-loop representation of the sigma term is derived from the nucleon mass via the Feynman-Hellmann theorem and verified through a direct calculation of the forward isoscalar-scalar nucleon matrix element. We apply the derived chiral expression to extract the physical pion-nucleon sigma term by extrapolating $N_f=2+1$ lattice quantum chromodynamics (QCD) data at unphysical quark masses. We find that, at the two-loop level, the long-standing tension between lattice QCD and dispersive determinations can be naturally resolved, owing to the incorporation of intermediate $ππ$ rescattering effects that begin to contribute at two-loop order. Our final result for the nucleon sigma term based on recent lattice QCD calculations is $σ_{πN}=55.9(2.5)$ MeV. It is compatible with the result of the Roy-Steiner equation analysis and thus provides a satisfactory resolution to the previous debate between lattice QCD and phenomenological determinations.

hep-ph↗

arXiv2025

Nucleon mass in covariant baryon chiral perturbation theory at leading two-loop order

We calculate the nucleon mass within a manifestly relativistic formulation of baryon chiral perturbation theory (BChPT), extending the framework to leading two-loop order ($\mathcal{O}(p^5)$). By employing dimensional counting analysis and rigorously verifying the extended on-mass-shell scheme at this order, we obtain a complete chiral representation of the nucleon mass that preserves analyticity, respects proper power counting, and maintains renormalization-scale independence. The resulting expression exhibits excellent convergence, with $\mathcal{O}(p^5)$ contributions remaining small ($\sim 8~\rm{MeV}$). This formulation provides a robust foundation for chiral extrapolation, demonstrating remarkable agreement with lattice QCD data across a wide range of pion masses ($M_π\lesssim 300~\rm{MeV}$). The success of this calculation establishes two-loop relativistic BChPT as a precision tool for studying nucleon structure and related properties.

hep-ph↗

arXiv2025

Dispersive Determination of Nucleon Gravitational Form Factors

Being closely connected to the origin of the nucleon mass, the gravitational form factors of the nucleon have attracted significant attention in recent years. We present the first model-independent determinations of the gravitational form factors of the pion and nucleon at the physical pion mass, using a data-driven dispersive approach. The so-called "last global unknown property" of the nucleon, the $D$-term, is determined to be $-3.38^{+0.34}_{-0.35}$. The root mean square radius of the scalar trace density inside the nucleon is determined to be $(0.97 \pm0.03)~\text{fm}$. Notably, this value is larger than the proton charge radius, suggesting a modern structural view of the nucleon where gluons, responsible for most of the nucleon mass, are distributed over a larger spatial region than quarks, which dominate the charge distribution, indicating that the radius of the trace density may be regarded as a confinement radius. We also predict the nucleon angular momentum and mechanical radii, providing further insights into the intricate internal structure of the nucleon.

hep-ph↗

arXiv2025

Semileptonic Decays of $D \to ρl^+ ν$ and $D_{(s)} \to K^\ast l^+ ν$ from Light-Cone Sum Rules

We investigate the semileptonic decays of charmed mesons to light vector mesons within the framework of light-cone sum rules. Our calculation is performed at leading order in QCD coupling, incorporating contributions up to twist-five accuracy from both two-particle and three-particle light-cone distribution amplitudes. Transition form factors are predicted twist by twist to assess the convergence property of the operator product expansion. It is verified that the twist-four and twist-five contributions are indeed negligible for all the decays under consideration. Twist-three dominance is observed for some of the form factors, subject to heavy quark effective field theory interpretation. Branching ratios for the decays $D^+ \to ρ^0 \ell^+ν_\ell$ , $D_s^+ \to K^{\ast0} \ell^+ν_\ell$, $D^0 \to K^{\ast-} \ell^+ν_\ell$ and $D^+ \to \bar{K}^{\ast0} \ell^+ν_\ell$ are obtained, and a $10\%$--$20\%$ discrepancy from experimental measurements is found. Our finding indicates that the resonant-width and non-resonant QCD backgrounds effects should be potentially significant, implying the necessity to further implement their contributions in future precision studies of the semileptonic charm decays.

hep-ph↗

arXiv2025

Karmarkar-Tolman Embedded Charged Anisotropic Stars in f(R) Gravity

We investigate various anisotropic spherical distributions of charged celestial bodies within the context of f(R) gravity, where R represents the Ricci scalar. The properties of specific charged compact objects are analyzed by using the Karmarkar-Tolman spacetime and three distinct gravitational models. The behavior of the structural parameters is examined via graphical methods. Energy constraints are applied to assess how well the results align with the Karmarkar-Tolman spacetime model. The physical acceptability of the stellar models is evaluated by checking the energy conditions and the equation of state parameter. Additionally, we explore the influence of anisotropy on the stability and internal structure of the models. Our findings are compared with predictions from general relativity to highlight the effects of f(R) gravity on charged compact stars. The obtained results are useful to enhance our understanding of how modified gravity theories affect the properties of compact astrophysical objects.

gr-qc↗

arXiv2025

ChPT and lattice QCD studies of doubly charmed baryons

The scattering lengths on the interactions between the spin-$1/2$ doubly charmed baryons and Nambu-Goldstone bosons are of great importance for the investigation of the spectroscopy of heavy flavored baryons. To that end, we have conducted a systematic analysis of the low-energy dynamics of doubly charmed baryons within the frameworks of chiral perturbation theory (ChPT) and lattice quantum chromodynamics (QCD). On the one hand, the S- and P-wave scattering lengths are predicted in a manifestly relativistic baryon ChPT at leading one-loop order. On the other hand, results of the S-wave scattering lengths for four elastic scattering single channels are obtained in lattice QCD for the first time.

hep-ph↗

arXiv2025

Chiral Representation of the Nucleon Mass at Leading Two-loop Order

We calculate the nucleon mass in a manifestly relativistic baryon chiral perturbation theory up to the leading two-loop order. Through dimensional counting analysis, we perform the chiral expansion and verify the validity of the extended-on-mass-shell scheme at the two-loop level. As a result, we obtain the complete chiral representation of the nucleon mass up to $\mathcal{O}(p^5)$, which preserves the original analytic properties and satisfies the correct power counting. The obtained chiral result is well-suited for chiral extrapolation and provides an excellent description of lattice QCD data across a broad range of pion masses. We find that the $\mathcal{O}(p^5)$ contribution is small, approximately $10$ MeV, and varies only mildly with increasing pion mass, demonstrating good convergence of the nucleon mass up to pion masses of about 350 MeV at two-loop order.

hep-ph↗

arXiv2025

Role of $a_0(980)$ in the decays $D^{0} \rightarrow K^{+} K^{-} η$ and $π^{+} π^{-} η$

In present work, we study the reactions $D^{0} \rightarrow K^{+} K^{-} η$ and $D^0 \rightarrow π^{+} π^{-} η$, and find that the $a_0(980)$ state plays a dominant role. At the quark level, the external and internal $W$-emission mechanisms are taken into account, which can hadronize into the final states, and then the $a_0(980)$ state is generated from the final state interaction. Besides, the contributions of other intermediate resonances, such as $ρ(770)$ and $ϕ(1020)$, are also considered. We make a combined fit of the invariant mass spectra measured by the Belle and BESIII Collaborations, where the results are in good agreement with the experiments, and the signal of the $a_0(980)$ shows great significance. Besides, the antisymmetry data for the production of the $a_0(980)^+$ and $a_0(980)^-$ is described well in the combined fit.

hep-ph↗

arXiv2025

Double pion photoproduction off nucleons in covariant chiral perturbation theory

The double pion photoproduction off nucleons near threshold is analyzed in a covariant baryon chiral perturbation theory up to next to leading order, where the $Δ(1232)$, $N^*(1400)$ and $ρ(770)$ resonances are included as explicit degrees of freedom. For the process $γp \to π^+ π^0 n$, the chiral results of total cross sections, invariant-mass distributions and beam-helicity asymmetry are in good agreement with the experimental data within uncertainties. For the process $γp \to π^0 π^0 p$, the prediction of total cross section deviates from the existing experimental data. Once the final-state interaction of $ππ$ in the isoscalar S-wave channel is taken into account, a good description of the cross section is achieved. The effect of the Roper resonance always turns out be negligible, and hence can be thrown away in future study of this process.

hep-ph↗