arXiv subjects

De-Liang Yao

Publications and source records attributed to De-Liang Yao.

At least 37 records · Page 2Linked to original sources

arXiv2024

Correlation function and the inverse problem in the $BD$ interaction

We study the correlation functions of the $B^0 D^+, B^+ D^0$ system, which develops a bound state of approximately $40$ MeV, using inputs consistent with the $T_{cc}(3875)$ state. Then we address the inverse problem starting from these correlation functions to determine the scattering observables related to the system, including the existence of the bound state and its molecular nature. The important output of the approach is the uncertainty with which these observables can be obtained, considering errors in the $B^0 D^+, B^+ D^0$ correlation functions typical of current values in present correlation functions. We find that it is possible to obtain scattering lengths and effective ranges with relative high precision and the existence of a bound state. Although the pole position is obtained with errors of the order of $50 \%$ of the binding energy, the molecular probability of the state is obtained with a very small error of the order of $6\%$. All these findings can serve as motivation to perform such measurements in future runs of high energy hadron collisions.

hep-ph↗

arXiv2024

Low-energy elastic (anti)neutrino-nucleon scattering in covariant baryon chiral perturbation theory

The low-energy antineutrino- and neutrino-nucleon neutral current elastic scattering is studied within the framework of the relativistic SU(2) baryon chiral perturbation theory up to the order of $\mathcal{O}(p^3)$. We have derived the model-independent hadronic amplitudes and extracted the form factors from them. It is found that differential cross sections ${{\rm d} σ}/{{\rm d} Q^2}$ for the processes of (anti)neutrino-proton scattering are in good agreement with the existing MiniBooNE data in the $Q^2$ region $[0.13,0.20]$ GeV$^2$, where nuclear effects are expected to be negligible. For $Q^2\leq 0.13$ GeV$^2$, large deviation is observed, which is mainly owing to the sizeable Pauli blocking effect. Comparisons with the simulation data produced by the NuWro and GIENE Mento Carlo events generators are also discussed. The chiral results obtained in this work can be utilized as inputs in various nuclear models to achieve the goal of precise determination of the strangeness axial vector form factor, in particular when the low-energy MicroBooNE data are available in the near future.

hep-ph↗

arXiv2023

Reconciling experimental and lattice data of $Z_c(3900)$ in a $J/ψπ$-$D\bar{D}^*$ coupled-channel analysis

We study the $J/ψπ$ and $D\bar{D}^*$ coupled-channel system within a covariant framework. The $J/ψπ$ and $D\bar{D}^*$ invariant-mass distributions measured at 4.23~GeV and 4.26~GeV by BESIII and the finite-volume energy levels from recent lattice QCD simulations are simultaneously fitted. Phase shifts and inelasticities of the $J/ψπ$ and $D\bar{D}^*$ scattering are predicted using the resulting amplitudes. Poles corresponding to the $Z_c(3900)$ state are found in the complex energy plane and their couplings with $J/ψπ$ and $D\bar{D}^*$ are determined. Our results indicate that the current lattice data do not preclude the existence of a physical $Z_c(3900)$ state.

hep-ph↗

arXiv2023

One-loop analysis of the interactions between doubly charmed baryons and Nambu-Goldstone bosons

The interactions between the spin-$1/2$ doubly charmed baryons and Nambu-Goldstone bosons are analyzed within a manifestly relativistic baryon chiral perturbation theory up to next-to-next-to leading order, by using the so-called extended-on-mass-shell scheme. We utilize heavy diquark-antiquark symmetry to estimate the low-energy constants in the chiral effective Lagrangians. The $S$- and $P$-wave scattering lengths are predicted. We find that those diagrams, vanishing exactly in the heavy-quark limit, do contribute slightly to the $S$-wave scattering lengths in reality. The influence of the spin-$3/2$ doubly charmed baryons, as heavy-quark spin partners of the spin-$1/2$ ones, on the scattering lengths is discussed as well. Finally, $S$-wave phase shifts for elastic scattering processes are presented in the energy region near threshold. Our results in this work will not only be very useful for performing chiral extrapolations of future lattice QCD data, but also provide us chiral inputs for the investigation of the spectroscopy of doubly heavy baryons.

hep-ph↗

arXiv2022

A unified formulation of one-loop tensor integrals for finite volume effects

A unified formulation of one-loop tensor integrals is proposed for systematical calculations of finite volume corrections. It is shown that decomposition of the one-loop tensor integrals into a series of tensors accompanied by tensor coefficients is feasible, if a unit space-like four vector $n^μ$, originating from the discretization effects at finite volume, is introduced. A generic formula has been derived for numerical computations of all the involved tensor coefficients. For the vanishing external three-momenta, we also investigate the feasibility of the conventional Passarino-Veltmann reduction of the tensor integrals in a finite volume. Our formulation can be easily used to realize the automation of the calculations of finite volume corrections to any interesting quantities at one-loop level. Besides, it provides finite volume result in a unique and concise form, which is suited for, e.g., carrying out precision determination of physical observable from modern lattice QCD data.

hep-ph↗

arXiv2021

Hunting for states in the recent LHCb di-$J/ψ$ invariant mass spectrum

Partial wave analysis is performed, with effective potentials as dynamical inputs, to scrutinize the recent LHCb data on the di-$J/ψ$ invariant mass spectrum. Coupled-channel effects are incorporated in the production amplitude via final state interactions. The LHCb data can be well described. A dynamical generated pole structure, which can be identified as the $X(6900)$ state, is found. Our analysis also provides hints for the existence of three other possible states: a bound state $X(6200)$, a broad resonant state $X(6680)$ and a narrow resonant state $X(7200)$. The $J^{PC}$ quantum numbers of the $X(6680)$ and $X(6900)$ states should be $2^{++}$, while the $X(6200)$ and $X(7200)$ states prefer $0^{++}$. To determine the above states more precisely, more experimental data for the channels, such as $J/ψψ(2S)$, $J/ψψ(3770)$, di-$ψ(2S)$, are required.

hep-ph↗

arXiv2021

A Review on Partial-wave Dynamics with Chiral Effective Field Theory and Dispersion Relation

The description of strong interaction physics of low-lying resonances is out of the valid range of perturbative QCD. Chiral effective field theories have been developed to tackle the issue. Partial wave dynamics is the systematic tool to decode the underlying physics and reveal the properties of those resonances. It is extremely powerful and helpful for our understanding of the non-perturbative regime, especially when dispersion techniques are utilized simultaneously. Recently, plenty of exotic/ordinary hadrons have been reported by experiment collaborations, e.g. LHCb, Belle, and BESIII, etc.. In this review, we summarize the recent progress on the applications of partial wave dynamics combined with chiral effective field theories and dispersion relations, on related topics, with emphasis on $ππ$, $πK$, $πN$ and $\bar{K}N$ scatterings.

hep-ph↗

arXiv2021

Chiral effective Lagrangian for doubly charmed baryons up to $\mathcal{O}(q^4)$

The chiral effective meson-baryon Lagrangian for the description of interactions between the doubly charmed baryons and Goldstone bosons is constructed up to the order of $q^{4}$. The numbers of linearly independent invariant monomials of $\mathcal{O}(q^2)$, $\mathcal{O}(q^3)$ and $\mathcal{O}(q^4)$ are 8, 32 and 218, in order. The obtained Lagrangian can be used to study the chiral dynamics and relevant phenomenology of the doubly charmed baryons at complete one-loop level in future. For completeness, the non-relativistic reduction of the Lagrangian is also discussed.

hep-ph↗

arXiv2020

Dispersive Analysis of Low Energy $γN\toπN$ Process and Studies on the $N^*(890)$ Resonance

We present a dispersive representation of the $γN\rightarrow πN$ partial-wave amplitude based on unitarity and analyticity. In this representation, the right-hand-cut contribution responsible for $πN$ final-state-interaction effect are taken into account via an Omnés formalism with elastic $πN$ phase shifts as inputs, while the left-hand-cut contribution is estimated by invoking chiral perturbation theory. Numerical fits are performed in order to pin down the involved subtraction constants. It is found that good fit quality can be achieved with only one free parameter and the experimental data of the multipole amplitude $E_{0}^+$ in the energy region below the $Δ(1232)$ are well described. Furthermore, we extend the $γN\rightarrow πN$ partial-wave amplitude to the second Riemann sheet so as to extract the couplings of the $N^\ast(890)$. The modulus of the residue of the multipole amplitude $E_{0}^+$ ($S_{11pE}$) is $2.41\rm{mfm\cdot GeV^2}$ and the partial width of $N^*(890)\toγN$ at the pole is about $0.369\ {\rm MeV}$, which is almost the same as the one of $N^*(1535)$, indicating that $N^\ast(890)$ strongly couples to $πN$ system.

hep-ph↗

arXiv2020

Pole analysis on the hadron spectroscopy of $Λ_b\to J/Ψp K^-$

In this paper we study the $J/Ψp$ spectroscopy in the process of $Λ_b\to J/Ψp K^-$. The final state interactions of coupled channel $J/Ψp$ ~-~ $\bar{D} Σ_c$~-~$\bar{D}^{*} Σ_c$ are constructed based on K-matrix with the Chew-Mandelstam function. We build the $Λ_b\to J/Ψp K^-$ amplitude according to the Au-Morgan-Pennington method. The event shape is fitted and the decay width of $Λ_b\to J/Ψp K^-$ is used to constrain the parameters, too. With the amplitudes we extract out the poles and their residues. Our amplitude and pole analysis suggest that the $P_c(4312)$ should be $\bar{D}Σ_c$ molecule, the $P_c(4440)$ could be an S-wave compact pentaquark state, and the structure around $P_c(4457)$ is caused by the cusp effect. The future experimental measurement of the decays of $Λ_b\to \bar{D}Σ_c K^-$ and $Λ_b\to \bar{D}^*Σ_c K^-$ would further help to study the nature of these resonances.

hep-ph↗

arXiv2020

New parametrization of the form factors in $\bar{B}\to D\ell\barν_\ell$ decays

A new model-independent parametrization is proposed for the hadronic form factors in the semileptonic $\bar{B}\to D\ell\barν_\ell$ decay. By a combined consideration of the recent experimental and lattice QCD data, we determine precisely the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|=41.01(75)\times 10^{-3}$ and the ratio $\mathcal{R}_D=\frac{\mathcal{BR}(\bar{B}\to D τ\barν_τ)}{\mathcal{BR}(\bar{B}\to D \ell \barν_\ell)}=0.301(5)$. The coefficients in this parametrization, related to phase shifts by sumrulelike dispersion relations and hence called phase moments, encode important scattering information of the $\bar{B}\bar{D}$ interactions which are poorly known so far. Thus, we give strong hints about the existence of at least one bound and one virtual $\bar B \bar D$ $S$-wave $0^+$ states, subject to uncertainties produced by potentially sizable inelastic effects. This formalism is also applicable for any other semileptonic processes induced by the weak $b\to c$ transition.

hep-ph↗

arXiv2019

Pion photoproduction off nucleons in covariant chiral perturbation theory

Pion photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $Δ(1232)$ resonance using the $δ$ counting. The theory is compared to the available data of cross sections and polarization observables for all the charge channels. Most of the necessary low energy constants are well known from the analysis of other processes and the comparison with data strongly constrains some of the still unknown ones. The $Δ(1232)$ contribution is significant in improving the agreement with data, even at the low energies considered.

hep-ph↗

arXiv2019

Neutral-current weak pion production off the nucleon in covariant chiral perturbation theory

Neutral current single pion production induced by neutrinos and antineutrinos on nucleon targets has been investigated in manifestly relativistic baryon chiral perturbation theory with explicit $Δ(1232)$ degrees of freedom up to $\mathcal{O}(p^3)$. At low energies, where chiral perturbation theory is applicable, the total cross sections for the different reaction channels exhibit a sizable non-resonant contribution, which is not present in event generators of broad use in neutrino oscillation and cross section experiments such as GENIE and NuWro.

hep-ph↗

arXiv2019

New Insights on Low Energy $πN$ Scattering Amplitudes: Comprehensive Analyses at $\mathcal{O}(p^3)$ Level

A production representation of partial-wave $S$ matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the $\mathcal{O}(p^3)$ results obtained in covariant baryon chiral perturbation theory within the extended-on-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in $S_{11}$ and $P_{11}$ channels, as conjectured in our previous paper~\citep{Wang:2017agd}, are firmly established. Specifically, the pole mass of the $S_{11}$ hidden resonance is determined to be $(895\pm81)-(164\pm23)i$ MeV, whereas, the virtual pole in the $P_{11}$ channel locates at $(966\pm18)$ MeV. It is found that analyses at the $\mathcal{O}(p^3)$ level improves significantly the fit quality, comparing with the previous $\mathcal{O}(p^2)$ one. Quantitative studies with cautious physical discussions are also conducted for the other $S$- and $P$-wave channels.

hep-ph↗

arXiv2018

On the Existence of $N^*(890)$ Resonance in $S_{11}$ Channel of $πN$ Scatterings

Low-energy partial-wave $πN$ scattering data is reexamined with the help of the production representation of partial-wave $S$ matrix, where branch cuts and poles are thoroughly under consideration. The left-hand cut contribution to the phase shift is determined, with controlled systematic error estimates, by using the results of $\mathcal{O}(p^3)$ chiral perturbative amplitudes obtained in the extended-on-mass-shell scheme. In $S_{11}$ and $P_{11}$ channels, severe discrepancies are observed between the phase shift data and the sum of all known contributions. Statistically satisfactory fits to the data can only be achieved by adding extra poles in the two channels. We find that a $S_{11}$ resonance pole locates at $\sqrt{z_{r}}=(0.895\pm0.081)-(0.164\pm0.023)i$ GeV, on the complex $s$-plane. On the other hand, a $P_{11}$ virtual pole, as an accompanying partner of the nucleon bound-state pole, locates at $\sqrt{z_{v}}=(0.966\pm0.018)$ GeV, slightly above the nucleon pole on the real axis below threshold. Physical origin of the two newly established poles is explored to the best of our knowledge. It is emphasized that the $\mathcal{O}(p^3)$ calculation greatly improves the fit quality comparing with the previous $\mathcal{O}(p^2)$ one.

hep-ph↗

arXiv2018

Towards a new paradigm for heavy-light meson spectroscopy

Since 2003 many new hadrons, including the lowest-lying positive-parity charm-strange mesons ${D_{s0}^*(2317)}$ and ${D_{s1}(2460)}$, were observed that do not conform with quark model expectations. It was recently demonstrated that various puzzles in the charm meson spectrum find a natural resolution, if the SU(3) multiplets for the lightest scalar and axial-vector states, amongst them the ${D_{s0}^*(2317)}$ and the ${D_{s1}(2460)}$, owe their existence to the nonperturbative dynamics of Goldstone-Boson scattering off $D_{(s)}$ and $D^*_{(s)}$ mesons. Most importantly the ordering of the lightest strange and nonstrange scalars becomes natural. In this work we demonstrate for the first time that this mechanism is strongly supported by the recent high quality data on the ${B^-\to D^+π^-π^- }$ provided by the LHCb experiment. This implies that the lowest quark-model positive-parity charm mesons, together with their bottom counterparts, if realized in nature, do not form the ground-state multiplet. This is similar to the pattern that has been established for the scalar mesons made from light up, down and strange quarks, where the lowest multiplet is considered to be made of states not described by the quark model. In a broader view, the hadron spectrum must be viewed as more than a collection of quark model states.

hep-ph↗

arXiv2018

Weak pion production off the nucleon in covariant chiral perturbation theory

Weak pion production off the nucleon at low energies has been systematically investigated in manifestly relativistic baryon chiral perturbation theory with explicit inclusion of the $Δ$(1232) resonance. Most of the involved low-energy constants have been previously determined in other processes such as pion-nucleon elastic scattering and electromagnetic pion production off the nucleon. For numerical estimates, the few remaining constants are set to be of natural size. As a result, the total cross sections for single pion production on neutrons and protons, induced either by neutrino or antineutrino, are predicted. Our results are consistent with the scarce existing experimental data except in the $ν_μn\to μ^-nπ^+$ channel, where higher-order contributions might still be significant. The $Δ$ resonance mechanisms lead to sizeable contributions in all channels, especially in $ν_μp\to μ^- pπ^+$, even though the considered energies are close to the production threshold. The present study provides a well founded low-energy benchmark for phenomenological models aimed at the description of weak pion production processes in the broad kinematic range of interest for current and future neutrino-oscillation experiments.

hep-ph↗

arXiv2018

Heavy-to-light scalar form factors from Muskhelishvili-Omnès dispersion relations

By solving the Muskhelishvili-Omnès integral equations, the scalar form factors of the semileptonic heavy meson decays $D\toπ\bar \ell ν_\ell$, $D\to \bar{K} \bar \ell ν_\ell$, $\bar{B}\to π\ell \barν_\ell$ and $\bar{B}_s\to K \ell \barν_\ell$ are simultaneously studied. As input, we employ unitarized heavy meson-Goldstone boson chiral coupled-channel amplitudes for the energy regions not far from thresholds, while, at high energies, adequate asymptotic conditions are imposed. The scalar form factors are expressed in terms of Omnès matrices multiplied by vector polynomials, which contain some undetermined dispersive subtraction constants. We make use of heavy quark and chiral symmetries to constrain these constants, which are fitted to lattice QCD results both in the charm and the bottom sectors, and in this latter sector to the light-cone sum rule predictions close to $q^2=0$ as well. We find a good simultaneous description of the scalar form factors for the four semileptonic decay reactions. From this combined fit, and taking advantage that scalar and vector form factors are equal at $q^2=0$, we obtain $|V_{cd}|=0.244\pm 0.022$, $|V_{cs}|=0.945\pm 0.041$ and $|V_{ub}|=(4.3\pm 0.7)\times10^{-3}$ for the involved Cabibbo-Kobayashi-Maskawa (CKM) matrix elements. In addition, we predict the following vector form factors at $q^2=0$: $|f_+^{D\toη}(0)|=0.01\pm 0.05$, $|f_+^{D_s\to K}(0)|=0.50 \pm 0.08$, $|f_+^{D_s\toη}(0)|=0.73\pm 0.03$ and $|f_+^{\bar{B}\toη}(0)|=0.82 \pm 0.08$, which might serve as alternatives to determine the CKM elements when experimental measurements of the corresponding differential decay rates become available. Finally, we predict the different form factors above the $q^2-$regions accessible in the semileptonic decays, up to moderate energies amenable to be described using the unitarized coupled-channel chiral approach.

hep-ph↗