arXiv subjects

T. -S. H. Lee

Publications and source records attributed to T. -S. H. Lee.

At least 19 recordsLinked to original sources

arXiv2026

Low-lying $Λ$ and $Σ$ resonances studied with the forward $K^*$ productions off the proton induced by a high-momentum $π$ beam

We develop a novel model utilizing the forward $K^*$ production reaction off the nucleon, $πN \to K^* MB$, induced by a high-momentum $π$ beam, as a tool to study low-lying $Y^*$ resonances below and just above the $\bar{K}N$ threshold. Because conventional $K^- p$ scattering experiments face difficulties in directly accessing this kinematic region, the proposed reaction offers a valuable complementary approach for $Y^*$ spectroscopy. The constructed model is based on the one-meson exchange mechanism, which is known to dominate forward-angle production at high energies, and the half-off-shell scattering amplitudes from the ANL-Osaka dynamical coupled-channels models (Model A and Model B). We predict various observables, including differential cross sections and angular distributions. Our results demonstrate significant enhancements in the subthreshold region of the invariant mass spectra. Notably, we show that overlapping resonances, such as a potential new $3/2^+$ $Σ$ state and the well-established $Σ(1385)3/2^+$, can constitute a single peak in the $πΛ$ mass spectrum, indicating that the existence of previously unconfirmed subthreshold states cannot be ruled out by analyzing only the existing mass spectrum data. Furthermore, we find that angular distributions provide strong discriminatory power to disentangle such overlapping states through partial-wave interference effects, while the $t'$ and $ϕ_M^*$ dependencies provide crucial constraints on the high-energy production mechanisms. Our predictions for these highly sensitive observables can facilitate high-statistics measurements, which are accessible at modern hadron facilities such as J-PARC, to unravel the $S=-1$ $Y^*$ mass spectrum.

hep-ph↗

arXiv2026

Quark--hadron duality in inclusive electron--proton scattering at high $Q^{2}$: structure functions and truncated moments from CLAS12

We present a high-precision study of quark--hadron duality in inclusive electron--proton scattering in the nucleon resonance region, extending to $Q^2\approx10~\mathrm{GeV}^2$, based on recent CLAS12 cross-section measurements at Jefferson Lab. The data, taken with a 10.6~GeV beam, span $2.55 \le Q^2 \le 10.4~\mathrm{GeV}^2$ and cover the full resonance region up to $W\approx2.5~\mathrm{GeV}$. To reach the CLAS12 kinematics, we develop a phenomenological high-$Q^2$ extension of the Argonne--Osaka (ANL-Osaka) dynamical coupled-channels framework, anchored to the original calculation at $Q_0^2=2.774~\mathrm{GeV}^2$ and constrained by the measured cross sections. This enables an ANL-Osaka-constrained longitudinal--transverse decomposition and determination of the proton structure function $F_2(W,Q^2)$, from which we evaluate $W$-truncated Cornwall--Norton moments $M_2(Q^2)$. Comparison with the CJ15 global QCD analysis, including target-mass and higher-twist corrections, shows consistency at the cross-section, structure-function, and truncated-moment levels, providing quantitative evidence for both local and global quark--hadron duality at substantially higher $Q^2$ than previously explored. We further identify a threshold effect in the partonic calculation: the finite-$Q^2$ corrections do not enforce the physical pion-production threshold, and the residual discrepancy in the first resonance region is consistent with this effect rather than a breakdown of duality. Within the coupled-channel description, the single-pion channel alone underestimates the inclusive resonance-region strength above the $Δ(1232)$, which is carried predominantly by the multi-meson channels, as required for duality.

hep-ph↗

arXiv2026

Dynamical study of $πN\to ππN$ reactions revisited

Using the Argonne National Laboratory-The University of Osaka (ANL-Osaka) DCC model of meson-nucleon reactions, we extend the study of Phys. Rev. C 79, 025206 (2009) and Phys. Rev. C 88, 045203 (2013) to predict the cross sections of the $πN \to ππN$ reactions. The model was constructed by fitting only the two-body reactions: $πN,γN \to πN, ηN, KΛ, KΣ$. Thus, the results for $πN \to ππN$ presented here are predictions of the ANL-Osaka DCC model, which serve to examine the extent to which the forthcoming data from J-PARC can be described. This study provides information for improving the extraction of nucleon resonances that have large decay widths to $ππN$ states. We present results for the total cross sections, invariant mass distributions, and angular distributions. We also identify the observables and energy regions where the higher mass nucleon resonances in the $S_{31}$, $P_{33}$, $D_{33}$, $F_{37}$, $D_{13}$, $D_{15}$, and $F_{15}$ partial waves can be most effectively investigated.

hep-ph↗

arXiv2024

Exclusive $J/ψ$ photo-production on nuclei

Motivated by the recent experimental developments, the Pom-CQM model of the $γ+ N \to J/ψ+ N$ reaction of Lee et al. [Eur. Phys. J. A. 58, 252 (2022)] and Sakinah et al. [Phys. Rev. C. 109, 065204 (2024)] has been applied to predict the exclusive $J/ψ$ photo-production on nuclei ($A$). Within the multiple scattering theory, the calculations have been performed by including the impulse amplitude $T^{\rm IMP}_{J/ψA,γA}$ and the $J/ψ$-nucleus final state interaction (FSI) amplitude $T^{\rm FSI}_{J/ψA,γA}$. For the deuteron target, $T^{\rm IMP}_{J/ψd,γd}$ is calculated exactly using the wave function generated from the realistic nucleon-nucleon potentials. It is found that, near the threshold region, the $J/ψ$ photo-production cross sections depend sensitively on the $d$-state of the deuteron wave function. The FSI amplitude $T^{\rm FSI}_{J/ψA,γA}$ is calculated using the first-order optical potential constructed from the $J/ψ$-$N$ scattering amplitude generated from the employed Pom-CQM model. It turns out that the FSI has significant effects in the large momentum-transfer region. By using the conventional fixed scatter approximation (FSA) and the nuclear form factors from the variational Monte-Carlo (VMC) calculations of Lonardoni et al. [Phys. Rev.C. 96, 024326 (2017)], the cross sections of the $J/ψ$ photo-production on ${^4\rm He}$, ${^{16}\rm O}$, and ${^{40}\rm Ca}$ are also predicted for future experimental investigations at JLab and EIC.

nucl-th↗

arXiv2024

Generalized boost transformations in finite volumes and application to Hamiltonian methods

The investigation of hadron interactions within lattice QCD has been facilitated by the well-known quantisation condition, linking scattering phase shifts to finite-volume energies. Additionally, the ability to utilise systems at finite total boosts has been pivotal in smoothly charting the energy-dependent behaviour of these phase shifts. The existing implementations of the quantization condition at finite boosts rely on momentum transformations between rest and moving frames, defined directly in terms of the energy eigenvalues. This energy dependence is unsuitable in the formulation of a Hamiltonian.In this work, we introduce a novel approach to generalise the three-momentum boost prescription, enabling the incorporation of energy-independent finite-volume Hamiltonians within moving frames. We demonstrate the application of our method through numerical comparisons, employing a phenomenological $ππ$ scattering example.

hep-lat↗

arXiv2024

Dynamical Model of $J/Ψ$ photo-production on the nucleon

A dynamical model based on a phenomenological charm quark-nucleon($c$-N) potential $v_{cN}$ and the Pomeron-exchange mechanism is constructed to investigate the $J/Ψ$ photo-production on the nucleon from threshold to invariant mass $W=300$ GeV. The $J/Ψ$-N potential,$V_{J/ΨN}(r)$,is constructed by folding $v_{cN}$ into the wavefunction $Φ_{J/Ψ}(c\bar{c})$ of $J/Ψ$ within a Constituent Quark Model(CQM) of Ref.[43]. A photo-production amplitude is also generated by $v_{cN}$ by a $c\bar{c}$-loop integration over the $γ\rightarrow c\bar{c}$ vertex function and $Φ_{J/Ψ}(c\bar{c})$. No commonly used Vector Meson Dominance assumption is used to define this photo-production amplitude which is needed to describe the data near the threshold. The potential $v_{cN}(r)$ is parameterized in a form such that the predicted $V_{J/ΨN}(r)$ at large distances has the same Yukawa potential form extracted from a Lattice QCD(LQCD) calculation of Ref.[18]. The parameters of $v_{cN}$ are determined by fitting the total cross section data of JLab by performing calculations that include $J/Ψ$-N final state interactions(FSI). The resulting differential cross sections are found in good agreements with the data. It is shown that the FSI effects dominate the cross section in the very near threshold region, allowing for sensitive testing of the predicted $J/Ψ$-N scattering amplitudes. By imposing the constraints of $J/Ψ$-N potential extracted from the LQCD calculation, we have obtained three $J/Ψ$-N potentials which fit the JLab data equally well. The resulting $J/Ψ$-N scattering lengths are in the range of $a=(-0.05$ fm $\sim$ $-0.25$ fm). With the determined $v_{cN}(r)$ and the wavefunctions generated from the same CQM, the constructed model is used to predict the cross sections of photo-production of $η_c(1S)$ and $Ψ(2S)$ mesons for future experimental tests.

nucl-th↗

arXiv2022

Models of $J/Ψ$ photo-production reactions on the nucleon

The $J/Ψ$ photo-production reactions on the nucleon can provide information on the roles of gluons in determining the $J/Ψ$-nucleon ($J/Ψ$-N) interactions and the structure of the nucleon. The information on the $J/Ψ$-N interactions is needed to test lattice QCD (LQCD) calculations and to understand the nucleon resonances such as $N^*(P_c)$ recently reported by the LHCb Collaboration. In addition, it is also needed to investigate the production of nuclei with hidden charms and to extract the gluon distributions in nuclei. The main purpose of this article is to review six reaction models of $γ+ p \rightarrow J/Ψ+p$ reactions which have been and can be applied to analyze the data from Thomas Jefferson National Accelerator Facility (JLab). The formulae for each model are given and used to obtain the results to show the extent to which the available data can be described. The models presented include the Pomeron-exchange model of Donnachie and Landshoff (Pom-DL) and its extensions to include $J/Ψ$-N potentials extracted from LQCD (Pom-pot) and to also use the constituent quark model (CQM) to account for the quark substructure of $J/Ψ$ (Pom-CQM). The other three models are developed from applying the perturbative QCD approach to calculate the two-gluon exchange using the generalized parton distribution (GPD) of the nucleon (GPD-based), two- and three-gluon exchanges using the parton distribution of the nucleon ($2g+3g$), and the exchanges of scalar ($0^{++}$) and tensor ($2^{++}$) glueballs within the holographic formulation (holog). The results of investigating the excitation of the nucleon resonances $N^*(P_c)$ in the $γ+ p \rightarrow J/Ψ+p$ reactions are also given.

hep-ph↗

arXiv2021

Dynamical model of $ϕ$ meson photoproduction on the nucleon and $^4He$

We investigate $ϕ$ meson photoproduction on the nucleon and the \nuclide[4]{He} targets within a dynamical model approach based on a Hamiltonian which describes the production mechanisms by the Pomeron-exchange, meson-exchanges, $ϕ$ radiations, and nucleon resonance excitations mechanisms. The final $ϕN$ interactions are included being described by the gluon-exchange, direct $ϕN$ couplings, and the box-diagrams arising from the couplings with $πN$, $ρN$, $KΛ$, and $KΣ$ channels. The parameters of the Hamiltonian are determined by the experimental data of $γp \to ϕp$ from the CLAS Collaboration. The resulting Hamiltonian is then used to predict the coherent $ϕ$-meson production on the \nuclide[4]{He} targets by using the distorted-wave impulse approximation. For the proton target, the final $ϕN$ rescattering effects, as required by the unitarity condition, are found to be very weak, which supports the earlier calculations in the literature. For the \nuclide[4]{He} targets, the predicted differential cross sections are in good agreement with the data obtained by the LEPS Collaboration. The role of each mechanism in this reaction is discussed and predictions for a wide range of scattering angles are presented, which can be tested in future experiments.

nucl-th↗

arXiv2020

Pomeron-LQCD model of $J/Ψ$ photo-production on the nucleon

Based on the vector meson dominance assumption, a Hamiltonian model has been developed to investigate $J/Ψ$ photo-production reaction on the nucleon by using the $J/Ψ$-nucleon potential extracted from a lattice QCD calculation of Phys. Rev. D{\bf 82}, 091501 (2010). It is found that the predicted total cross sections are comparable to the recent data of $J/Ψ$ photo-production reaction from Jefferson Laboratory. The model is then extended to include the two-gluon exchange amplitude modeled by Donnachie and Lanshoff within Regge Phenomenology. The resulting Pomeron-LQCD model can then explain the data up to invariant mass $W=$ 300 GeV. Future improvements needed to reduce the uncertainties of the predictions are discussed. The need of an accurate extraction of $J/Ψ$-N potential at short distances from LQCD is illustrated.

nucl-th↗

arXiv2019

The ANL-Osaka Partial-Wave Amplitudes of $πN$ and $γN$ Reactions

The determination of the Argonne National Laboratory-Osaka University (ANL-Osaka) Partial-Wave Amplitudes (PWA) of $πN$ and $γN$ Reactions is reviewed. The predicted PWA are presented on a web page (https://www.phy.anl.gov/theory/research/anl-osaka-pwa). The formulas are given for using the predicted PWA to calculate the cross sections of (1) meson-baryon ($MB$) scattering $MB \rightarrow M'B'$ with $MB, M'B'= πN, ηN, KΛ, KΣ$, (2) two-pion production $πN \rightarrow πΔ, ρN, σN \rightarrow ππN$, (3) Meson photoproduction $γN \rightarrow πN, ηN, KΛ, KΣ$, (4) Pion electroproduction $N(e,e'π)N$, (5) inclusive $N(e,e')X$. We also present sample results from our fits to the data.

nucl-th↗

arXiv2019

Electroweak pion-production on nuclei within the extended factorization scheme

We have applied the extended factorization scheme to investigate the electroweak pion production on nuclei. The ANL-Osaka model, which was obtained by analyzing the data of $πN$, $γN$, $N(e,e'π)$ and $N(ν,μ\,π) $ reactions up to invariant mass $W=$ 2 GeV, is used to generate the matrix elements of current operators relevant to pion-production off the nucleon. Medium effects on the $Δ$ (1232) component of meson-exchange current are included by using a $Δ$-nucleus potential determined from the previous $Δ$-hole model studies of pion-nucleus reactions. Nuclear correlations in the initial target state and in the spectator system(s) are modeled using realistic hole spectral functions. As a first step, we show that the data of $^{12}$C$(e,e')$ up to the $Δ$ (1232) region can be described reasonably well. The interplay between the pion production and two-body meson-exchange mechanisms is shown to be essential in improving the agreement with the data in the ``dip'' region, between the quasielastic and the $Δ$ (1232) peaks. Predictions for $^{12}$C$(ν,μ\,π)$ have also been made. They can be used to estimate pion-emission rates in neutrino-nucleus cross section, which constitutes an important systematic uncertainty to the reconstructed neutrino energy. With further improvements of the Metropolis Monte-Carlo techniques to account for final states comprised of more than two particles, our approach can be employed up to $W=$ 2 GeV, where two-pion production and higher mass nucleon resonances must be included for analyzing the data from accelerator-based neutrino-oscillation experiments.

nucl-th↗

arXiv2019

Nucleon Resonances with Hidden Charm in $γp $ reactions

The excitations of nucleon resonances with hidden charm, $N^*_{c\bar{c}}$, in the $γp$ reactions are investigated by using the predictions from the available meson-baryons (MB) coupled-channel models. For the $γ\,p\rightarrow J/ψ\, p$ process, we first calculate the Pomeron-exchange amplitudes with the parameters determined from fitting the available total cross section data up to invariant mass $W=300$ GeV. We then add the resonant amplitudes to examine the effects of $ N^*_{c\bar{c}}$ excitations on the cross sections of $γ\,p\rightarrow J/ψ\, p$ in the near threshold energy region. The $N^*_{c\bar{c}}\to MB$ transition matrix elements are determined from the partial decay widths predicted by the meson-baryons coupled-channel models. The $γp \to N^*_{c\bar{c}}$ transition amplitudes are calculated from the Vector Meson Dominance (VMD) model. The total $γp\rightarrow J/ψ\, p$ amplitudes then depend on an off-shell form factor, parameterized as $F_V(q^2)=Λ^4/(Λ^4 + (q^2 - m^2_V)^2)$ with $Λ=550$ MeV. We then demonstrate that the $N^*_{c\bar{c}}$ can be most easily identified in the differential cross sections at large angles of outgoing $J/ψ$ where the contribution from Pomeron-exchange becomes negligible. With the same VMD model and the same coupled-channel models of $N^*_{c\bar{c}}$, we also calculate the resonant amplitudes for the $γ\,p\rightarrow Vp\rightarrow N^*_{c\bar{c}} \rightarrow \bar{D}^0Λ_c^+ (\bar{D}^{*0}Λ_c^+)$ processes. By adding the non-resonant amplitudes due to the exchange of $\bar{D}^{*0}$ ($\bar{D}^{0})$, we then predict the cross sections of $γ\,p\rightarrow \bar{D}^0Λ_c^+(\bar{D}^{*0}Λ^+_c)$ for additional experimental tests of the available meson-baryon coupled-channel models of $N^*_{c\bar{c}}$.

nucl-th↗

arXiv2018

Nuclear applications of ANL-Osaka amplitudes: pion photo-productions on deuteron

The Argonne National Laboratory-Osaka University (ANL-Osaka) amplitudes (http://www.phy.anl.gov/theory/research/anl-osaka-pwa/) are applied to study pion photo-production reactions on the deuteron target. Within the multiple scattering formulation, we predict the cross sections of $d(γ,π)NN$ in the nucleon resonance region. The calculations include the impulse term and the final-state interaction (FSI) terms due to pion-exchange and nucleon-exchange. We show that the off-shell effects, calculated from the meson-exchange mechanisms, on the propagations of the exchanged nucleon and pion are significant in determining the reaction amplitudes. The FSI effects on the predicted cross sections are found to be important at energies near the $Δ$(1232) resonance, and are still significant at higher energies. The results are in good agreement with most of the available data of $d(γ,π^0)np$ and $d(γ,π^-)pp$ reactions.

nucl-th↗

arXiv2018

Nucleon Excited States from Lattice QCD and Hamiltonian Effective Field Theory

An approach for relating the nucleon excited states extracted from lattice QCD and the nucleon resonances of experimental data has been developed using the Hamiltonian effective field theory (HEFT) method. By formulating HEFT in the finite volume of the lattice, the eigenstates of the Hamiltonian model can be related to the energy eigenstates observed in Lattice simulations. By taking the infinite-volume limit of HEFT, information from the lattice is linked to experiment. The approach opens a new window for the study of experimentally-observed resonances from the first principles of lattice QCD calculations. With the Hamiltonian approach, one not only describes the spectra of lattice-QCD eigenstates through the eigenvalues of the finite-volume Hamiltonian matrix, but one also learns the composition of the lattice-QCD eigenstates via the eigenvectors of the Hamiltonian matrix. One learns the composition of the states in terms of the meson-baryon basis states considered in formulating the effective field theory. One also learns the composition of the resonances observed in Nature. In this paper, we will focus on recent breakthroughs in our understanding of the structure of the $N^*(1535)$, $N^*(1440)$ and $Λ^*(1405)$ resonances using this method.

nucl-th↗

arXiv2016

Toward establishing low-lying $Λ$ and $Σ$ hyperon resonances with the $\bar K + d \to π+ Y + N$ reaction

A model for the $\bar K d \to πY N$ reactions with $Y=Λ, Σ$ is developed, aiming at establishing the low-lying $Λ$ and $Σ$ hyperon resonances through analyzing the forthcoming data from the J-PARC E31 experiment. The off-shell amplitudes generated from the dynamical coupled-channels (DCC) model, which was developed in Kamano et al. [Phys. Rev. C 90, 065204 (2014)], are used as input to the calculations of the elementary $\bar K N \to \bar K N$ and $\bar K N \to πY$ subprocesses in the $\bar K d \to πY N$ reactions. It is shown that the cross sections for the J-PARC E31 experiment with a rather high incoming-$\bar{K}$ momentum, $|\vec p_{\bar K}|= 1$ GeV, can be predicted reliably only when the input $\bar K N \to \bar K N$ amplitudes are generated from a $\bar KN$ model, such as the DCC model used in this investigation, which describes the data of the $\bar K N$ reactions at energies far beyond the $\bar K N$ threshold. We find that the data of the threefold differential cross section $dσ/(dM_{πΣ}dΩ_{p_n})$ for the $K^- d \to πΣn$ reaction below the $\bar K N$ threshold can be used to test the predictions of the resonance poles associated with $Λ(1405)$. We also find that the momentum dependence of the threefold differential cross sections for the $K^- d \to π^- Λp$ reaction can be used to examine the existence of a low-lying $J^P=1/2^+$ $Σ$ resonance with a pole mass $M_R = 1457 -i39$ MeV, which was found from analyzing the $K^-p$ reaction data within the employed DCC model.

nucl-th↗

arXiv2016

Nucleon resonance structure in the finite volume of lattice QCD

An approach for relating the nucleon resonances extracted from $πN$ reaction data to lattice QCD calculations has been developed by using the finite-volume Hamiltonian method. Within models of $πN$ reactions, bare states are introduced to parametrize the intrinsic excitations of the nucleon. We show that the resonance pole positions can be related to the probability $P_{N^*}(E)$ of finding the bare state, $N^*$, in the $πN$ scattering states in infinite volume. We further demonstrate that the probability $P_{N^*}^V(E)$ of finding the same bare states in the eigenfunctions of the underlying Hamiltonian in finite volume approaches $P_{N^*}(E)$ as the volume increases. Our findings suggest that the comparison of $P_{N^*}(E)$ and $P_{N^*}^V(E)$ can be used to examine whether the nucleon resonances extracted from the $πN$ reaction data within the dynamical models are consistent with lattice QCD calculation. We also discuss the measurement of $P_{N^*}^V(E)$ directly from lattice QCD. The practical differences between our approach and the approach using the Lüscher formalism to relate LQCD calculations to the nucleon resonance poles embedded in the data are also discussed.

hep-lat↗

arXiv2016

Isospin decomposition of the $γ^{()} N \to N^$ transitions as input for constructing models of neutrino-induced reactions in the nucleon resonance region

We present our recent efforts to determine the matrix elements associated with the transition between the nucleon and a nucleon resonance induced by the vector current, which are necessary ingredients for models of neutrino-induced reactions in the resonance region. This is accomplished by making the comprehensive analysis of the data for various meson photo- and electro-production reactions off the nucleon within a sophisticated coupled-channels framework, which is known as the ANL-Osaka dynamical coupled-channels model. We also give a brief introduction to our project for constructing a unified neutrino reaction model conducted at the J-PARC Branch of the KEK Theory Center.

nucl-th↗

arXiv2016

Isospin decomposition of $γN \to N^*$ transitions within a dynamical coupled-channels model

By extending the dynamical coupled-channels analysis performed in our previous work [Phys. Rev. C 88, 035209 (2013)] to include the available data of photoproduction of pi meson off the neutron, the transition amplitudes for the photo-excitation of the neutron to nucleon resonances, gamma n --> N*, at the resonance pole positions are determined. The combined fits to the data for both the proton- and neutron-target reactions also revise our results for the resonance pole positions and the gamma p --> N* transition amplitudes. Our results allow an isospin decomposition of the gamma N --> N* transition amplitudes for the isospin I=1/2 N* resonances, which is necessary for testing hadron structure models and gives crucial inputs for constructing models of neutrino-induced reactions in the nucleon resonance region.

nucl-th↗