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The recent BESIII data on $J/ψ\toγ(K_SK_Sπ^0)$, which is significantly more precise than earlier $η(1405/1475)$-related data, enables quantitative discussions on $η(1405/1475)$ at the previously unreachable level. We conduct a three-body unitary coupled-channel analysis of experimental Monte-Carlo outputs for radiative $J/ψ$ decays via $η(1405/1475)$: $K_SK_Sπ^0$ Dalitz plot distributions from the BESIII, and branching ratios of $γ(ηπ^+π^-)$ and $γ(γπ^+π^-)$ final states relative to that of $γ(K\bar{K}π)$. Our model systematically considers (multi-)loop diagrams and an associated triangle singularity, which is critical in making excellent predictions on $η(1405/1475)\to πππ$ lineshapes and branching ratios. The $η(1405/1475)$ pole locations are revealed for the first time. Two poles for $η(1405)$ are found on different Riemann sheets of the $K^*\bar{K}$ channel, while one pole for $η(1475)$. The $η(1405/1475)$ states are described with two bare states dressed by continuum states. The lower bare state would be an excited $η^\prime$, while the higher one could be an excited $η^{(\prime)}$, hybrid, glueball, or their mixture. This work presents the first-ever pole determination based on a manifestly three-body unitary coupled-channel framework applied to experimental three-body final state distributions (Dalitz plots)., 7 pages, 6 figures; (v2) published version; statistical errors for eta(1405/1475) pole positions are added

First hidden-charm pentaquark candidate with strangeness, $P_{ψs}^Λ(4338)$, was recently discovered in $B^-\to J/ψΛ\bar{p}$ by the LHCb Collaboration. $P_{ψs}^Λ(4338)$ shows up as a bump at the $Ξ_c\bar{D}$ threshold in the $J/ψΛ$ invariant mass ($M_{J/ψΛ}$) distribution. The $M_{J/ψΛ}$ distribution also shows a large fluctuation at the $Λ_c\bar{D}_s$ threshold, hinting the existence of a possible $P_{ψs}^Λ(4255)$. In this work, we determine the $P_{ψs}^Λ(4338)$ and $P_{ψs}^Λ(4255)$ pole positions for the first time. For this purpose, we fit a $B^-\to J/ψΛ\bar{p}$ model to the $M_{J/ψΛ}$, $M_{J/ψ\bar{p}}$, $M_{Λ\bar{p}}$, and $\cosθ_{K^*}$ distributions from the LHCb simultaneously; $χ^2/{\rm ndf}\sim 1.21$. Then we extract $P_{ψs}^Λ$ poles from a unitary $Ξ_c\bar{D}$-$Λ_c\bar{D}_s$ coupled-channel scattering amplitude built in the model. In our default fit, the $P_{ψs}^Λ(4338)$ pole is found at $( 4338.2\pm 1.4)-( 1.9\pm 0.5 )\,i$ MeV while the $P_{ψs}^Λ(4255)$ pole at $4254.7\pm 0.4$ MeV. The $P_{ψs}^Λ(4338)$ and $P_{ψs}^Λ(4255)$ are mostly $Ξ_c \bar{D}$ bound and $Λ_c\bar{D}_s$ virtual states, respectively. Through our analysis, the data disfavors a hypothesis of $P_{ψs}^Λ(4338)$ as merely a kinematical effect. This pole determination, which is important in its own right, sets a primary basis to study the nature of the $P_{ψs}^Λ$ states., 8 pages, 5 figures, 3 tables; (v2) statistical errors of pole values corrected; (v3) efficiency-corrected and background-subtracted data are analyzed; a figure of Dalitz plot distribution added; (v4) published version

The recent LHCb data on $B_s^0\to J/��p\bar{p}$ revealed a new pentaquark-like $P_c(4337)^+$ structure, while finding no evidence for $P_c(4312)^+$ discovered earlier in $��_b^0\to J/��p K^-$. Though puzzling, the data actually offer an important hint to understand the nature of the pentaquark candidates. We develop a model to analyze the $B_s^0\to J/��p\bar{p}$ data. We find that a $��_c\bar{D}$ one-loop mechanism causes a threshold cusp that fits well the $P_c(4337)^+$ peak. Also, the $��_c\bar{D}$ and $��_c\bar{D}^{*}$ threshold cusps interfere with each other to reproduce an oscillating behavior in the proton helicity angle distribution. These results combined with our earlier analysis on $��_b^0\to J/��p K^-$ indicate that $P_c(4312)^+$ and $P_c(4337)^+$ are created by different interference patterns between the $��_c\bar{D}$ and $��_c\bar{D}^{*}$ (anomalous) threshold cusps. The proposed scenario consistently explains why the $P_c(4312)^+$ and $P_c(4337)^+$ peaks appear in $��_b^0\to J/��p K^-$ and $B_s^0\to J/��p\bar{p}$, respectively, but not vice versa or both., 7 pages, 4 figures; (v2) published version, title changed, one paragraph added in Sec. 2, references added

$Z_c(4430)$ discovered by the Belle and confirmed by the LHCb in $\bar{B}^0\to\psi(2S)K^-\pi^+$ is generally considered to be a charged charmonium-like state that includes minimally two quarks and two antiquarks. $Z_c(4200)$ found in $\bar{B}^0\to J/\psi K^-\pi^+$ by the Belle is also a good candidate of a charged charmonium-like state. We demonstrate that kinematical singularities in triangle loop diagrams induce a resonance-like behavior that can consistently explain the properties (mass, width, and Argand plot) of $Z_c(4430)$ and $Z_c(4200)$ from the experimental analyses. The triangle diagrams include only experimentally well-established hadrons. Applying this idea to $\Lambda_b^0\to J/\psi p\pi^-$, we also identify triangle singularities that behave like $Z_c(4200)$, but no triangle diagram is available for $Z_c(4430)$. This is consistent with the LHCb's finding that their description of the $\Lambda_b^0\to J/\psi p\pi^-$ data is significantly improved by including a $Z_c(4200)$ contribution while $Z_c(4430)$ seems to hardly contribute. Even though the proposed mechanisms have uncertainty in the absolute strengths which are currently difficult to estimate, they are certainly a compelling alternative to tetraquark-based interpretations of $Z_c(4430)$ and $Z_c(4200)$., Comment: 6 pages, 5 figures; published version; one figure on the cutoff-dependence added

The NuSTEC workshop (https://indico.cern.ch/event/727283) held at L'Aquila in October 2018 was devoted to neutrino-nucleus scattering in the kinematic region where hadronic systems with invariant masses above the $\Delta(1232)$ resonance are produced: the so-called shallow- and deep-inelastic scattering regime. Not only is the physics in this kinematic region quite intriguing, it is also important for current and future oscillation experiments with accelerator and atmospheric neutrinos. For the benefit of the community, links to the presentations are accompanied by annotations from the speakers., Comment: Proceedings of "NuSTEC workshop of Neutrino-Nucleus Scattering in the Shallow- and Deep-Inelastic Kinematic regime", GSSI, L'Aquila, Italy on October 11-13, 2018. 31 pages, 24 talk links

The determination of the Argonne National Laboratory-Osaka University (ANL-Osaka) Partial-Wave Amplitudes (PWA) of $��N$ and $��N$ 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 $MB, M'B'= ��N, ��N, K��, K��$, (2) two-pion production $��N \rightarrow ����, ��N, ��N \rightarrow ����N$, (3) Meson photoproduction $��N \rightarrow ��N, ��N, K��, K��$, (4) Pion electroproduction $N(e,e'��)N$, (5) inclusive $N(e,e')X$. We also present sample results from our fits to the data., 55 pages, 33 figures; minor typos corrected

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 $d(\gamma,\pi)NN$ 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 $\Delta$(1232) resonance, and are still significant at higher energies. The results are in good agreement with most of the available data of $d(\gamma,\pi^0)np$ and $d(\gamma,\pi^-)pp$ reactions., Comment: 22 pages, 12 figures, title changed, website for ANL-Osaka amplitudes added, section for extracting neutron-target observables removed

We study $��$ photoproduction off the deuteron ($��d\to��pn$) at a special kinematics: $\sim 0.94$ GeV of the photon beam energy and $\sim 0^\circ$ of the scattering angle of the proton. This kinematics is ideal to extract the low-energy $��$-nucleon scattering parameters such as $a_{��N}$ (scattering length) and $r_{��N}$ (effective range) because the $��$-nucleon elastic scattering is significantly enhanced. We show that if a ratio $R$, the $��d\to��pn$ cross section divided by the $��p\to��p$ cross section convoluted with the proton momentum distribution in the deuteron, is measured with 5% error, ${\rm Re}[a_{��N}]$ (${\rm Re}[r_{��N}]$) can be determined at the precision of $\sim\pm$0.1 fm ($\sim\pm$0.5 fm), significantly narrowing down the currently estimated range of the parameters. The measurement is ongoing at the Research Center for Electron Photon Science (ELPH), Tohoku University., 4 pages, 5 figures, Contribution to the Proceedings for 8th International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Japan

We develop a reaction model for $��$ photoproduction off the deuteron ($��d\to��pn$), and study the reaction at a special kinematics, where the photon beam energy is $\sim 0.94$ GeV and the scattered proton is detected at $\sim 0^\circ$, for the purpose of determining the $��$-nucleon scattering length ($a_{��N}$) and effective range ($r_{��N}$). In this kinematics, the $��$-nucleon elastic rescattering is significantly enhanced while other background mechanisms being suppressed. We show that a ratio $R$, the $��d\to��pn$ cross section divided by the $��p\to��p$ cross section convoluted with the proton momentum distribution in the deuteron, has a very good resolving power of $a_{��N}$ and $r_{��N}$. We conclude that the $R$ data with 5% error, binned in 1 MeV width of the $��$-neutron invariant mass, can determine ${\rm Re}[a_{��N}]$ (${\rm Re}[r_{��N}]$) at the precision of $\sim\pm$0.1 fm ($\sim\pm$0.5 fm), significantly narrowing down the previously estimated ranges of the parameters. To arrive at the conclusion, it is essential to use the $��d\to��pn$ reaction model equipped with elementary amplitudes that are well constrained by $��N$ and $��N$ reaction data through a sophisticated coupled-channels analysis. This result strongly motivates the Research Center for Electron Photon Science (ELPH) at Tohoku University to measure $R$., 6 pages, 6 figures, published version, 1 figure added, several references added, discussion on the previous works elaborated

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., 6 pages, 3 figures. Contribution to the proceedings of 18th International Workshop on Neutrino Factories and Future Neutrino Facilities Search (NuFact16), Quy Nhon, Vietnam, August 21-27, 2016

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., 20 pages, 12 figures. Typos, equations, and numerical values in Tables are corrected

Resonance parameters (pole masses and residues) associated with the excited states of hyperons, Lambda^* and Sigma^*, are extracted within a dynamical coupled-channels model developed recently by us [Phys. Rev. C 90, 065204 (2014)] through a comprehensive partial-wave analysis of the K^- p --> barK N, pi Sigma, pi Lambda, eta Lambda, K Xi data up to invariant mass W = 2.1 GeV. We confirm the existence of resonances corresponding to most, if not all, of the four-star resonances rated by the Particle Data Group. We also find several new resonances, and in particular propose a possible existence of a new narrow J^P=3/2^+ Lambda resonance that couples strongly to the eta Lambda channel. The J^P=1/2^- Lambda resonances located below the barK N threshold are also discussed. Comparing our extracted pole masses with the ones from a recent analysis by the Kent State University group, some significant differences in the extracted resonance parameters are found, suggesting the need of more extensive and accurate data of K^- p reactions including polarization observables to eliminate such an analysis dependence of the resonance parameters. In addition, the determined large branching ratios of the decays of high-mass resonances to the pi Sigma^* and barK^* N channels also suggest the importance of the data of 2 --> 3 reactions such as K^- p --> pi pi Lambda and K^- p --> pi barK N. Experiments on measuring cross sections and polarization observables of these fundamental reactions are highly desirable at hadron beam facilities such as J-PARC for establishing the Lambda^* and Sigma^* spectrum., 25 pages, 8 figures. Version to appear in Physical Review C

We report our recent effort on the extraction of N*- and Delta*-resonance parameters (pole masses, coupling constants, etc.) through the comprehensive analysis of pion- and photon-induced pi N, eta N, K Lambda, and K Sigma production reactions. The analysis was performed with the ANL-Osaka dynamical coupled-channels approach, which satisfies the multichannel unitarity of the S-matrix in the channel space spanned by pi N, eta N, K Lambda, K Sigma, and also three-body pi pi N that contains rho N, pi Delta, and sigma N resonant components. Ongoing projects and future plans are also discussed., 5 pages, 4 figures. Contribution to the proceedings of 15th International Conference on Hadron Spectroscopy -- HADRON2013, November 4-8, 2013, Nara, Japan

We study neutrino-induced meson productions off the nucleon in the forward limit by applying the PCAC hypothesis to our dynamical coupled-channels (DCC) model. The DCC model reasonably describes pi N, gamma N -> pi N, eta N, K Lambda, K Sigma data in the resonance region. We give a prediction for nu N -> pi N, pi pi N, eta N, K Lambda, K Sigma$ reactions cross sections. We compare our results with those from the Rein-Sehgal model, and find a significant difference., 4 pages, 3 figures, Contribution to the proceedings of International Workshop on Neutrino Factories, Super Beams and Beta Beams (NUFACT 2013), August 19-24 2013, Beijing, China

The nucleon resonances are investigated within a dynamical coupled-channels model of pi N and gamma N reactions up to the invariant mass W = 2 GeV. The meson-baryon (MB) channels included in the calculations are MB = pi N, eta N, K Lambda, K Sigma, and pi pi N that has pi Delta, rho N, and sigma N resonant components. The meson-baryon amplitudes T_{M'B',MB}(W) are calculated from solving a set of coupled-channels integral equations defined by an interaction Hamiltonian consisting of (a) meson-exchange interactions v_{M'B',MB} derived from phenomenological Lagrangian, and (b) vertex interactions N* --> MB for describing the transition of a bare excited nucleon state N* to a channel MB. The parameters of v_{M'B',MB} are mainly constrained by the fit to the data of pi N --> pi N in the low energy region up to W =1.4 GeV. The bare masses of N* and the N* --> MB parameters are then determined in simultaneous fits to the data of pi N --> pi N up to W =2.3 GeV and those of pi N --> eta N, K Lambda, K Sigma and gamma N --> pi N, eta N, K Lambda, K Sigma up to W = 2.1 GeV. The pole positions and residues of nucleon resonances are extracted by analytically continuing the meson-baryon amplitudes T_{M'B',MB}(W) to the complex Riemann energy surface. From the extracted residues, we have determined the N* --> pi N, gamma N, eta N, K Lambda, K Sigma transition amplitudes at resonance poles. We compare the resonance pole positions from our analysis with those given by Particle Data Group and the recent coupled-channels analyses by the Juelich and Bonn-Gatchina groups. Four results agree well only for the first N* in each spin-parity-isospin (J^P,I) channel. For higher mass states, the number of states and their resonance positions from four results do not agree well. We discuss the possible sources of the discrepancies and the need of additional data from new hadron facilities such as J-PARC., 83 pages, 47 figures. Typos are corrected and references are added. Version to appear in PRC

We address a question about how much resonance poles and residues extracted from data depend on a model used for the extraction, and on the precision of data. We focus on the P11 pi-N scattering and use the dynamical coupled-channel (DCC) model developed in Excited Baryon Analysis Center (EBAC) at JLab. We examine the model-dependence of the poles by varying parameters largely within the EBAC-DCC model. We find that two poles associated with the Roper resonance are fairly stable against the variation. We also study the stability of the Roper poles against different analytic structure of the P11 amplitude below pi-N threshold by using a bare nucleon model. We again find a good stability of the Roper poles., 4 pages, 4 figures, Contribution to the proceedings of 12th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU2010), Williamsburg, USA, May 31-June 4 2010

We show that two P11 nucleon resonance poles near the pi Delta threshold, obtained in several analyses, are stable against large variations of parameters within a dynamical coupled-channels analysis based on meson-exchange mechanisms. By also performing an analysis based on a model with a bare nucleon state, we find that this two-pole structure is insensitive to the analytic structure of the amplitude in the region below pi N threshold. Our results are M_pole = (1363^{+9}_{-6} -i79^{+3}_{-5}) MeV and (1373^{+12}_{-10} -i114^{+14}_{-9}) MeV. We also demonstrate that the number of poles in the 1.5 GeV < W < 2 GeV region could be more than one, depending on how the structure of the single-energy solution of SAID is fitted. For three-pole solutions, our best estimated result of a pole near N(1710) listed by Particle Data Group is (1829^{+131}_{-65} -i192^{+88}_{-110}) MeV which is close to the results of several previous analyses. Our results indicate the need of more accurate pi N reaction data in the W > 1.6 GeV region for high precision resonance extractions., 15 pages, 4 figures

We study coherent pion production in neutrino-nucleus scattering in the energy region relevant to the recent neutrino oscillation experiments. Our approach is based on the combined use of the Sato-Lee model and the Delta-hole model. Our initial numerical results are compared with the recent data from K2K and SciBooNE., Comment: 3 pages, 2 figures, To appear in the proceedings of the 18th Particle and Nuclei International Conference (PANIC08), Eilat, Israel, 9-14 Nov 2008; acknowledgment added