Related papers: Structure of hadron resonances with a nearby zero …
We study the origin of the resonances associated with pole singularities of the scattering amplitude in the chiral unitary approach. We propose a "natural renormalization" scheme using the low-energy interaction and the general principle of…
Castillejo-Dalitz-Dyson (CDD) poles are known to be connected with bound states and resonances. We discuss a new type of CDD pole associated with primitives i.e., poles of the P matrix that correspond to zeros of the D function on the…
We report on a recent theoretical work on the structure of the Lambda(1405) resonance within a chiral unitary approach, in which the resonance is dynamically generated in meson-baryon scattering. Studying the analytic structure of the…
In general, discrete eigenstates such as resonances are represented by poles of the scattering amplitude, analytically continued to the complex energy plane. In multi-channel scattering, however, the Riemann surface becomes more…
The mechanism for the formation of the $\Lambda(1405)$ resonance is studied in a chiral quark model that includes quark-meson as well as contact (four point) interactions. The negative-parity $S$-wave scattering amplitudes for strangeness…
This letter presents the first lattice QCD computation of the coupled channel $\pi\Sigma-\bar{K}N$ scattering amplitudes at energies near $1405\,{\rm MeV}$. These amplitudes contain the resonance $\Lambda(1405)$ with strangeness $S=-1$ and…
We study the compositeness of near-threshold states to clarify the internal structure of exotic hadron candidates. Within the framework of effective field theory, we extend the Weinberg's weak-binding relation to include the nearby CDD…
The paper concerns scattering of plane waves by a bounded obstacle with complex valued impedance boundary conditions. We study the spectrum of the Neumann-to-Dirichlet operator for small wave numbers and long wave asymptotic behavior of the…
In this paper we provide a detailed description of the eigenvalue $ E_{D}(x_0)\leq 0$ (respectively $ E_{N}(x_0)\leq 0$) of the self-adjoint Hamiltonian operator representing the negative Laplacian on the positive half-line with a Dirichlet…
We study the structure of two-body s-wave bound states as well as resonances in the threshold energy region. We focus on the single-channel scattering where the scattering length and the effective range are given by real numbers. It is…
We present the first calculation of coupled-channel meson-meson scattering in the isospin $=1$, $G$-parity negative sector, with channels $\pi \eta$, $K\overline{K}$ and $\pi \eta'$, in a first-principles approach to QCD. From the discrete…
In 2021, LHCb collaboration reported a very narrow state in the $D^0D^0\pi^+$ mass spectrum just below the $D^{*+}D^0$ mass threshold. We consider the influence of the Castillejo-Dalitz-Dyson (CDD) pole in the scattering amplitude to derive…
The pole structure of the $\Lambda(1405)$ is examined by fitting the couplings of an underlying Hamiltonian effective field theory to cross sections of $K^- p$ scattering in the infinite-volume limit. Finite-volume spectra are then obtained…
The analysis of the poles of the $\pi\pi$ scattering amplitude is shown to favour a dynamical origin of the sigma meson: it is created by a strongly attractive $\pi\pi$ interaction in the $J^{PC}=0^{++}I=0$ channel. In the limit…
We discuss the general behavior of the near-threshold scattering amplitude with channel couplings. The signal of the exotic hadrons near the threshold may manifest as a dip structure in the cross section originated from a zero point of the…
The analytic properties of scattering amplitudes provide important information. Besides the cuts, the poles and zeros on the different Riemann sheets determine the global behavior of the amplitude on the physical axis. Pole positions and…
In order to describe Lambda(1405) as a resonance in the baryon-meson scattering, we have investigated q^3-q qbar scattering system with the flavor-singlet q^3 (0s)^2(0p) state (the Lambda^1 pole). The scattering is treated by the quark…
The scattering length and effective range of the piSigma channel are studied in order to characterize the strangeness S=-1 meson-baryon scattering and the Lambda(1405) resonance. We examine various off-shell dependence of the amplitude in…
Using separable $NN$ and $\Lambda N$-$\Sigma N$ potentials in the Faddeev equations, we have demonstrated that the predicted enhancement in the $\Lambda d$ cross section near the $\Sigma d$ threshold is associated with resonance poles in…
Excited hadrons are seen as resonances in the scattering of lighter stable hadrons like $\pi$, $K$ and $\eta$. Many decay into multiple final states necessitating coupled-channel analyses. Recently it has become possible to obtain…