Related papers: $N\pi$ scattering in the Roper channel

We present a lattice QCD calculation of the nucleon electric polarizabilities at the physical pion mass. Our findings reveal the substantial contributions of the $N\pi$ states to these polarizabilities. Without considering these…

We present a coupled-channel Lagrangian approach (GiM) to describe the $\pi N \to \pi N$, $2\pi N$ scattering in the resonance energy region. The $2\pi N$ production has been significantly improved by using the isobar approximation with…

A model for $\pi$N scattering and $\eta$-meson production in the S$_{11}$ channel is presented. The model includes $\pi$N-scattering Born terms as well as the N$^*${} resonances S$_{11}$(1535) and S$_{11}$(1610). The $T$-matrix is computed…

We employ a variational basis with a number of $\bar{q}q$ and $\pi\pi$ lattice interpolating fields with quantum numbers of the $\rho$ resonance to extract the discrete energy spectrum in a finite volume. In the elastic region, this…

Using the constrained curve fitting method and overlap fermions with the lowest pion mass at $180 {\rm MeV}$, we observe that the masses of the first positive and negative parity excited states of the nucleon tend to cross over as the quark…

As a first step to analyze the electromagnetic meson production reactions in the nucleon resonance region, the parameters of the hadronic interactions of a dynamical coupled-channel model, developed in {\it Physics Reports 439, 193 (2007)},…

We present the first lattice study of pion-pion scattering with varying number of colors, $N_\text{c}$. We use lattice simulations with four degenerate quark flavors, $N_\text{f}=4$, and $N_\text{c}=3-6$. We focus on two scattering channels…

We determine the $\Delta(1232)$ resonance parameters using lattice QCD and the L\"uscher method. The resonance occurs in elastic pion-nucleon scattering with $J^P=3/2^+$ in the isospin $I = 3/2$, $P$-wave channel. Our calculation is…

The positive-parity nucleon spectrum is explored in $2 + 1$-flavour lattice QCD in a search for new low-lying energy eigenstates near the energy regime of the Roper resonance. In addition to conventional three-quark operators, we consider…

We report the first lattice QCD study of the $s$-wave scattering of the $\bar{D}$-meson and the nucleon at the physical point, utilizing (2+1)-flavor configurations generated by the HAL QCD collaboration with a pion mass of $m_\pi\simeq…

We study excited states of the nucleon in quenched lattice QCD with the spectral analysis using the maximum entropy method. Our simulations are performed on three lattice sizes $16^3\times 32$, $24^3\times 32$ and $32^3\times 32$, at…

We give a pedagogical analysis on $K$ matrix models describing the $\pi N$ scattering amplitude, in $S_{11}$ channel at low energies. We show how the correct use of analyticity in the $s$ channel and crossing symmetry in $t$ and $u$…

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…

The positive-parity nucleon spectrum is studied in 2 + 1 flavour lattice QCD in an attempt to discover novel low-lying energy eigenstates in the region of the Roper resonance. In this work, we employ standard three-quark interpolating…

We report the first lattice QCD results of the scattering amplitudes of the $K\pi$ system for $I = 1/2$ channel together with $I=3/2$ case. We investigate all quark diagrams contributing to these iso-spin states, and find that the…

Scattering processes featuring the strong interactions can be studied using lattice QCD by means of the L\"uscher formalism. This approach relies on analyticity and unitarity of the $S$-matrix to relate infinite-volume scattering amplitudes…

First results on the interaction between the $\phi$-meson and the nucleon ($N$) are presented based on the ($2+1$)-flavor lattice QCD simulations with nearly physical quark masses. Using the HAL QCD method, the spacetime correlation of the…

We set up a general framework to describe $\pi\pi$ scattering below 1 GeV based on chiral low-energy expansion with possible spin-0 and 1 resonances. Partial wave amplitudes are obtained with the $N/D$ method, which satisfy unitarity,…

Extensive dynamical $N/D$ calculations are made in the study of $S_{11}$ channel low energy $\pi$N scatterings, based on various phenomenological model inputs of left cuts at tree level. The subtleties of the singular behavior of the…

The s-wave pion-pion ($\pi\pi$) scattering lengths are computed below the inelastic threshold by the L\"uscher technique with pion masses ranging from 240 MeV to 463 MeV. In the Asqtad-improved staggered fermion formulation, we calculate…