Related papers: Isolating the Roper Resonance in Lattice QCD
The mass of the lightest hadron in nature, the pion, is one seventh of that of the nucleon, and one tenth of the mass of its first excited state, the $\pi(1300)$. This enormous energy difference opens an interesting window into the…
In this work we present the isovector flavor combination for the nucleon tensor charge extracted from lattice QCD simulations using overlap fermions on $N_f=2+1$ domain-wall configurations. The pion mass dependence is studied using six…
We investigate the mass of the parity partner $N^* (1/2^{-})$ of the nucleon $N(1/2^{+})$, in lattice QCD using a new lattice discretization scheme for fermions, domain wall fermions (DWF). DWF possess exact chiral symmetry and flavor…
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 study spin $\frac12$ hadronic states in quenched lattice QCD to search for a possible $S=+1$ pentaquark resonance. Our work is the first systematic lattice QCD study which properly carries out the following analyses: {\it (1) the careful…
The amplitudes of the transition gamma* N -> P11(1440) are calculated within light-front relativistic quark model assuming that the P11(1440) is the first radial excitation of the 3q ground state. The results are presented along with the…
The Roper state is described in the framework of the chiral chromodielectric model as a single quark excitation in self-consistent meson potentials. The interplay between quark and meson excitations is discussed and we emphasise the role of…
The calculation of the light-hadron spectrum in the quenched approximation to QCD using an anisotropic clover fermion action is presented. The tuning of the parameters of the action is discussed, using the pion and rho dispersion relation.…
We study one pion emission decay of the first excited state of the nucleon with negative parity $N(1535) \equiv N^*$ in the holographic model of QCD. The excited state is described as a vibrational mode along the extra $z$ direction in the…
In many reactions leading to excitations of the nucleon the Roper resonance $N^*(1440)$ can be sensed only by complex partial-wave analyses. In nucleon-nucleon collisions the isoscalar single-pion production as well as specific two-pion…
The helicity amplitudes of the electroexcitation of the Roper resonance on proton are extracted at 1.7 < Q2 < 4.2 GeV2 from recent high precision JLab-CLAS cross sections data and longitudinally polarized beam asymmetry for pi+…
The second excitation of the nucleon, the Roper, has properties differentiated from other low-lying nucleon resonances. Their properties challenge our understanding of the structure of the baryons in terms of the degrees of freedom from…
A relativistic light-front quark model is used to describe both the elastic nucleon and nucleon-Roper transition form factors in a large Q2 range, up to 35 GeV2 for the elastic and up to 12 GeV2 for the resonance case. Relativistic…
We study the three-body decay of the newly observed bottom baryon $\Lambda_b^*(6072)$ by LHCb; $\Lambda_b^*(6072) \to \Lambda_b \pi \pi$. Its mass about 500 MeV above the ground state $\Lambda_b$ and a broad width imply that the state could…
The excitation spectrum of the nucleon with the spin 1/2 is examined by using the Friedberg-Lee model containing the constituent quark and the scalar meson. An appropriate way of quantization for the non-linear meson field is employed by…
The lower excitation spectrum of the nucleon and $\Delta$ is calculated in a relativistic chiral quark model. Contributions of the second order self-energy and exchange diagrams due-to pion fields to the mass spectrum of the SU(2) baryons…
We compute the axial, scalar, tensor and pseudoscalar isovector couplings of the nucleon as well as the induced tensor and pseudoscalar charges in lattice simulations with $N_f=2$ mass-degenerate non-perturbatively improved…
We study the pion-nucleon system in s-wave in the framework of lattice QCD in order to gain new information on the nucleon excited states. We perform simulations for $n_f =2$ mass degenerate light quarks at a pion mass of 266 MeV. The…
Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the…
We investigate the structure of the nucleon resonance N^*(1440) (Roper) within a coupled-channel meson exchange model for pion-nucleon scattering. The coupling to pipiN states is realized effectively by the coupling to the sigmaN, piDelta…