Related papers: The Roper resonance and kin
Our recently proposed model of the $\Delta(1600)$ resonance, in which the dominant component is a quasi-bound state of the $\Delta(1232)$ and the pion, is confronted with a similar model of the $N^*(1440)$ resonance as its counterpart in…
A parameter-free evaluation of the $N - P_{11}(1440)$ electromagnetic transition form factors is performed within a light-front constituent quark model, using for the first time the eigenfunctions of a mass operator which generates a large…
We derive a method to calculate the multi-channel K matrix applicable to a broad class of models in which mesons linearly couple to the quark core. The method is used to calculate pion scattering amplitudes in the energy region of low-lying…
The relativistic three-quark equations are found in the framework of the dispersion relation technique. The approximate solutions of these equations using the method based on the extraction of leading singularities of the amplitude are…
We study the Roper excitation in the $(\alpha,\alpha')$ reaction. We consider all processes which may be relevant in the Roper excitation region, namely, Roper excitation in the target, Roper excitation in the projectile, and double…
We derive the long-range components of the nucleon-nucleon (NN) two-pion-exchange potential with an intermediate Roper resonance. Leading-order interactions in heavy-baryon chiral perturbation theory are considered. NN phase shifts with…
We report our recent work on a hadronic molecule state of the KbarKN system with I=1/2 and J^P=1/2^+. We assume that the Lambda(1405) resonance and the scalar mesons, f_{0}(980), a_{0}(980), are reproduced as quasi-bound states of KbarN and…
Exclusive measurements of the quasi-free $pn \to pp\pi^-$ and $pp \to pp\pi^0$ reactions have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have…
There exists experimental evidence that a dibaryon resonance d' with quantum numbers J^P=0^-,T=0 and mass 2065 MeV could be the origin of the narrow peak in the (\pi^+ ,\pi^- ) double charge exchange cross--sections on nuclei. We…
We calculate the decays of baryon resonances to the pion + Roper resonance channel in the frame of the flux-tube breaking model. The baryon and meson wavefunctions we use are obtained from a linear confinement semi-relativistic constituent…
A nearest-neighbor analysis of light flavor baryon mass spectra reveals striking degeneracy patterns- narrow mass bands populated by series of parity twins of steadily increasing spins. Each series terminates by an unpaired resonance of the…
The electroexcitation amplitudes or $\gamma_vpN^*$ electrocouplings of the $N(1440)1/2^+$, $N(1520)3/2^-$, and $\Delta(1600)3/2^+$ resonances were obtained for the first time from the $ep \to e'\pi^+\pi^-p'$ differential cross sections…
A nucleon resonance with spin-parity $J^P=3/2^-$ and mass about 2.1 GeV is essential to reproduce the photoproduction cross sections for $\Lambda(1520)$ released by the LEPS and CLAS Collaborations. It can be explained as the third nucleon…
In this talk I summarize recent findings around the description of axial vector mesons as dynamically generated states from the interaction of pseudoscalar mesons and vector mesons, dedicating some attention to the two $K_1(1270)$ states.…
The interaction potentials between vector mesons and octet baryons are calculated explicitly with a summation of t-, s-, u-channel diagrams and a contact term originating from the tensor interaction. Many resonances are generated…
We study the coupling of the Lambda(1520)= Lambda* resonance to the \bar K* vector meson and nucleon. This coupling is not directly measured from the resonance decay, but is expected to be important in hyperon production reactions, in…
Quenched and unquenched quark models predict very different patterns for the spectrum of the low excited hyperon states. Evidence is accumulating for the existence of some new hyperon resonances, such as a $\Sigma^*$ of spin-parity…
We study the masses and wave functions of heavy-light quark-antiquark system in the relativistic potential model, where we focus on the higher excited states of $B$ and $D$ mesons. The resonances of $D_J(2740)$, $D_J^*(2760)$, $D_J^*(3000)$…
We study the ground and first excited states of nucleons in a chiral quark-diquark model. We include two quark-diquark channels of the scalar-isoscalar and axial-vector-isovector types for the nucleon states. The diquark correlation…
Identifying the Roper N(1440) and N(1710) as the pentaquark octet and anti-decuplet, respectively, we analyze their main decay modes in the diquark picture. The ratio of the partial decay widths is largely consistent with the nearly ideal…