0000000000335314
AUTHOR
H. J. Weber
RECENT DEVELOPMENTS INVOLVING ISOBARS IN NUCLEAR SYSTEMS — Workshop D
Developments of the last year or two concerning the role of isobar resonances in nuclear systems are reviewed. Special attention is given to the influence of the A isobar in the nucleon-nucleon force and to the possibility of the existence of NA or AA bound states. Also mentioned are the effects of the A in polarized pp scattering, in proton-nucleus scattering and in nuclear matter and the ground states of finite nuclei. Recent experiments intended to observe preexisting isobar configurations in nuclei are briefly surveyed. Approaches to pion-nucleus scattering based on NA interactions are discussed.
ElectromagneticN→N*(1535)transition in the relativistic constituent-quark model
We study a light-cone model of the nucleon and the ${S}_{11}(1535)$ resonance which provides a relativistic generalization of the constituent-quark model in the nonperturbative low-${Q}^{2}$ regime. The two parameters of the model, namely, the size parameter $\ensuremath{\alpha}$ and the constituent-quark mass ${m}_{q}\ensuremath{\approx}300$ MeV, are fixed by the axial form factor. We find good agreement for the electromagnetic form factors of the nucleon up to ${Q}^{2}\ensuremath{\approx}1\ensuremath{-}2$ Ge${\mathrm{V}}^{2}$. All static properties of the nucleon, except for the neutron charge radius, are reproduced within 10%. In addition, we show that the electromagnetic current of the …
Can relativistic pionic stripping explain (p,π+) reactions?
The relativistic pionic stripping formalism is used to study pion production data on $^{12}\mathrm{C}$ and $^{40}\mathrm{Ca}$ in order to determine the appropriate form of the pion-nucleon vertex and to determine whether pionic stripping is the dominant mechanism for pion production.
3,3 resonance and Nucleon pole model forpp→ppπ0 andpp→pnπ+
The Nucleon pole and 3,3 resonance pole contributions are considered for the reactionspp→ppπ0 andpp→pnπ+ at low and medium incident proton energies. The total and various differential cross sections are calculated, also for polarized nucleons, and compared with experimental data.