Electroexcitation of nucleon resonances at Q^2=0.65 GeV/c^2 from a combined analysis of single- and double-pion electroproduction data

Data on single- and double-charged pion electroproduction off protons are successfully described in the second and third nucleon resonance regions with common N* photocouplings. The analysis was carried out using separate isobar models for both reactions. From the combined analysis of two exclusive channels, the gamma* p --> N*+ helicity amplitudes are obtained for the resonances P11(1440), D13(1520), S31(1620), S11(1650), F15(1680), D33(1700), D13(1700), and P13(1720) at Q2=0.65 GeV/c^2.Comment: 12 pages, 12 figures (eps), Published in PHYSICAL REVIEW C 72, 045201 (2005

Phenomenological analysis of the CLAS data on double charged pion photo and electro- production

First comprehensive data on the evolution of nucleon resonance photocouplings with photon virtuality Q^2 are presented for excited proton states in the mass range from 1.4 to 2.0 GeV. N^* photocouplings were determined in phenomenological analysis of CLAS data on 2 pi photo and electroproduction within the framework of the JLAB-MSU phenomenological model.Comment: 10 pages, 7 figures (encapsulated postscript

Nucleon Resonance Structure from CLAS and CLAS12 Experiments

The recent results on the photo- and electrocouplings extraction from the reaction of one- and two-pion photo- and electroproduction off protons in the resonances region are presented. The production of two charged pions is of particular importance for evaluation of the photocouplings for the Δ(1620)12 −, Δ(1700)32 −

Examination of the astrophysical S-factors of the radiative proton capture on 2H, 6Li, 7Li, 12C and 13C

Astrophysical S-factors of radiative capture reactions on light nuclei have been calculated in a two-cluster potential model, taking into account the separation of orbital states by the use of Young schemes. The local two-body potentials describing the interaction of the clusters were determined by fitting scattering data and properties of bound states. The many-body character of the problem is approximatively accounted for by Pauli forbidden states. An important feature of the approach is the consideration of the dependence of the interaction potential between the clusters on the orbital Young schemes, which determine the permutation symmetry of the nucleon system. Proton capture on 2H, 6Li, 7Li, 12C, and 13C was analyzed in this approach. Experimental data at low energies were described reasonably well when the phase shifts for cluster-cluster scattering, extracted from precise data, were used. This shows that decreasing the experimental error on differential elastic scattering cross sections of light nuclei at astrophysical energies is very important also to allow a more accurate phase shift analysis. A future increase in precision will allow more definite conclusions regarding the reaction mechanisms and astrophysical conditions of thermonuclear reactions.Comment: 40p., 9 fig., 83 ref. arXiv admin note: substantial text overlap with arXiv:1005.1794, arXiv:1112.1760, arXiv:1005.198