Δ Excitation in Nuclei by Heavy Ion Charge-Exchange Reactions
An extensive program on charge-exchange reactions is developed at Laboratoire National SATURNE. It consists of experiments on (3He,t), (d,2He) and heavy ion charge- exchange. In the incident energy domain around 1 GeV per nucleon, the spin-isospin modes are selectively excited. The spin-isospin response is concentrated in two excitation energy domains: — At low excitation energy, several particle-hole states contribute, the Gamow-Teller resonance and higher multipolarity spin-flip resonances. — Around 300 MeV, a nucleon from the target is excited into a Δ (1232) resonance. The strength in the Δ sector has the same order of magnitude as in the nuclear sector. In the case of Δ excitation, one π exchange is expected to be dominant and to induce collective or at least coherent attractive effects.
KeywordsIntegrate Cross Section Extreme Surface Niels Bohr Institute Short Range Contribution Nuclear Sector
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