A New Spectroscopic Tool by the Radioactive-Isotope-Beam Induced Exothermic Charge-Exchange Reaction
- Shumpei Noji, NSCL
Thursday, May 3, 11:00 AM - Research Discussion
NSCL Lecture Hall
Charge-exchange reactions induced by radioactive heavy-ions have potentiality for studies of a variety of spin-isospin responses due to their unique reaction kinematics and selectivities. Among them the (12N,12C) reaction has peculiar features: This reaction can be exothermic (Q > 0) owing to the large mass difference of about 17 MeV between the 12N projectile and the 12C ejectile, and accordingly it can realize small momentum transfer even for highly-excited states. Moreover, since the final state in the 12C ejective can be identified by detecting the de-excitation gamma rays, the excitation modes with the transferred quantum numbers (S = 1, T = 1) and (S = 0, T = 1) can be selected. These features make this reaction suitable for the study of yet-to-be-discovered states such as the isovector spin monopole resonance (IVSMR). We performed for the first time an experiment of this exothermic charge-exchange (12N,12C) reaction on a 90Zr target at an incident energy of 175 MeV/u at the RI Beam Factory (RIBF) at RIKEN using the magnetic spectrometer SHARAQ and the gamma-ray detector array DALI2, and observed the isovector spin monopole strength in 90Nb. In this research discussion, I will present the details of the experiment and discuss the results.