Isospin and Spin-Isospin Modes in Charge-Exchange Reactions

Conference · Thu Dec 30 23:00:00 EST 1999

OSTI ID:784429

Harakeh, M N; Akimune, H; van den Berg, A M; Brandenburg, S; Fujiwara, M; Laurent, H; Willis, A; Zegers, R G.T.

The microscopic structure of the Gamow-Teller resonance (GTR) and spin-dipole resonance (SDR) in {sup 208}Bi has been investigated in the {sup 208}Pb({sup 3}He,tp){sup 207}Pb reaction at E{sup 3}He=450 MeV and very forward scattering angles. The partial and total branching ratios and the escape widths for GTR and SDR decay to the residual neutron-hole states in {sup 207}Pb were deduced. These are found to be in good agreement with recent theoretical estimates. The ({sup 3}He,tp) reaction on Pb at E({sup 3}He)=177 MeV was also studied in order to locate isovector monopole strength corresponding to 2{Dirac_h}{omega} transitions. Monopole strength at excitation energies above 25 MeV was discovered and compared to calculated strength due to the isovector giant monopole resonance and the spin-flip isovector monopole resonance. Calculations in a normal-mode framework show that all isovector monopole strength can be accounted for if the branching ratio for decay by proton emission is 20%.

• Research Organization: Kernfysisch Versneller Instituut, Groningen (NL); Research Center for Nuclear Physics, Osaka University, Osaka (JP); Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki (JP); Institut de Physique Nucleaire, Universite de Paris-Sud, Orsay Cedez (FR)
• Sponsoring Organization: Nederlandse Organisatie voor Wetenschappelijk Onderzoek (US)
• OSTI ID: 784429
• Report Number(s): None; ISBN 1-56396-907-6; ISSN 0094-243X; CODEN APCPCS; ISBN 1-56396-907-6; ISSN 0094-243X; CODEN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BISMUTH 208
BRANCHING RATIO
CHARGE-EXCHANGE REACTIONS
COINCIDENCE SPECTROMETRY
DIFFERENTIAL CROSS SECTIONS
ENERGY LEVELS
GAMOW-TELLER RULES
GIANT RESONANCE
HELIUM 3 REACTIONS
ISOSPIN
LEAD 207
LEAD 208 TARGET
LEVEL WIDTHS
MEV RANGE 100-1000
MONOPOLES
PROTONS
SPIN FLIP
TRITONS