Alignment and decay of isobaric analog states formed by (p, n) reactions

Journal Article · Fri Oct 01 04:00:00 EDT 1976 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.14.1429· OSTI ID:7336891

Rao, G R; Austern, N

Calculations are presented here for the angular correlation between the neutron and proton in the reactions (p, np-bar) and (p, n..gamma..), where the (p, n) reaction excites the isobaric analog state (IAS) of the target ground state, which then decays by proton or ..gamma.. ray emission. The (p, n) reaction is treated as a charge-exchange direct reaction and calculations are done in the plane wave Born approximation, with a microscopic proton--nucleus interaction taken as a sum of two-body interactions. While the commonly used macroscopic charge-exchange interaction V/sub 0/(r) t x T is spherically symmetric, a microscopic interaction with individual nucleons allows higher multipole transfers and can lead to alignment of the IAS. The alignment of the IAS is sensitive to the relative importance of the higher multipole transfers that contribute to the formation of the IAS. The importance of these higher multipoles depends on the properties of the nucleon--nucleon interaction and also on the angle of neutron emission, which affects the momentum transfer. The alignment of the IAS can be inferred from the study of the decay channels of the IAS. For A greater that about 60, the IAS can decay by particle emission. Thus, the alignment of the IAS can be studied by the measurement of angular distributions of the decay protons in coincidence with the neutrons. Illustrative calculations of the alignment of the IAS and the angular distribution of decay protons are presented here for several nuclei; and comparisons with experimental measurements of n--p coincidence angular distributions for /sup 91/Zr and /sup 95/Mo are presented. The anisotropies in these two cases are weak. However, strong alignments of the IAS found theoretically for A < or approx. = 60 suggest that (p, n..gamma..) correlation experiments for those nuclei would be interesting. (AIP)

• Research Organization: University of Pittsburgh, Pittsburgh, Pennsylvania 15260
• OSTI ID: 7336891
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 14:4; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651715* -- Nuclear Properties &amp; Reactions
A=90-149
Theoretical-- Nuclear Reactions &amp; Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR CORRELATION
BARYON REACTIONS
BARYONS
BORN APPROXIMATION
CHARGE-EXCHANGE REACTIONS
CHARGED-PARTICLE REACTIONS
CORRELATIONS
DECAY
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EMISSION
ENERGY LEVELS
FERMIONS
GAMMA RADIATION
GAMMA SPECTRA
HADRON REACTIONS
HADRONS
IONIZING RADIATIONS
ISOBARIC ANALOGS
MOLYBDENUM 95 TARGET
NEUTRON EMISSION
NEUTRONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
PROTON REACTIONS
PROTONS
RADIATIONS
SPECTRA
TARGETS
ZIRCONIUM 91 TARGET