Valence proton-neutron interactions throughout the mass surface
- Clark University, Worcester, Massachusetts 01610 (United States)
- Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States)
Empirical average proton-neutron interaction energies, {delta}V{sub pn}, between the last nucleons can be isolated using double differences of masses. We have examined the systematic behavior of {delta}V{sub pn} throughout the mass surface using the 2003 mass table that includes many new and improved experimental masses. The results are especially revealing for self-conjugate nuclei and in regions of strong shell closures in heavy nuclei. In the former the large p-n interaction strength can be interpreted as a consequence of the T=0 interaction between protons and neutrons in spatially similar orbitals. In the latter, the bifurcated systematic can be understood in terms of the evolution of proton and neutron orbital overlaps in regions surrounding a shell closure. In regions between shells, anomalies are sometimes encountered that are not fully understood. They might reflect structural effects or could arise from one or more erroneously measured masses. A scheme based on fractional shell filling is presented that may serve as a signature of shell structure in exotic nuclei. A link between empirical p-n interactions and growth rates of collectivity is pointed out. Finally, our analysis is used to identify candidates for future mass measurements and their needed levels of accuracy, many of which will require new exotic beam facilities.
- OSTI ID:
- 20771338
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 73, Issue 3; Other Information: DOI: 10.1103/PhysRevC.73.034315; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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