New double-magic nucleus {sup 96}Zr and conditions for existence of new magic nuclei
- Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)
New information about energies and occupation probabilities of neutron and proton single-particle (hole) subshells in even-even nuclei was obtained in previous studies applying the method of putting into correspondence all available data on one-nucleon pickup and stripping reactions. The most important and interesting result was identification of several nuclei as new magic ones. Namely, itwas found that a filling of the neutron 2d{sub 5/2} subshell in {sup 96}Zr makes this nuclide a magic one. Moreover, changes in proton subshell energies with increasing neutron number N are accompanied by an increasing energy gap between closed 2p{sub 1/2} and empty 1g{sub 9/2} subshells. Thus, the neutron number N = 56 appears to be a magic one if the proton number Z is equal to 40. The proton number Z = 40 manifests properties of the magic number in {sup 96}Zr. Therefore, {sup 96}Zr was identified as a new double-magic nucleus. Further investigations revealed that the energy of the first 2{sup +} state E(2{sub 1}{sup +}) in {sup 96}Zr is much higher than that in the neighboring isotopes and isotones, whereas the ratio E(4{sub 1}{sup +})/E(2{sub 1}{sup +}) and the quadrupole deformation parameter {beta}2 are, vice versa, clearly lower. Moreover, the A dependence of the neutron separation energy B(n) in Zr isotopes has an irregularity at N = 56 which is typical of magic nuclei. As a result of these investigations, it was found that, near the Fermi energy, there are two closed subshells with the same (and large) angular momentum j 5/2 (viz. {pi}1f{sub 5/2} and {nu}2d{sub 5/2}). We call this situation the jj connection. The magic numbers under discussion (Z = 40 and N = 56) are achieved at the points where both subshells are closed, and in addition, the closed subshell with j = 1/2, {pi}2p{sub 1/2}, occurs above the proton {pi}1f{sub 5/2} subshell. This looks like a result of some additional attractive proton-neutron interaction. It was found that application of this scheme (jj connection) to other subshells reveals several other new magic nuclei: {sup 54}Ca (closed {pi}1d{sub 3/2} and {nu}2p{sub 3/2} together with closed {nu}2p{sub 1/2}), {sup 30}S and {sup 30}Si (closed {pi}1d{sub 5/2} and {nu}1d{sub 5/2} together with closed ({pi}/{nu})2s{sub 1/2}), and {sup 14}O and {sup 14}C (closed {pi}1p{sub 3/2} and {nu}1p{sub 3/2} together with closed {nu}2p{sub 1/2})
- OSTI ID:
- 21075754
- Journal Information:
- Physics of Atomic Nuclei, Vol. 70, Issue 8; Other Information: DOI: 10.1134/S1063778807080078; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7788
- Country of Publication:
- United States
- Language:
- English
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