New α -Emitting Isotope U 214 and Abnormal Enhancement of α -Particle Clustering in Lightest Uranium Isotopes

• Published in: Physical review letters Vol. 126; no. 15
• Main Authors: Zhang, Z. Y., Yang, H. B., Huang, M. H., Gan, Z. G., Yuan, C. X., Qi, C., Andreyev, A. N., Liu, M. L., Ma, L., Zhang, M. M., Tian, Y. L., Wang, Y. S., Wang, J. G., Yang, C. L., Li, G. S., Qiang, Y. H., Yang, W. Q., Chen, R. F., Zhang, H. B., Lu, Z. W., Xu, X. X., Duan, L. M., Yang, H. R., Huang, W. X., Liu, Z., Zhou, X. H., Zhang, Y. H., Xu, H. S., Wang, N., Zhou, H. B., Wen, X. J., Huang, S., Hua, W., Zhu, L., Wang, X., Mao, Y. C., He, X. T., Wang, S. Y., Xu, W. Z., Li, H. W., Ren, Z. Z., Zhou, S. G.
• Format: Journal Article
• Language: English
• Published: 14-04-2021
• ISSN: 0031-9007; 1079-7114; 1079-7114
• DOI: 10.1103/PhysRevLett.126.152502

A new alpha-emitting isotope U-214, produced by the fusion-evaporation reaction W-182(Ar-36,4n) U-214, was identified by employing the gas-filled recoil separator SHANS and the recoil-a correlation technique. More precise a-decay properties of even-even nuclei U-216,U-218 were also measured in the reactions of Ar-40, Ca-40 beams with W-180,W-182,W- 184 targets. By combining the experimental data, improved alpha-decay reduced widths delta(2) for the even-even Po-Pu nuclei in the vicinity of the magic neutron number N = 126 are deduced. Their systematic trends are discussed in terms of the N-p N-n scheme in order to study the influence of protonneutron interaction on a decay in this region of nuclei. It is strikingly found that the reduced widths of( 214,216)U are significantly enhanced by a factor of two as compared with the NpNn systematics for the 84 <= Z <= 90 and N < 126 even-even nuclei. The abnormal enhancement is interpreted by the strong monopole interaction between the valence protons and neutrons occupying the pi 1f (7/2) and nu 1f(5/2) spin-orbit partner orbits, which is supported by the large-scale shell model calculation.