New
-emitting isotope
U and abnormal enhancement of
-particle clustering in lightest uranium isotopes
Zhang, Z. Y.*; Yang, H. B.*; Andreyev, A. N.; Liu, M. L.*; Ma, L.*; 他37名*
Zhang, Z. Y.*; Yang, H. B.*; Andreyev, A. N.; Liu, M. L.*; Ma, L.*; 37 of others*
A new
-emitting isotope
U, produced by the fusion-evaporation reaction
W(
Ar,4n)
U, was identified by employing the gas-filled recoil separator SHANS and the recoil-
correlation technique. More precise
-decay properties of even-even nuclei
U were also measured in the reactions of
Ar,
Ca beams with
W targets. By combining the experimental data, improved
-decay reduced widths 
for the even-even Po-Pu nuclei in the vicinity of the magic neutron number
= 126 are deduced. Their systematic trends are discussed in terms of the
scheme in order to study the influence of proton-neutron interaction on
decay in this region of nuclei. It is strikingly found that the reduced widths of
U are significantly enhanced by a factor of two as compared with the
systematics for the 84
90 and
126 even-even nuclei. The abnormal enhancement is interpreted by the strong monopole interaction between the valence protons and neutrons occupying the
1
and
1
spin-orbit partner orbits, which is supported by the large-scale shell model calculation.