Nature of 0+ states in Deformed Nuclei
18
Gd
Dy
Sm
Er
Yb
Hf
14
12
Measured lifetimes of
C. Casarella, S.R. Lesher, A. Aprahamian et al.
162
162Dy
Dy
156Gd
16
N0+
The nature of
states in deformed nuclei
remains a grand challenge for nuclear
structure physics. Recently, a large number of
0+ states have been observed in deformed
nuclei but their characterization remains
elusive. We have measured the lifetimes of 58
levels in 162Dy using Doppler Shift Attenuation
following ( n, n’g) at the Univ. of Kentucky.
Number of observed 0+ states
0+
178Hf
10
8
6
4
2
0
144
0+
148
152
states
156
160
164
A
168
172
176
180
184
0+ Lifetimes using 160Gd(n,n'γ)
The exact nature of 0+ states, a fundamental excitation in deformed nuclei,
has remained an enigma for several decades. Full elucidation of this nature
hinges on the measurement of nuclear lifetimes. We measured several
crucial lifetimes of 0+ states in 160Gd with the Doppler Shift Attenuation
Method, and have identified a two-phonon gg vibration in the third 0+ band.
Eg (keV)
1149.3
1149.2
Eg = 1149.12(5) keV
1149.1
En = 1.5 MeV
t = 21 ± 1 fs
1149
1148.9
F(t) = 0.665 ± 0.010
1148.8
1148.7
1148.6
-1
-0.5
0
cos(q)
0.5
1
S. R. Lesher, C. Casarella, A. Aprahamian, et.
al, Phys. Rev. C 91, 054317 (2015)