Shell and pairing gaps from mass measurements: experiment. Magdalena Kowalska CERN, ISOLDE. Masses and nuclear structure. Atomic masses and nuclear binding energy show the net effect of all forces inside the nucleus
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Shell and pairing gaps from mass measurements: experiment
Magdalena Kowalska
CERN, ISOLDE
fp-shell
28
20
sd-shell
8
p-shell
2
s-shell
N
N
N
N
N
Z=28
Z=50
Decrease for smaller N
Z=82
N
N=20
N=50
N=82
N=126
Z
N
N
N=20
N=50
N=28
N=82
Decrease for smaller Z
Z
DS2N/2 [keV]
1/2 x Empirical shell gap
DS2N/2:
1/2 x S2N(Z,N)-S2N(Z,N+2)]
N
Shell gap-zoom2
DS2N/2 [keV]
Decrease for smaller Z
Z
Binding energy
x
Pairing energy
D(3)
Example:
For even N – shell effects visible
D(4)
D3(N) = B(N-1)-2B(N)+B(N+1)
D4(N) = B(N-2)-3B(N-1)+3B(N)-B(N+1)
Smoother than D3, but
Centred at N+1/2 or N-1/2
From S. Naimi et al, Phys. Rev. C 86, 014325 (2012)
Theory: M. Bender, G. F. Bertsch, and P.-H. Heenen, Phys. Rev. C 78, 054312 (2008).
Decrease for smaller Z
Decrease also in spherical mean-filed -> shell gap indeed decreases
Theory: M. Bender, G. F. Bertsch, and P.-H. Heenen,
Phys. Rev. C 78, 054312 (2008).
Decrease for smaller Z
No decrease in spherical mean-filed -> shell gap doesn’t decrease; experimental value changes due to correlations
Theory: M. Bender, G. F. Bertsch, and P.-H. Heenen,
Phys. Rev. C 78, 054312 (2008).
Pairing gap difference: can we call it p-n pairing?
even-Z
even-Z
p-n interaction?
odd-Z
odd-Z
S. Naimi, ISOLTRAP PhD thesis 2010