September 17-20, EMIN - 2009
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On microscopic description of the gamma-ray strength functions S. Kamerdzhiev, D. Voitenkov Institute of Physics and Power Engineering, Obninsk, Russia September 17-20, EMIN - 2009
description
On microscopic description of the gamma-ray strength functions S. Kamerdzhiev , D. Voitenkov Institute of Physics and Power Engineering, Obninsk , Russia. September 17-20, EMIN - 2009. photoabsorption. g -decay. - PowerPoint PPT Presentation
Transcript of September 17-20, EMIN - 2009
On microscopic description of the gamma-ray strength
functions
S. Kamerdzhiev, D. Voitenkov
Institute of Physics and Power Engineering, Obninsk, Russia
September 17-20, EMIN - 2009
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Motivation
g-decay
photoabsorption
1. PSF describes energy distribution of photon emission between “highly-excited” states
Main restrictions:• Energies below 10 MeV• Low spins
PDR
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2. At present there are huge number of experimental data for the transition between excited states and moment values in the excited states.
Our direct aim:
to understand what gives the modern microscopic many-body theory in this field and to compare with the standard QRPA.
The microscopic description is important for neutron-rich nuclei, where phenomenological approaches are questionable
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Extended Theory of Finite Fermi Systems (ETFFS)
1. J. Speth, E. Werner, W. Wild, Phys. Rep. 33 (1977) 127 – 208.
2. S. Kamerdzhiev, J. Speth, G. Tertychny, Phys. Rep. 393 (2004) 1– 86.
[1], [2] are going beyond the standard RPA and QRPA, namely:
Ref. [1] describes transitions between excited states and moment values in excited states.
Ref. [2] accounts for the quasiparticle-phonon coupling and more complex configurations than (Q)RPA ones.
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Magic nuclei
+
The case of moment in the excited state corresponds to S=S’, ω=0.
1 2
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1 2
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S S’ S S’
P. Ring, J. Speth, Nucl. Phys. A235 (1974) 315 – 351
J. Speth, Z. Phys. 239 (1970) 249
V V
V and gs are calculated within the RPA
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New physics:
1. RPA ETFFS
2. Ground state correlations (GSC) in the integral (not in the gs!)
“backward going graphs”
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Non-magic nuclei
Pairing gap Δ≠0
+ +
+ +
+ + +
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Comparison with the QRPA[V. Yu. Ponamarev, Ch. Stoyanov, N. Tsoneva, M. Grinberg, Nucl. Phys. A 635 (1988) 470 – 483.]
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Calculation in 208PbApproximations:
(B-M model)
Our preliminary results:
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Prospects
• 1. Calculations without the above-mentioned approximations
• 2. Coordinate representation• 3. New effects:
where = + +
V.A. Khodel, E.E. Saperstein, Phys. Rep. 1982
M
S S’
M
M
F F F
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Conclusion:
• A new physics is appeared in nuclear spectroscopy and, therefore, in the gamma-ray function business
