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Superdeformed oblate superheavy nuclei - mean field results

Superdeformed oblate superheavy nuclei - mean field results. Introduction – some features of exotic shapes Decay modes & possibility of K-isomers Selfconsistent results 4. Conclusions & possible other exotic SHs. work done with Piotr Jachimowicz and Michał Kowal [PRC 83 (2011) 054302]

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Superdeformed oblate superheavy nuclei - mean field results

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  1. Superdeformed oblate superheavy nuclei - mean field results • Introduction – some features of exotic shapes • Decay modes & possibility of K-isomers • Selfconsistent results 4. Conclusions & possible other exotic SHs work done with Piotr Jachimowicz and Michał Kowal [PRC 83 (2011) 054302] and with Michał Warda.

  2. Ground state shapes

  3. SDO minima

  4. Fission

  5. Formula a’laViola Seaborg from Royer Alpha decay

  6. Alpha decay of Z=120 isotopes

  7. One proton emission half livesapprox. from Nucl. Phys. A 611(1996) 211

  8. Beta decay Since for high-K isomers |M| is reduced,their beta+ decay is even slower.

  9. A fascinating possibility for their longer life-times is related to K-isomerism, high-K configurations at the SDO shape are very likely. OPTIMAL CONFIGURATION: (15/2+)+(9/2-)=>12- (13/2-)+(7/2+)=>10- K=22+

  10. Probable configurations in neighbouring nuclei (A,Z): • 285,119 : 13/2- • 285,120 : 15/2+ • 284,119 : 14- Gallagher rule for the low-lying state: sigma_1 + sigma_2 =0. Check for the chosen configuration: sigma_1 sigma_2 sum Neutrons: 15/2+ 0.44 ; 9/2- -0.44; 0 Protons: 13/2- 0.10 ; 7/2+ -0.16; -0.06.

  11. Effects of the K-isomerism FISSION HINDRANCE: • T_{sf} for odd and odd-odd heavy and superheavy nuclei are by 3-5 orders longer than for their even-even neighbours. • An increase was found for high-K isomers, with respect to (prolate) shape isomers on which they are built, in even 240-244Cm. For SDO superheavy K-isomers two factors combine to increase fission half-life: A) the axial fission path is closed by the conservation of the Kquantum number. B) triaxial barriers increase due to a decrease in pairing caused by the blocking of two neutrons or protons. Additional hindrance of fission is expected for configurations involving blocked high-Omega intruder states.

  12. ALPHA DECAY HINDRANCE: High-K isomer in 270Ds has longer (partial) half-live T_{alpha}= 6.0 ms than the g.s., T_{alpha}(g.s.)=100 microsec. For SDO nuclei, an additional hindrance may result from • a difference between the parent and daughter high-K configuration, • an extra excitation in the daughter, leading to a smaller Q_{alpha}.

  13. YpE

  14. LSD • LSD  1 MeV deeper minima!

  15. NP A 611 Nature

  16. SLy6

  17. Gogny D1

  18. Comparison of self-consistent calculations

  19. Conclusion Selfconsistent results confirm the superdeformed oblate minima in a number of Z>=120, N>=160 nuclei. If a K-isomer with sufficient EM half-life exists & its alpha-decay is delayed, it may live longer than 10^-5 s, i.e. can be experimentally detected. Geometrically, SDO states look like equilibria that are transitional between normal oblate configurations and tight toroids – oblate shapes with a sizable central density depression - for even larger Z (and N). Such toroids may be a next possibility for SHN.

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