Superdeformed oblate superheavy nuclei - mean field results 1.Introduction – some features of exotic shapes 2.Decay modes & possibility of K-isomers 3.Selfconsistent results 4. Conclusions & possible other exotic SHs work done with Piotr Jachimowicz and Michał Kowal [PRC 83 (2011) ] and with Michał Warda.

Ground state shapes

SDO minima

Fission

Alpha decay Formula a’laViola Seaborg from Royer

Alpha decay of Z=120 isotopes

One proton emission half lives approx. from Nucl. Phys. A 611(1996) 211

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

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

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/ ; 9/ ; 0 Protons: 13/ ; 7/ ;

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 Cm. 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 K quantum 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.

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}.

YpE

LSD LSD  1 MeV deeper minima!

NP A 611 Nature

SLy6

Gogny D1

Comparison of self-consistent calculations

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.