Search for long lived heaviest nuclei beyond the valley of stability
Abstract
The existence of long lived superheavy nuclei (SHN) is controlled mainly by spontaneous fission and αdecay processes. According to microscopic nuclear theory, spherical shell effects at Z=114, 120, 126 and N=184 provide the extra stability to such SHN to have long enough lifetime to be observed. To investigate whether the socalled “stability island” could really exist around the above Z, N values, the αdecay halflives along with the spontaneous fission and βdecay halflives of such nuclei are studied. The αdecay halflives of SHN with Z=102 120 are calculated in a quantum tunneling model with DDM3Y effective nuclear interaction using Q_{α} values from three different mass formulas prescribed by KouraUnoTachibanaYamada (KUTY), MyersSwiatecki (MS), and MuntianHofmannPatykSobiczewski (MMM). Calculation of spontaneous fission (SF) halflives for the same SHN are carried out using a phenomenological formula and compared with SF halflives predicted by Smolanczuk A possible source of discrepancy between the calculated αdecay halflives of some nuclei and the experimental data of GSI, JINRFLNR, RIKEN, is discussed. In the region of Z=106 108 with N~ 160 164, the βstable SHN _{106}^{268}Sg_{162} is predicted to have highest αdecay halflife (T_{α}~3.2 h) using Q_{α} value from MMM. Interestingly, it is much greater than the recently measured T_{α} (~22 s) of deformed doubly magic _{108}^{270}Hs_{162} nucleus. A few fissionsurvived longlived SHN which are either βstable or having large βdecay halflives are predicted to exist near ^{294}110_{184}, ^{293}110_{183}, ^{296}112_{184}, and ^{298}114_{184}. These nuclei might decay predominantly through αparticle emission.
 Publication:

Physical Review C
 Pub Date:
 April 2008
 DOI:
 10.1103/PhysRevC.77.044603
 arXiv:
 arXiv:0802.3837
 Bibcode:
 2008PhRvC..77d4603C
 Keywords:

 27.90.+b;
 23.60.+e;
 21.10.Hw;
 21.30.Fe;
 220<
 =A;
 Alpha decay;
 Spin parity and isobaric spin;
 Forces in hadronic systems and effective interactions;
 Nuclear Theory;
 Nuclear Experiment;
 Quantum Physics
 EPrint:
 14 pages, 6 figures, 1 table