Abstract
The recent experiments at FLNR, Dubna, demonstrated that cross-sections to produce SHEs by 48Ca-induced reactions on actinide targets increase beyond Z = 111, reach a maximum of 5 pb at Z = 114 and fall below the 1 pb level at Z = 118. A scenario is proposed to understand the findings within the frame of former experimental results of heavy-element production and theoretical predictions about the stability of the nuclides concerned. New ingredients introduced are: 1) to shift the next proton shell beyond Pb from Z = 114 to Z = 122; 2) the isotopes of the elements Z = 112 to Z = 118 are deformed and their nuclei have oblate shapes; 3) the fission barriers around the next nucleus with doubly closed shells 184306 122 are larger than the neutron separation energies and reach values in the range of 10MeV. The ascent of the flat top at 184306 122 is described by the proposed scenario, which likewise excludes reaching the doubly closed shell region at the top by today’s experimental methods.
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References
Y.T. Oganessian et al., Phys. Rev. Lett. 83, 3154 (1999).3154
Y.T. Oganessian et al., J. Phys. G Nucl. Part. Phys. 34, R.165 (2007).
R. Eichler et al., Nature 83, 487 (2007).
S. Hofmann et al., Eur. Phys. J. A 32, 251 (2007).
Y.T. Oganessian, TAN07, Davos, unpublished (2007).
P. Armbruster, Annu. Rev. Nucl. Part. Sci. 35, 135 (1985).
P. Armbruster, Annu. Rev. Nucl. Part. Sci. 50, 411 (2000).
H. Meldner, Ark. Fys. 36, 593 (1967).
A. Sobiczewski, F. Gareev, B.N. Kalinkin, Phys. Lett. 22, 500 (1966).
M. Göppert-Mayer, H.D. Jensen, Elementary Theory of Nuclear Shell Structure (Wiley, New York, NY, 1955).
J.F. Berger et al., Nucl. Phys. A 685, 1c (2001).
M. Bender et al., Phys. Lett. B 515, 42 (2001).
G. Audi et al., Nucl. Phys. A 729 (2003).
F. Jachello, Phys. Rev. Lett. 87, 052502 (2001).
R. Casten, Eur. Phys. J. A 20, 167 (2004).
M. Bernas et al., Phys. Lett. B 415, 111 (1997).
J. Jolie et al., Phys. Rev. Lett. 87, 162501 (2000).
J. Dvorak et al., Phys. Rev. Lett. 97, 242502 (2006).
P. Reiter et al., Phys. Rev. Lett. 82, 809 (1999).
M. Leino et al., Eur. Phys. J. A 6, 63 (1999).
P. Möller et al., At. Data Nucl. Data Tables 59, 185 (1995).
A. Sobiczewski, Z. Patyk, S. Cwiok, Phys. Lett. B 186, 6 (1987).
P. Ring, Prog. Part. Nucl. Phys. 37, 193 (1996).
C. Schmitt et al., Phys. Rev Lett. 99, 042701 (2007).
K.H. Schmidt et al., Nucl. Phys. A 665, 221 (2000).
K.H. Schmidt, W. Morawek, Rep. Progr. Phys. 54, 949 (1991).
A.R. Junghans et al., Nucl. Phys. A 629, 635 (1998).
A. Heinz et al., Nucl. Phys. A 713, 3 (2003).
J.R. Nix, Annu. Rev. Nucl. Part. Sci. 22, 65 (1972).
M. Bender, P.H. Heenen, P.G. Reinhard, Rev. Mod. Phys. 75, 121 (2003).
R. Smolanczuk, Phys. Rev. C 56, 812 (1997).
Y.T. Oganessian, A.S. Iljinov, A.G. Demin, S.P. Tretyakova, Nucl. Phys. A 239, 353 (1975).
K. Morita et al., J. Phys. Soc. Jpn. 73, 2593 (2004).
T. Sikkeland, Ark. Fys. 36, 539 (1967).
P. Armbruster et al., GSI-Jahresberichte 1976/77, GSIDarmstadt, J1-1977/78.
K.E. Gregorich et al., LBNL-Report 63617 (2007).
W. Swiatecki, K. Siwek-Wilczynska, J. Wilczynski, Phys. Rev. C 71, 014602 (2005).
Y. Aritomo, M. Ohta, Nucl. Phys. A 764, 149 (2006).
Y.T. Oganessian et al., Phys. Rev. C 70, 064609 (2004).
A.V. Ignatyuk et al., Sov. J. Nucl. Phys. 21, 612 (1975).
Y.A. Lazarev et al., Phys. Rev. Lett. 75, 1903 (1995).
S. Hofmann, private communication (2007).
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Armbruster, P. Shifting the closed proton shell to Z = 122 —A possible scenario to understand the production of superheavy elements Z = 112−118. Eur. Phys. J. A 37, 159–167 (2008). https://doi.org/10.1140/epja/i2008-10607-5
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DOI: https://doi.org/10.1140/epja/i2008-10607-5