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Banerjee K, Hinde DJ, Dasgupta M, Simpson EC, Jeung DY, Simenel C, Swinton-Bland BMA, Williams E, Carter IP, Cook KJ, David HM, Düllmann CE, Khuyagbaatar J, Kindler B, Lommel B, Prasad E, Sengupta C, Smith JF, Vo-Phuoc K, Walshe J, Yakushev A. Mechanisms Suppressing Superheavy Element Yields in Cold Fusion Reactions. PHYSICAL REVIEW LETTERS 2019; 122:232503. [PMID: 31298876 DOI: 10.1103/physrevlett.122.232503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/17/2018] [Indexed: 06/10/2023]
Abstract
Superheavy elements are formed in fusion reactions which are hindered by fast nonequilibrium processes. To quantify these, mass-angle distributions and cross sections have been measured, at beam energies from below-barrier to 25% above, for the reactions of ^{48}Ca, ^{50}Ti, and ^{54}Cr with ^{208}Pb. Moving from ^{48}Ca to ^{54}Cr leads to a drastic fall in the symmetric fission yield, which is reflected in the measured mass-angle distribution by the presence of competing fast nonequilibrium deep inelastic and quasifission processes. These are responsible for reduction of the compound nucleus formation probablity P_{CN} (as measured by the symmetric-peaked fission cross section), by a factor of 2.5 for ^{50}Ti and 15 for ^{54}Cr in comparison to ^{48}Ca. The energy dependence of P_{CN} indicates that cold fusion reactions (involving ^{208}Pb) are not driven by a diffusion process.
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Affiliation(s)
- K Banerjee
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - D J Hinde
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - M Dasgupta
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - E C Simpson
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - D Y Jeung
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - C Simenel
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - B M A Swinton-Bland
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - E Williams
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - I P Carter
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - K J Cook
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - H M David
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - Ch E Düllmann
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
- Helmholtz Institute Mainz, 55099 Mainz, Germany
- Institut für Kernchemie, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - J Khuyagbaatar
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
- Helmholtz Institute Mainz, 55099 Mainz, Germany
| | - B Kindler
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - B Lommel
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - E Prasad
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - C Sengupta
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - J F Smith
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - K Vo-Phuoc
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - J Walshe
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra ACT 2601, Australia
| | - A Yakushev
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
- Helmholtz Institute Mainz, 55099 Mainz, Germany
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