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Cook KJ, Rafferty DC, Hinde DJ, Simpson EC, Dasgupta M, Corradi L, Evers M, Fioretto E, Jeung D, Lobanov N, Luong DH, Mijatović T, Montagnoli G, Stefanini AM, Szilner S. Colliding heavy nuclei take multiple identities on the path to fusion. Nat Commun 2023; 14:7988. [PMID: 38042951 PMCID: PMC10693600 DOI: 10.1038/s41467-023-43817-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 11/21/2023] [Indexed: 12/04/2023] Open
Abstract
The properties of superheavy elements probe extremes of physics and chemistry. They are synthesised at accelerator laboratories using nuclear fusion, where two atomic nuclei collide, stick together (capture), then with low probability evolve to a compact superheavy nucleus. The fundamental microscopic mechanisms controlling fusion are not fully understood, limiting predictive capability. Even capture, considered to be the simplest stage of fusion, is not matched by models. Here we show that collisions of 40Ca with 208Pb, experience an 'explosion' of mass and charge transfers between the nuclei before capture, with unexpectedly high probability and complexity. Ninety different partitions of the protons and neutrons between the projectile-like and target-like nuclei are observed. Since each is expected to have a different probability of fusion, the early stages of collisions may be crucial in superheavy element synthesis. Our interpretation challenges the current view of fusion, explains both the successes and failures of current capture models, and provides a framework for improved models.
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Affiliation(s)
- Kaitlin J Cook
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia.
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, 48824, MI, USA.
| | - Dominic C Rafferty
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia
| | - David J Hinde
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia
| | - Edward C Simpson
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia
| | - Mahananda Dasgupta
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia
| | - Lorenzo Corradi
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy
| | - Maurits Evers
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia
| | - Enrico Fioretto
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy
| | - Dongyun Jeung
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia
| | - Nikolai Lobanov
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia
| | - Duc Huy Luong
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, The Australian National University, Canberra, 2601, ACT, Australia
| | | | - Giovanna Montagnoli
- Dipartimento di Fisica e Astronomia, Universita di Padova, via Marzolo 8, Padova, I-35131, Italy
| | - Alberto M Stefanini
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, I-35020, Italy
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Stefanini AM, Montagnoli G, Del Fabbro M, Colucci G, Čolović P, Corradi L, Fioretto E, Galtarossa F, Goasduff A, Grebosz J, Heine M, Jaworski G, Mazzocco M, Mijatović T, Szilner S, Bajzek M, Brugnara D, Siciliano M, Zanon I. Fusion Hindrance and Pauli Blocking in 58 Ni + 64 Ni. EPJ WEB OF CONFERENCES 2019. [DOI: 10.1051/epjconf/201922301062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
58Ni +64Ni is the first case where the influence of positive Q-value transfer channels on sub-barrier fusion was evidenced, in a very well known experiment by Beckerman et al., by comparing with the two systems 58Ni + 58Ni and 64Ni+64Ni. Subsequent measurements on 64Ni + 64Ni showed that fusion hindrance is clearly present in this case. On the other hand, no indication of hindrance can be observed for 58Ni + 64Ni down to the measured level of 0.1 mb. In the present experiment the excitation function has been extended by two orders of magnitude downward. The cross sections for 58Ni + 64Ni continue decreasing very smoothly below the barrier, down to '1 µb. The logarithmic slope of the excitation function increases slowly, showing a tendency to saturate at the lowest energies. No maximum of the astrophysical S -factor is observed. Coupled-channels (CC) calculations using a Woods-Saxon potential and includinginelastic excitations only, underestimate the sub-barrier cross sections by a large amount. Good agreement is found by adding two-neutron transfer couplings to a schematical level. This behaviour is quite different from what already observed for 64Ni+ 64Ni (no positive Q-value transfer channels available), where a clear low-energy maximum of the S -factorappears, and whose excitation function is overestimated by a standard Woods-Saxon CC calculation. No hindrance effect is observed in 58Ni+ 64Ni in the measured energy range. This trend at deep sub-barrier energies reinforces the recent suggestion that the availability of several states following transfer with Q>0, effectively counterbalances the Pauli repulsion that, in general, is predicted to reduce tunneling probability inside the Coulomb barrier.
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Galtarossa F, Stefanini AM, Montagnoli G, Jiang CL, Colucci G, Bottoni S, Broggini C, Caciolli A, Colović P, Corradi L, Courtin S, Depalo R, Fioretto E, Fruet G, Gal A, Goasduff A, Heine M, Hu SP, Kaur M, Mijatović T, Montanari D, Scarlassara F, Strano E, Szilner S, Zhang GX. Fusion hindrance for the positive Q-value system 12C+ 30Si. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Bezzina LT, Simpson EC, Carter IP, Dasgupta M, Ebadi T, Hinde DJ, Rafferty DC. Determination of Precision Fusion Cross Sections Using a High Efficiency Superconducting Solenoidal Separator. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Simenel C, Godbey K, Umar A, Vo-Phuoc K, Dasgupta M, Hinde DJ, Simpson EC. Effect of Pauli repulsion and transfer on fusion. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ichikawa T. Universal damping mechanism of quantum vibrations in deep sub-barrier fusion reactions. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Courtin S, Jiang C, Fruet G, Auranen K, Avila M, Ayangeakaa A, Back B, Bottoni S, Carpenter M, Dickerson C, DiGiovine B, Greene J, Henderson D, Hoffman C, Janssens R, Kay B, Kuvin S, Lauritsen T, Pardo R, Rehm K, Santiago-Gonzalez D, Sethi J, Seweryniak D, Talwar R, Ugalde C, Zhu S, Deibel C, Marley S, Bourgin D, Haas F, Heine M, Montanari D, Jenkins D, Morris L, Lefebvre-Schuhl A, Almaraz-Calderon S, Fang X, Tang X, Alcorta M, Bucher B, Albers M, Bertone P. How well do we understand the reaction rate of C burning? EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Hagino K. Evolving theoretical descriptions of heavy-ion fusion: from phenomenological to microscopic approaches. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Montagnoli G. From fusion hindrance to oscillations. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158600027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Stefanini AM, Montagnoli G, Corradi L, Courtin S, Bourgin D, Fioretto E, Goasduff A, Grebosz J, Haas F, Mazzocco M, Mijatović T, Montanari D, Parascandolo C, Scarlassara F, Strano E, Szilner S, Toniolo N, Torresi D. Fusion Hindrance and Quadrupole Collectivity in Collisions of A≃50 Nuclei: The Case of 48Ti + 58Fe. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158600057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Jiang CL, Stefanini AM, Esbensen H, Rehm KE, Almaraz-Calderon S, Back BB, Corradi L, Fioretto E, Montagnoli G, Scarlassara F, Montanari D, Courtin S, Bourgin D, Haas F, Goasduff A, Szilner S, Mijatovic T. Fusion hindrance for a positive-q-value system (24)Mg+(30)Si. PHYSICAL REVIEW LETTERS 2014; 113:022701. [PMID: 25062170 DOI: 10.1103/physrevlett.113.022701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Indexed: 06/03/2023]
Abstract
Measurements of the excitation function for the fusion of (24)Mg+(30)Si (Q=17.89 MeV)have been extended toward lower energies with respect to previous experimental data. The S-factor maximum observed in this large, positive-Q-value system is the most pronounced among such systems studied thus far. The significance and the systematics of an S-factor maximum in systems with positive fusion Q values are discussed. This result would strongly impact the extrapolated cross sections and reaction rates in the carbon and oxygen burnings and, thus, the study of the history of stellar evolution.
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Affiliation(s)
- C L Jiang
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A M Stefanini
- INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Padova), Italy
| | - H Esbensen
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K E Rehm
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S Almaraz-Calderon
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B B Back
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - L Corradi
- INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Padova), Italy
| | - E Fioretto
- INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Padova), Italy
| | - G Montagnoli
- Dipartimento di Fisica e Astronomia, Universitá di Padova, and INFN, Sezione di Padova, IT-35131 Padova, Italy
| | - F Scarlassara
- Dipartimento di Fisica e Astronomia, Universitá di Padova, and INFN, Sezione di Padova, IT-35131 Padova, Italy
| | - D Montanari
- Dipartimento di Fisica e Astronomia, Universitá di Padova, and INFN, Sezione di Padova, IT-35131 Padova, Italy
| | - S Courtin
- IPHC and University of Strasbourg, CNRS/IN2P3,67037 Strasbourg Cedex2, France
| | - D Bourgin
- IPHC and University of Strasbourg, CNRS/IN2P3,67037 Strasbourg Cedex2, France
| | - F Haas
- IPHC and University of Strasbourg, CNRS/IN2P3,67037 Strasbourg Cedex2, France
| | - A Goasduff
- CSNSM, CNRS/IN2P3 and University Paris-Sud, F-91405 Orsay Campus, France
| | - S Szilner
- Ruder Boskovic Institute, HR-10002 Zagreb, Croatia
| | - T Mijatovic
- Ruder Boskovic Institute, HR-10002 Zagreb, Croatia
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Stefanini A, Montagnoli G, Corradi L, Courtin S, Fioretto E, Grebosz J, Haas F, Jia H, Mazzocco M, Michelagnoli C, Mijatović T, Montanari D, Parascandolo C, Scarlassara F, Strano E, Szilner S, Torresi D, Ur C. Fusion of28Si +28Si: oscillations above the barrier and the behavior down to 1μb. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146603082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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13
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Dasgupta M, Luong D, Hinde D, Evers M. Many-body Quantum Reaction Dynamics near the Fusion Barrier. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146601003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Jiang CL, Back BB, Esbensen H, Janssens RVF, Rehm KE, Charity RJ. Origin and consequences of 12C+12C fusion resonances at deep sub-barrier energies. PHYSICAL REVIEW LETTERS 2013; 110:072701. [PMID: 25166370 DOI: 10.1103/physrevlett.110.072701] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Indexed: 06/03/2023]
Abstract
Previous explanations for the resonance behavior of (12)C+(12)C fusion at low energies were based on a nonresonant compound-nucleus background and an additional contribution from a series of resonances. This separation into "resonance" and "background" contributions of the cross section is artificial. We propose to explain this phenomenon through the impact on the cross section of the relatively large spacings and the narrow widths of (24)Mg compound levels in the corresponding excitation-energy region.
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Affiliation(s)
- C L Jiang
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B B Back
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - H Esbensen
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R V F Janssens
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K E Rehm
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R J Charity
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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Shrivastava A, Navin A, Lemasson A, Ramachandran K, Nanal V, Rejmund M, Hagino K, Ichikawa T, Bhattacharyya S, Chatterjee A, Kailas S, Mahata K, Parkar VV, Pillay RG, Rout PC. Exploring fusion at extreme sub-barrier energies with weakly bound nuclei. PHYSICAL REVIEW LETTERS 2009; 103:232702. [PMID: 20366145 DOI: 10.1103/physrevlett.103.232702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Indexed: 05/29/2023]
Abstract
Results of measurement of residues formed in fusion of (6)Li with (198)Pt in the energy range of 0.68 < E/V(b) < 1.3 using a new sensitive off-beam technique are reported. The fusion excitation function and the derived average angular momenta do not indicate a change of slope at deep sub-barrier energies, contrary to recent observations. The present results for a system with weakly bound projectile confront the current understanding of the fusion hindrance at these low energies, underlying the role of internal reorganization on the dynamical path towards fusion.
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Affiliation(s)
- A Shrivastava
- Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
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Ichikawa T, Hagino K, Iwamoto A. Signature of smooth transition from sudden to adiabatic states in heavy-ion fusion reactions at deep sub-barrier energies. PHYSICAL REVIEW LETTERS 2009; 103:202701. [PMID: 20365981 DOI: 10.1103/physrevlett.103.202701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Indexed: 05/29/2023]
Abstract
We propose a novel extension of the standard coupled-channels framework for heavy-ion reactions in order to analyze fusion reactions at deep-sub-barrier incident energies. This extension simulates a smooth transition between the two-body and the adiabatic one-body states. To this end, we damp gradually the off-diagonal part of the coupling potential, for which the position of the onset of the damping varies for each eigenchannel. We show that this model accounts well for the steep falloff of the fusion cross sections for the (16)O + (208)Pb, (64)Ni + (64)Ni, and (58)Ni + (58)Ni reactions.
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Affiliation(s)
- Takatoshi Ichikawa
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
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Dasgupta M, Hinde DJ, Diaz-Torres A, Bouriquet B, Low CI, Milburn GJ, Newton JO. Beyond the coherent coupled channels description of nuclear fusion. PHYSICAL REVIEW LETTERS 2007; 99:192701. [PMID: 18233072 DOI: 10.1103/physrevlett.99.192701] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Indexed: 05/25/2023]
Abstract
New measurements of fusion cross sections at deep sub-barrier energies for the reactions 16O+{204,208}Pb show a steep but almost saturated logarithmic slope, unlike 64Ni-induced reactions. Coupled channels calculations cannot simultaneously reproduce these new data and above-barrier cross-sections with the same Woods-Saxon nuclear potential. It is argued that this highlights an inadequacy of the coherent coupled channels approach. It is proposed that a new approach explicitly including gradual decoherence is needed to allow a consistent description of nuclear fusion.
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Affiliation(s)
- M Dasgupta
- Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT, Australia
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