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Bishop J, Parker CE, Rogachev GV, Ahn S, Koshchiy E, Brandenburg K, Brune CR, Charity RJ, Derkin J, Dronchi N, Hamad G, Jones-Alberty Y, Kokalova T, Massey TN, Meisel Z, Ohstrom EV, Paneru SN, Pollacco EC, Saxena M, Singh N, Smith R, Sobotka LG, Soltesz D, Subedi SK, Voinov AV, Warren J, Wheldon C. Neutron-upscattering enhancement of the triple-alpha process. Nat Commun 2022; 13:2151. [PMID: 35444209 PMCID: PMC9021293 DOI: 10.1038/s41467-022-29848-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 03/31/2022] [Indexed: 11/30/2022] Open
Abstract
The neutron inelastic scattering of carbon-12, populating the Hoyle state, is a reaction of interest for the triple-alpha process. The inverse process (neutron upscattering) can enhance the Hoyle state’s decay rate to the bound states of 12C, effectively increasing the overall triple-alpha reaction rate. The cross section of this reaction is impossible to measure experimentally but has been determined here at astrophysically-relevant energies using detailed balance. Using a highly-collimated monoenergetic beam, here we measure neutrons incident on the Texas Active Target Time Projection Chamber (TexAT TPC) filled with CO2 gas, we measure the 3α-particles (arising from the decay of the Hoyle state following inelastic scattering) and a cross section is extracted. Here we show the neutron-upscattering enhancement is observed to be much smaller than previously expected. The importance of the neutron-upscattering enhancement may therefore not be significant aside from in very particular astrophysical sites (e.g. neutron star mergers). The triple-alpha process plays a role in nucleosynthesis, in the formation of 12C. Here, the authors discuss the rate and role of the neutron upscattering phenomenon on the triple-alpha process in a multi-step process.
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Affiliation(s)
- J Bishop
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA.
| | - C E Parker
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA
| | - G V Rogachev
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA.,Department of Physics & Astronomy, Texas A&M University, College Station, TX, 77843, USA.,Nuclear Solutions Institute, Texas A&M University, College Station, TX, 77843, USA
| | - S Ahn
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA.,Center for Exotic Nuclear Studies, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea
| | - E Koshchiy
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA
| | - K Brandenburg
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - C R Brune
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - R J Charity
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA
| | - J Derkin
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - N Dronchi
- Department of Physics, Washington University, St. Louis, MO, 63130, USA
| | - G Hamad
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - Y Jones-Alberty
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - Tz Kokalova
- School of Physics and Astronomy, University of Birmingham, Birmingham, UK
| | - T N Massey
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - Z Meisel
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - E V Ohstrom
- Department of Physics, Washington University, St. Louis, MO, 63130, USA
| | - S N Paneru
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - E C Pollacco
- IRFU, CEA, Université Paris-Saclay, Gif-Sur-Yvette, France
| | - M Saxena
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - N Singh
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - R Smith
- Department of Engineering and Mathematics, Sheffield Hallam University, Sheffield, S1 1WB, UK
| | - L G Sobotka
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA.,Department of Physics, Washington University, St. Louis, MO, 63130, USA.,McDonnell Center for the Space Sciences, Washington University, St. Louis, MO, 63130, USA
| | - D Soltesz
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - S K Subedi
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - A V Voinov
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - J Warren
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - C Wheldon
- School of Physics and Astronomy, University of Birmingham, Birmingham, UK
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Smith R, Kokalova T, Wheldon C, Bishop JE, Freer M, Curtis N, Parker DJ. New Measurement of the Direct 3α Decay from the ^{12}C Hoyle State. Phys Rev Lett 2017; 119:132502. [PMID: 29341725 DOI: 10.1103/physrevlett.119.132502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Indexed: 06/07/2023]
Abstract
Excited states in certain atomic nuclei possess an unusual structure, where the dominant degrees of freedom are those of α clusters rather than individual nucleons. It has been proposed that the diffuse 3α system of the ^{12}C Hoyle state may behave like a Bose-Einstein condensate, where the α clusters maintain their bosonic identities. By measuring the decay of the Hoyle state into three α particles, we obtained an upper limit for the rare direct 3α decay branch of 0.047%. This value is now at a level comparable with theoretical predictions and could be a sensitive probe of the structure of this state.
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Affiliation(s)
- R Smith
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Tz Kokalova
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - C Wheldon
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - J E Bishop
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - M Freer
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - N Curtis
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - D J Parker
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
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Marín-Lámbarri DJ, Bijker R, Freer M, Gai M, Kokalova T, Parker DJ, Wheldon C. Evidence for triangular D3h symmetry in 12C. Phys Rev Lett 2014; 113:012502. [PMID: 25032922 DOI: 10.1103/physrevlett.113.012502] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Indexed: 05/28/2023]
Abstract
We report a measurement of a new high spin Jπ=5- state at 22.4(2) MeV in 12C which fits very well to the predicted (ground state) rotational band of an oblate equilateral triangular spinning top with a D3h symmetry characterized by the sequence 0+, 2+, 3-, 4±, 5- with almost degenerate 4+ and 4- (parity doublet) states. Such a D3h symmetry was observed in triatomic molecules, and it is observed here for the first time in nuclear physics. We discuss a classification of other rotation-vibration bands in 12C such as the (0+) Hoyle band and the (1-) bending mode band and suggest measurements in search of the predicted ("missing") states that may shed new light on clustering in 12C and light nuclei. In particular, the observation (or nonobservation) of the predicted ("missing") states in the Hoyle band will allow us to conclude the geometrical arrangement of the three alpha particles composing the Hoyle state at 7.654 MeV in 12C.
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Affiliation(s)
- D J Marín-Lámbarri
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - R Bijker
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A.P. 70-543, 04510 México, D.F., Mexico
| | - M Freer
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - M Gai
- LNS at Avery Point, University of Connecticut, Groton, Connecticut 06340-6097, USA and Wright Lab, Department of Physics, Yale University, New Haven, Connecticut 06520-8124, USA
| | - Tz Kokalova
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - D J Parker
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - C Wheldon
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
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