Neutronium: Difference between revisions

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===Scattering resonances with multiple neutrons===
===Scattering resonances with multiple neutrons===


The dineutron, containing two neutrons, is not a stable bound particle, but an extremely short-lived resonance state produced by nuclear reactions in the decay of beryllium-16. Evidence reported in 2012 for the resonance<ref>{{cite journal | author = Schirber, M. | title = Nuclei Emit Paired-up Neutrons | journal = [[Physics (American Physical Society magazine)|Physics]] | date = 2012 | volume = 5 | page = 30 | doi = 10.1103/Physics.5.30 | bibcode = 2012PhyOJ...5...30S }}</ref><ref>{{cite journal | author = Spyrou, A. | display-authors = 4 | author2 = Kohley, Z. | author3 = Baumann, T. | author4 = Bazin, D. | author5 = Brown, B. A. | author6 = Christian, G. | author7 = DeYoung, P. A. | author8 = Finck, J. E. | author9 = Frank, N. | author10 = Lunderberg, E. | author11 = Mosby, S. | author12 = Peters, W. A. | author13 = Schiller, A. | author14 = Smith, J. K. | author15 = Snyder, J. | author16 = Strongman, M. J. | author17 = Thoennessen, M. | author18 = Volya, A. | title = First Observation of Ground State Dineutron Decay: <sup>16</sup>Be | journal = [[Physical Review Letters]] | date = 2012 | volume = 108 | issue = 10 | page = 102501 | doi = 10.1103/PhysRevLett.108.102501 | pmid = 22463404 | bibcode = 2012PhRvL.108j2501S | doi-access = free | url = https://www.osti.gov/biblio/1104191 }}</ref> was disputed,<ref>Marqués, F. M., Orr, N. A., Achouri, N. L., Delaunay, F., & Gibelin, J. (2012). Comment on “First Observation of Ground State Dineutron Decay: Be 16”. Physical Review Letters, 109(23), 239201.</ref> but new work reportedly clears up the issues.<ref>{{Cite journal |last1=Monteagudo |first1=B. |last2=Marqués |first2=F. M. |last3=Gibelin |first3=J. |last4=Orr |first4=N. A. |last5=Corsi |first5=A. |last6=Kubota |first6=Y. |last7=Casal |first7=J. |last8=Gómez-Camacho |first8=J. |last9=Authelet |first9=G. |last10=Baba |first10=H. |last11=Caesar |first11=C. |last12=Calvet |first12=D. |last13=Delbart |first13=A. |last14=Dozono |first14=M. |last15=Feng |first15=J. |date=2024-02-23 |title=Mass, Spectroscopy, and Two-Neutron Decay of $^{16}\mathrm{Be}$ |url=https://eprints.whiterose.ac.uk/211204/1/2401.16817.pdf |journal=Physical Review Letters |volume=132 |issue=8 |pages=082501 |doi=10.1103/PhysRevLett.132.082501}}</ref>
The dineutron, containing two neutrons, is not a stable bound particle, but an extremely short-lived resonance state produced by nuclear reactions in the decay of beryllium-16. Evidence reported in 2012 for the resonance<ref>{{cite journal | author = Schirber, M. | title = Nuclei Emit Paired-up Neutrons | journal = [[Physics (American Physical Society magazine)|Physics]] | date = 2012 | volume = 5 | article-number = 30 | doi = 10.1103/Physics.5.30 | bibcode = 2012PhyOJ...5...30S }}</ref><ref>{{cite journal | author = Spyrou, A. | display-authors = 4 | author2 = Kohley, Z. | author3 = Baumann, T. | author4 = Bazin, D. | author5 = Brown, B. A. | author6 = Christian, G. | author7 = DeYoung, P. A. | author8 = Finck, J. E. | author9 = Frank, N. | author10 = Lunderberg, E. | author11 = Mosby, S. | author12 = Peters, W. A. | author13 = Schiller, A. | author14 = Smith, J. K. | author15 = Snyder, J. | author16 = Strongman, M. J. | author17 = Thoennessen, M. | author18 = Volya, A. | title = First Observation of Ground State Dineutron Decay: <sup>16</sup>Be | journal = [[Physical Review Letters]] | date = 2012 | volume = 108 | issue = 10 | article-number = 102501 | doi = 10.1103/PhysRevLett.108.102501 | pmid = 22463404 | bibcode = 2012PhRvL.108j2501S | osti = 1104191 | doi-access = free }}</ref> was disputed,<ref>Marqués, F. M., Orr, N. A., Achouri, N. L., Delaunay, F., & Gibelin, J. (2012). Comment on "First Observation of Ground State Dineutron Decay: Be 16". Physical Review Letters, 109(23), 239201.</ref> but new work reportedly clears up the issues.<ref>{{Cite journal |last1=Monteagudo |first1=B. |last2=Marqués |first2=F. M. |last3=Gibelin |first3=J. |last4=Orr |first4=N. A. |last5=Corsi |first5=A. |last6=Kubota |first6=Y. |last7=Casal |first7=J. |last8=Gómez-Camacho |first8=J. |last9=Authelet |first9=G. |last10=Baba |first10=H. |last11=Caesar |first11=C. |last12=Calvet |first12=D. |last13=Delbart |first13=A. |last14=Dozono |first14=M. |last15=Feng |first15=J. |date=2024-02-23 |title=Mass, Spectroscopy, and Two-Neutron Decay of $^{16}\mathrm{Be}$ |url=https://eprints.whiterose.ac.uk/211204/1/2401.16817.pdf |journal=Physical Review Letters |volume=132 |issue=8 |article-number=082501 |doi=10.1103/PhysRevLett.132.082501 |pmid=38457706 |osti=2473832 }}</ref>


The dineutron hypothesis had been used in theoretical studies of the structure of [[exotic nuclei]]. For example <sup>11</sup>Li is modeled as a dineutron bound to a <sup>9</sup>Li core.<ref name="Bertulani 1993 281–376">{{cite journal | last1 = Bertulani | first1 = C. A. | last2 = Canto | first2 = L. F. | last3 = Hussein | first3 = M. S. | title = The Structure And Reactions Of Neutron-Rich Nuclei | journal = [[Physics Reports]] | date = 1993 | volume = 226 | issue = 6 | pages = 281–376 | bibcode = 1993PhR...226..281B | doi = 10.1016/0370-1573(93)90128-Z | url = http://www.tamu-commerce.edu/physics/carlos/papers/PRep226_1993_281.pdf | archive-url = https://web.archive.org/web/20110928120249/http://www.tamu-commerce.edu/physics/carlos/papers/PRep226_1993_281.pdf | url-status = dead | archive-date = 2011-09-28 }}</ref><ref>{{cite journal | last1 = Hagino | first1 = K. | last2 = Sagawa | first2 = H. | last3 = Nakamura | first3 = T. | last4 = Shimoura | first4 = S. | title = Two-particle correlations in continuum dipole transitions in Borromean nuclei | journal = [[Physical Review C]] | date = 2009 | volume = 80 | issue = 3 | page = 1301 | arxiv = 0904.4775 | bibcode = 2009PhRvC..80c1301H | doi = 10.1103/PhysRevC.80.031301 | s2cid = 119293335 }}</ref> A system made up of only two neutrons is not bound, though the attraction between them is very nearly enough to make them so.<ref>{{cite journal | last1 = MacDonald | first1 = J. | last2 = Mullan | first2 = D. J. | date = 2009 | title = Big Bang Nucleosynthesis: The Strong Nuclear Force meets the Weak Anthropic Principle | journal = [[Physical Review D]] | volume = 80 | issue = 4 | page = 3507 | arxiv = 0904.1807 | bibcode = 2009PhRvD..80d3507M | doi = 10.1103/PhysRevD.80.043507 | s2cid = 119203730 }}</ref> This has some consequences on [[nucleosynthesis]] and the [[abundance of the chemical elements]].<ref name="Bertulani 1993 281–376"/><ref>{{cite journal | last1 = Kneller | first1 = J. P. | last2 = McLaughlin | first2 = G. C. | author2-link = Gail McLaughlin | title = The Effect of Bound Dineutrons upon BBN | journal = [[Physical Review D]] | date = 2004 | volume = 70 | issue = 4 | page = 3512 | arxiv = astro-ph/0312388 | bibcode = 2004PhRvD..70d3512K | doi = 10.1103/PhysRevD.70.043512 | s2cid = 119060865 }}</ref>
The dineutron hypothesis had been used in theoretical studies of the structure of [[exotic nuclei]]. For example <sup>11</sup>Li is modeled as a dineutron bound to a <sup>9</sup>Li core.<ref name="Bertulani 1993 281–376">{{cite journal | last1 = Bertulani | first1 = C. A. | last2 = Canto | first2 = L. F. | last3 = Hussein | first3 = M. S. | title = The Structure And Reactions Of Neutron-Rich Nuclei | journal = [[Physics Reports]] | date = 1993 | volume = 226 | issue = 6 | pages = 281–376 | bibcode = 1993PhR...226..281B | doi = 10.1016/0370-1573(93)90128-Z | url = http://www.tamu-commerce.edu/physics/carlos/papers/PRep226_1993_281.pdf | archive-url = https://web.archive.org/web/20110928120249/http://www.tamu-commerce.edu/physics/carlos/papers/PRep226_1993_281.pdf | archive-date = 2011-09-28 }}</ref><ref>{{cite journal | last1 = Hagino | first1 = K. | last2 = Sagawa | first2 = H. | last3 = Nakamura | first3 = T. | last4 = Shimoura | first4 = S. | title = Two-particle correlations in continuum dipole transitions in Borromean nuclei | journal = [[Physical Review C]] | date = 2009 | volume = 80 | issue = 3 | page = 1301 | arxiv = 0904.4775 | bibcode = 2009PhRvC..80c1301H | doi = 10.1103/PhysRevC.80.031301 | s2cid = 119293335 }}</ref> A system made up of only two neutrons is not bound, though the attraction between them is very nearly enough to make them so.<ref>{{cite journal | last1 = MacDonald | first1 = J. | last2 = Mullan | first2 = D. J. | date = 2009 | title = Big Bang Nucleosynthesis: The Strong Nuclear Force meets the Weak Anthropic Principle | journal = [[Physical Review D]] | volume = 80 | issue = 4 | page = 3507 | arxiv = 0904.1807 | bibcode = 2009PhRvD..80d3507M | doi = 10.1103/PhysRevD.80.043507 | s2cid = 119203730 }}</ref> This has some consequences on [[nucleosynthesis]] and the [[abundance of the chemical elements]].<ref name="Bertulani 1993 281–376"/><ref>{{cite journal | last1 = Kneller | first1 = J. P. | last2 = McLaughlin | first2 = G. C. | author2-link = Gail McLaughlin | title = The Effect of Bound Dineutrons upon BBN | journal = [[Physical Review D]] | date = 2004 | volume = 70 | issue = 4 | page = 3512 | arxiv = astro-ph/0312388 | bibcode = 2004PhRvD..70d3512K | doi = 10.1103/PhysRevD.70.043512 | s2cid = 119060865 }}</ref>


A trineutron state consisting of three bound neutrons has not been detected, and is not expected to be bound.<ref>{{cite journal |title=Ab initio no-core Gamow shell-model calculations of multineutron systems |first1=J. G. |last1=Li |first2=N. |last2=Michel |first3=B. S. |last3=Hu |first4=W. |last4=Zuo |first5=F. R. |last5=Xu |journal=Physical Review C |volume=100 |issue= 5|date=2019 |page=054313 |doi=10.1103/PhysRevC.100.054313 |arxiv=1911.06485|bibcode=2019PhRvC.100e4313L }}</ref>
A trineutron state consisting of three bound neutrons has not been detected, and is not expected to be bound.<ref>{{cite journal |title=Ab initio no-core Gamow shell-model calculations of multineutron systems |first1=J. G. |last1=Li |first2=N. |last2=Michel |first3=B. S. |last3=Hu |first4=W. |last4=Zuo |first5=F. R. |last5=Xu |journal=Physical Review C |volume=100 |issue= 5|date=2019 |article-number=054313 |doi=10.1103/PhysRevC.100.054313 |arxiv=1911.06485|bibcode=2019PhRvC.100e4313L }}</ref>


A [[tetraneutron]] is a hypothetical particle consisting of four bound neutrons. Reports of its existence have not been replicated.<ref>{{cite journal | last1 = Bertulani | first1 = C. A. | last2 = Zelevinsky | first2 = V. | year = 2003 | title = Is the tetraneutron a bound dineutron-dineutron molecule? | journal = [[Journal of Physics G]] | volume = 29 | issue = 10 | pages = 2431–2437 | arxiv = nucl-th/0212060 | bibcode = 2003JPhG...29.2431B | doi = 10.1088/0954-3899/29/10/309 | s2cid = 55535943 }}</ref><ref>[https://scitechdaily.com/tetra-neutron-experiment-understanding-of-nuclear-forces-might-have-to-be-significantly-changed/ "Tetra-Neutron Experiment: Understanding of Nuclear Forces Might Have To Be Significantly Changed"]. {{Webarchive|url=https://web.archive.org/web/20211213090609/https://scitechdaily.com/tetra-neutron-experiment-understanding-of-nuclear-forces-might-have-to-be-significantly-changed/ |date=2021-12-13 }}. SciTechDaily, December 12, 2021. Technical University of Munich (TUM)</ref>
A [[tetraneutron]] is a hypothetical particle consisting of four bound neutrons. Reports of its existence have not been replicated.<ref>{{cite journal | last1 = Bertulani | first1 = C. A. | last2 = Zelevinsky | first2 = V. | year = 2003 | title = Is the tetraneutron a bound dineutron-dineutron molecule? | journal = [[Journal of Physics G]] | volume = 29 | issue = 10 | pages = 2431–2437 | arxiv = nucl-th/0212060 | bibcode = 2003JPhG...29.2431B | doi = 10.1088/0954-3899/29/10/309 | s2cid = 55535943 }}</ref><ref>[https://scitechdaily.com/tetra-neutron-experiment-understanding-of-nuclear-forces-might-have-to-be-significantly-changed/ "Tetra-Neutron Experiment: Understanding of Nuclear Forces Might Have To Be Significantly Changed"]. {{Webarchive|url=https://web.archive.org/web/20211213090609/https://scitechdaily.com/tetra-neutron-experiment-understanding-of-nuclear-forces-might-have-to-be-significantly-changed/ |date=2021-12-13 }}. SciTechDaily, December 12, 2021. Technical University of Munich (TUM)</ref>

Latest revision as of 15:16, 29 September 2025

Template:Short description

Neutronium (or neutrium,[1] neutrite,[2] or element zero) is a hypothetical substance made purely of neutrons. The word was coined by scientist Andreas von Antropoff in 1926 (before the 1932 discovery of the neutron) for the hypothetical "element of atomic number zero" (with no protons in its nucleus) that he placed at the head of the periodic table (denoted by -).[3][4] However, the meaning of the term has changed over time, and from the last half of the 20th century onward it has been also used to refer to extremely dense substances resembling the neutron-degenerate matter theorized to exist in the cores of neutron stars.

In neutron stars

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File:Neutron star cross section.svg
Cross-section of neutron star. Here, the core has neutrons or neutron-degenerate matter and quark matter.

Neutronium is used in popular physics literature[1][2] to refer to the material present in the cores of neutron stars (stars which are too massive to be supported by electron degeneracy pressure and which collapse into a denser phase of matter). In scientific literature the term "neutron-degenerate matter"[5] or simply neutron matter is used for this material.[6]

Hypothetical multi-neutrons

The term "neutronium" was coined in 1926 by Andreas von Antropoff for a conjectured form of matter made up of neutrons with no protons or electrons, which he placed as the chemical element of atomic number zero at the head of his new version of the periodic table.[3] It was subsequently placed in the middle of several spiral representations of the periodic system for classifying the chemical elements, such as those of Charles Janet (1928), Edgar Emerson (1944),[7][8] and John D. Clark (1950).

Script error: No such module "anchor".The term is not used in the scientific literature either for a condensed form of matter, or as an element, and theoretical analysis expects no bound forms of neutrons without protons.[9]

Scattering resonances with multiple neutrons

The dineutron, containing two neutrons, is not a stable bound particle, but an extremely short-lived resonance state produced by nuclear reactions in the decay of beryllium-16. Evidence reported in 2012 for the resonance[10][11] was disputed,[12] but new work reportedly clears up the issues.[13]

The dineutron hypothesis had been used in theoretical studies of the structure of exotic nuclei. For example 11Li is modeled as a dineutron bound to a 9Li core.[14][15] A system made up of only two neutrons is not bound, though the attraction between them is very nearly enough to make them so.[16] This has some consequences on nucleosynthesis and the abundance of the chemical elements.[14][17]

A trineutron state consisting of three bound neutrons has not been detected, and is not expected to be bound.[18]

A tetraneutron is a hypothetical particle consisting of four bound neutrons. Reports of its existence have not been replicated.[19][20]

Calculations indicate that the hypothetical pentaneutron state, consisting of a cluster of five neutrons, would not be bound.[21]

See also

References

Template:Reflist

Template:Periodic table (navbox) Template:Neutron star Template:Portal bar

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  5. ↑ Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "Citation/CS1".
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  8. ↑ Script error: No such module "Citation/CS1".
  9. ↑ Script error: No such module "Citation/CS1".
  10. ↑ Script error: No such module "Citation/CS1".
  11. ↑ Script error: No such module "Citation/CS1".
  12. ↑ Marqués, F. M., Orr, N. A., Achouri, N. L., Delaunay, F., & Gibelin, J. (2012). Comment on "First Observation of Ground State Dineutron Decay: Be 16". Physical Review Letters, 109(23), 239201.
  13. ↑ Script error: No such module "Citation/CS1".
  14. ↑ a b Script error: No such module "Citation/CS1".
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "Citation/CS1".
  17. ↑ Script error: No such module "Citation/CS1".
  18. ↑ Script error: No such module "Citation/CS1".
  19. ↑ Script error: No such module "Citation/CS1".
  20. ↑ "Tetra-Neutron Experiment: Understanding of Nuclear Forces Might Have To Be Significantly Changed". Template:Webarchive. SciTechDaily, December 12, 2021. Technical University of Munich (TUM)
  21. ↑ Script error: No such module "Citation/CS1".
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