List of hypothetical particles

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This is a list of hypothetical particles.

Hypothetical particles are proposed subatomic or composite entities arising in theoretical particle physics and cosmology that have not been experimentally confirmed. They are typically introduced to address limitations of the Standard Model, unify fundamental interactions, or explain unresolved observations such as dark matter, neutrino masses, baryon asymmetry, or cosmic inflation. [1] [2] Many are mathematically well defined within quantum field theory or its extensions and serve as mediators or constituents in speculative but testable frameworks beyond the Standard Model. [3]

Contents

Prominent classes include gauge or symmetry-related particles such as the graviton or graviphoton in quantum gravity and extra-dimensional theories, and supersymmetric partners (e.g., neutralinos or charginos) predicted by supersymmetry. [4] [5] Others address specific phenomena, including hidden-sector bosons such as dark photons or light force carriers proposed to explain nuclear anomalies. [6]

Hypothetical particles also encompass predicted bound states (e.g., glueballs), topological objects such as magnetic monopoles, and unconventional statistical entities such as anyons or tachyons. [7] [8] Collectively, they form a central component of theoretical model building, guiding experimental searches for physics beyond currently known particles.

Elementary particles

Some theories predict the existence of additional elementary bosons and fermions that are not found in the Standard Model.

Hypothetical bosons and fermions
NameSpinNotes
axion
0
A pseudoscalar particle introduced in Peccei–Quinn theory to solve the strong-CP problem. [9]
dilaton
0
Predicted in some string theories. [10]
graviphoton
1
Also known as "gravivector". [11] It appears in Kaluza–Klein theory. [12]
graviton
2
Massless boson associated to gravitation. Included in many beyond the Standard Model theories. [13]
dual graviton
2
Has been hypothesized as dual of graviton under electric–magnetic duality in supergravity. [14]
graviscalar
0
Also known as "radion". It appears in Kaluza–Klein theory. [15]
hyperphoton
0
Hypothetical photon-like particle related to CP violations in kaon decay. [16] [17] [18]
inflaton
0
Unidentified scalar force-carrier that is presumed to have physically caused cosmic inflation. [19] [20] [21]
majoron
0
Predicted to understand neutrino masses by the seesaw mechanism. [22]
sterile neutrino
 1 /2
Right-handed neutrinos are compatible with the Standard Model but have never been observed. [23]
dual photon
1
Dual of the photon under electric–magnetic duality [24] [25] [26] [27] [28]
magnetic photon
1
Hypothetical particle similar to the photon in the presence of magnetic monopoles. [29]
pressuron
0
hypothetical scalar particle which couples to both gravity and matter theorized in 2013. [30]
symmetron
0
Mediates the fifth force of the hypothetical symmetron field. [31]
X and Y bosons
1
These leptoquarks are predicted by Grand Unified Theories to be heavier equivalents of the W and Z. [32]
W′ and Z′ bosons
1
Predicted by several extension of the electroweak interaction. [33]

Particles predicted by supersymmetric theories

Supersymmetry predicts the existence of superpartners to particles in the Standard Model, none of which have been confirmed experimentally. [34] The sfermions (spin is 0) include:

Squarks
NameSymbolSuperpartner ofSymbol
sup squark up quark
sdown squark down quark
scharm squark charm quark
sstrange squark strange quark
stop squark [35] top quark
sbottom squark bottom quark
Sleptons
NameSymbolSuperpartner ofSymbol
selectron electron
selectron sneutrino electron neutrino
smuon muon
smuon sneutrino muon neutrino
stau tau
stau sneutrino tau neutrino

Another hypothetical sfermion is the saxion, superpartner of the axion. It forms a supermultiplet, together with the axino and the axion, in supersymmetric extensions of Peccei–Quinn theory. [36]

The predicted bosinos (spin 12) are

Bosinos (superpartners of bosons)
Namesuperpartner of:Notes
axino axion Forms a supermultiplet, together with the saxion and axion, in supersymmetric extensions of Peccei–Quinn theory. [37]
dilatino dilaton Combines with the axion to form a complex scalar field [38]
gluino gluon Majorana fermions that interact via the strong force as a color octet.
gravitino graviton Predicted by supergravity (SUGRA).
higgsino Higgs boson For supersymmetry there is a need for several Higgs bosons, neutral and charged, according with their superpartners.
photino photon Mixing with zino and neutral Higgsinos for neutralinos.
gaugino (wino, zino) W and Z bosons The charged wino mixing with the charged Higgsino for charginos, for the zino see line above.

Just as the photon, Z and W± bosons are superpositions of the B0, W0, W1, and W2 fields, the photino, zino, and wino± are superpositions of the bino0, wino0, wino1, and wino2. No matter if one uses the original gauginos or this superpositions as a basis, the only predicted physical particles are neutralinos and charginos as a superposition of them together with the Higgsinos.

Other superpartner categories include:

Dark energy candidates

The following hypothetical particles have been proposed to explain dark energy:

NameDescription
Chameleon Couples to matter more weakly than gravity, with non-linear variable effective mass. [39] postulated as a dark energy candidate. [40]
Acceleron Particle that relates neutrino masses to dark energy. [41] [42] [43]
Quintessence particle Ultralight scalar boson whose vacuum expectation value evolves cosmologically; its coherent zero-momentum state produces negative pressure and late-time acceleration consistent with slowly rolling dark-energy models. [44] [45]
Phantom particleScalar boson with wrong-sign kinetic term yielding equation-of-state below −1; quantum excitations represent phantom dark energy causing super-accelerated expansion and possible future Big-Rip cosmology. [46] [47]
K-essence particleQuantum of a scalar with noncanonical kinetic structure; attractor dynamics drive cosmic acceleration without fine-tuned potential, behaving as effective vacuum energy at late times. [48] [49]
QuintaxionAxion-like pseudoscalar with extremely shallow periodic potential; misalignment energy evolves slowly and mimics quintessence, linking dark energy to Peccei–Quinn-type symmetries or string compactifications. [50] [51]
Ultralight axionAxion-like particle with mass near Hubble scale (~10⁻³³ eV); field remains frozen cosmologically so particle condensate behaves as nearly constant vacuum energy today. [52] [53]
String axionOne of many ultralight pseudoscalars predicted by string compactifications; lightest modes can remain overdamped until recent epochs, providing axion-like particle interpretation of dark-energy density. [54] [55]
Proca dark-energy bosonMassive vector boson with self-interaction potential; homogeneous temporal component acquires vacuum energy density, and particle excitations correspond to vector-dark-energy quanta driving acceleration. [56] [57]
Dark-energy vector bosonGeneral cosmic vector particle whose coherent background breaks Lorentz symmetry cosmologically; effective negative pressure arises from potential energy dominating kinetic contributions at late times. [58] [59]
Graviton condensate excitationCollective bosonic mode of a macroscopic graviton condensate; emergent quasiparticles encode vacuum energy of spacetime and can phenomenologically mimic cosmological-constant–like dark-energy behavior. [60] [61]

Dark matter candidates

The following categories are not unique or distinct: For example, either a WIMP or a WISP is also a FIP.

MeaningAbbreviationExplanationCandidates
Feebly interacting particle FIPParticles that interacts very weakly with conventional matter Massive gravitons
Gravitationally interacting massive particleGIMPMassive particles that only interact with matter gravitationally
Lightest supersymmetric particle LSPPredictions by supersymmetrySneutrino, gravitino, neutralino
Strongly interacting massive particle SIMPParticle that interact strongly between themselves and weakly with ordinary matter
Stable massive particles SMPLong-lived particle with appreciable mass
Weakly interacting massive particle WIMPHeavy particles that only interact with matter weakly neutralino, sterile neutrino
Weakly interacting slender particle WISPLight particles that only interact with matter weakly axion

Hidden sector theories have also proposed forces that only interact with dark matter, like dark photons.

From experimental anomalies

These hypothetical particles were claimed to be found or hypothesized to explain unusual experimental results. They relate to experimental anomalies but have not been reproduced independently or might be due to experimental errors (in chronological order):

Feynman diagram of a possible 750 GeV diphoton excess S750loops.svg
Feynman diagram of a possible 750 GeV diphoton excess
Fig. 6,7 from Prosper-Rene Blondlot: "Registration by Photography of the Action Produced by N Rays on a Small Electric Spark". Nancy, 1904. Blondlot N-rays.png
Fig. 6,7 from Prosper-René Blondlot: "Registration by Photography of the Action Produced by N Rays on a Small Electric Spark". Nancy, 1904.
NameDate of anomalyOriginator of the anomalyDetails
N-ray 1903 Prosper-René Blondlot An unknown form of radiation.
Oops-Leon 1976 Fermilab Resonance at 6 GeV
Valentine's day monopole1982 Blas Cabrera Navarro Single magnetic monopole detected on February 14, 1982. [62]
Meshugatron1989 Fleischmann–Pons experiment Predicted by Edward Teller in 1989 in an attempt to understand cold fusion claims [63]
Oh-My-God particle 1991 High Resolution Fly's Eye Cosmic Ray Detector 320 EeV cosmic ray, most energetic ultra-high-energy cosmic ray detected as of 2015
Leptoquark (B-anomaly)2012 Large Hadron Collider Hypothetical boson coupling quarks to leptons proposed to explain persistent flavor-universality violations in B-meson decays, notably RK and RD ratios, indicating potential new semileptonic interactions beyond Standard Model predictions. [64] [65]
Z′(Lμ−Lτ)2001 Brookhaven E821 Neutral gauge boson coupling to muon–tau lepton number difference proposed to explain muon anomalous magnetic-moment discrepancy and flavor anomalies while avoiding strong electron and quark coupling constraints. [66] [67]
750 GeV diphoton 2015Large Hadron ColliderResonance at 750 GeV signature of a bosonic particle
X17 particle 2015 ATOMKI Hypothesized new vector boson to explain nuclear experiments with beryllium.
Amaterasu particle 2021 Telescope Array Project 240 EeV cosmic ray

Others

By type

See also

References

  1. Griffiths, David J. (2008). Introduction to Elementary Particles (2nd ed.). Wiley-VCH.
  2. Cheng, Ta-Pei; Li, Ling-Fong (1984). Gauge Theory of Elementary Particle Physics. Oxford University Press.
  3. Peskin, Michael E.; Schroeder, Daniel V. (1995). An Introduction to Quantum Field Theory. Westview Press.
  4. Green, Michael B.; Schwarz, John H.; Witten, Edward (1987). Superstring Theory. Vol. 1. Cambridge University Press.
  5. Martin, Stephen P. (2016). A Supersymmetry Primer. Cambridge University Press.
  6. Holdom, Bob (1986). "Two U(1)'s and Epsilon Charge Shifts". Physics Letters B. 166: 196–198.
  7. 't Hooft, Gerard (1974). "Magnetic Monopoles in Unified Gauge Theories". Nuclear Physics B. 79: 276–284.
  8. Wilczek, Frank (1990). Fractional Statistics and Anyon Superconductivity. World Scientific.
  9. Peccei, R. D. (2008). "The Strong CP Problem and Axions". In Kuster, Markus; Raffelt, Georg; Beltrán, Berta (eds.). Axions: Theory, Cosmology, and Experimental Searches. Lecture Notes in Physics. Vol. 741. pp. 3–17. arXiv: hep-ph/0607268 . doi:10.1007/978-3-540-73518-2_1. ISBN   978-3-540-73517-5. S2CID   119482294.
  10. Bellazzini, B.; Csaki, C.; Hubisz, J.; Serra, J.; Terning, J. (2013). "A higgs-like dilaton". Eur. Phys. J. C. 73 (2): 2333. arXiv: 1209.3299 . Bibcode:2013EPJC...73.2333B. doi: 10.1140/epjc/s10052-013-2333-x . S2CID   118416422.
  11. Maartens, R. (2004). "Brane-world gravity" (PDF). Living Reviews in Relativity . 7 (1): 7. arXiv: gr-qc/0312059 . Bibcode:2004LRR.....7....7M. doi: 10.12942/lrr-2004-7 . PMC   5255527 . PMID   28163642.
  12. David Pollard, "Antigravity and classical solutions of five-dimensional Kaluza-Klein theory", J. Phys. A, 16, (1983), pp. 565-574, doi : 10.1088/0305-4470/16/3/015.
  13. Zyla, P.; et al. (Particle Data Group) (2020). "Review of Particle Physics: Gauge and Higgs bosons" (PDF). Progress of Theoretical and Experimental Physics. Archived (PDF) from the original on 2020-09-30.
  14. Curtright, T. (1985). "Generalised Gauge Fields". Physics Letters B . 165 (4–6): 304. Bibcode:1985PhLB..165..304C. doi:10.1016/0370-2693(85)91235-3.
  15. "Living Reviews in Relativity - Serial Profile - zbMATH Open". zbmath.org. Retrieved 2026-03-02.
  16. Bernstein, J.; Cabibbo, N.; Lee, T.D. (1964). "CP invariance and the 2π decay mode of the " (PDF). Physics Letters . 12 (2): 146–148. Bibcode:1964PhL....12..146B. doi:10.1016/0031-9163(64)91142-4. ISSN   0031-9163.
  17. Bell, J. S.; Perring, J. K. (1964-09-07). "2π Decay of the Meson". Physical Review Letters . 13 (10): 348–349. Bibcode:1964PhRvL..13..348B. doi:10.1103/physrevlett.13.348. ISSN   0031-9007.
  18. Phillips, Peter R. (1965-07-26). "New Tests for the Invariance of the Vacuum State Under the Lorentz Group". Physical Review . 139 (2B): B491–B494. Bibcode:1965PhRv..139..491P. doi:10.1103/physrev.139.b491. ISSN   0031-899X.
  19. Guth, Alan H. (1997). The Inflationary Universe: The quest for a new theory of cosmic origins . Basic Books. pp.  233–234. ISBN   978-0-2013-2840-0 via Internet Archive (archive.org).
  20. Steinhardt, Paul J.; Turok, Neil (2007). Endless Universe: Beyond the bang. Random House. p. 114. ISBN   978-0-7679-1501-4 via Google.
  21. Steinhardt, Paul J. (April 2011). "Inflation debate: Is the theory at the heart of modern cosmology deeply flawed?" (PDF). Scientific American . Archived from the original (PDF) on 2014-08-24. Retrieved 2013-12-31 via physics.princeton.edu.
  22. Lattanzi, M. (2008). "Decaying Majoron Dark Matter and Neutrino Masses". AIP Conference Proceedings . 966 (1): 163–169. arXiv: 0802.3155 . Bibcode:2008AIPC..966..163L. doi:10.1063/1.2836988. S2CID   14555177.
  23. "Sterile neutrinos". All things neutrino. Retrieved 2021-04-29.
  24. Bliokh, K. Y.; Bekshaev, A. Y.; Nori, F. (2013). "Dual electromagnetism: helicity, spin, momentum and angular momentum". New Journal of Physics . 15 (3) 033026. arXiv: 1208.4523 . Bibcode:2013NJPh...15c3026B. doi:10.1088/1367-2630/15/3/033026. S2CID   14501052.
  25. Elbistan, M.; Duval, C.; Horváthy, P. A.; Zhang, P.-M. (2016). "Duality and helicity: A symplectic viewpoint". Physics Letters B . 761: 265–268. arXiv: 1608.01131 . Bibcode:2016PhLB..761..265E. doi:10.1016/j.physletb.2016.08.041. S2CID   119176701.
  26. Elbistan, M.; Horváthy, P. A.; Zhang, P.-M. (2017). "Duality and helicity: the photon wave function approach". Physics Letters A . 381 (30): 2375–2379. arXiv: 1608.08573 . Bibcode:2017PhLA..381.2375E. doi:10.1016/j.physleta.2017.05.042. S2CID   119180293.
  27. Tong, D.; Lambert, N. (2008). "Membranes on an Orbifold". Physical Review Letters . 101 (4) 041602. arXiv: 0804.1114 . Bibcode:2008PhRvL.101d1602L. doi:10.1103/PhysRevLett.101.041602. PMID   18764318. S2CID   655777.
  28. Bakas, I. (2010). "Dual photons and gravitons". Publ.Astron.Obs.Belgrade. 88: 113–132. arXiv: 0910.1739 . Bibcode:2010POBeo..88..113B.
  29. Kühne, Rainer W. (1997). "A Model of Magnetic Monopoles". Modern Physics Letters A. 12 (40): 3153–3159. arXiv: hep-ph/9708394 . Bibcode:1997MPLA...12.3153K. doi:10.1142/S0217732397003277. S2CID   204007639.
  30. Minazzoli, O.; Hees, A. (August 2013). "Intrinsic Solar System decoupling of a scalar–tensor theory with a universal coupling between the scalar field and the matter Lagrangian". Physical Review D. 88 (4) 041504. arXiv: 1308.2770 . Bibcode:2013PhRvD..88d1504M. doi:10.1103/PhysRevD.88.041504. S2CID   119153921.
  31. "Space Has Invisible Walls Created by Mysterious 'Symmetrons,' Scientists Propose". 10 May 2022.
  32. Ta-Pei Cheng; Ling-Fong Li (1983). Gauge Theory of Elementary Particle Physics. Oxford University Press. ISBN   0-19-851961-3.
  33. J. Beringer et al. (Particle Data Group) (2012). "Review of Particle Physics". Physical Review D . 86 (1) 010001. Bibcode:2012PhRvD..86a0001B. doi: 10.1103/PhysRevD.86.010001 . hdl: 10481/34377 .
  34. "Supersymmetry". CERN. Archived from the original on 2023-07-14. Retrieved 2023-09-11.
  35. Search For Pair Production of Stop Quarks Mimicking Top Event Signatures
  36. Moroi, Takeo; Mukaida, Kyohei; Nakayama, Kazunori; Takimoto, Masahiro (2013-05-02), Scalar Trapping and Saxion Cosmology, arXiv, doi:10.48550/arXiv.1304.6597, arXiv:1304.6597, retrieved 2026-03-03
  37. Abe, Nobutaka; Moroi, Takeo; Yamaguchi, Masahiro (2002). "Anomaly-Mediated Supersymmetry Breaking with Axion". Journal of High Energy Physics . 1 (1): 10. arXiv: hep-ph/0111155 . Bibcode:2002JHEP...01..010A. doi:10.1088/1126-6708/2002/01/010. S2CID   15280422.
  38. "dilatino in nLab". ncatlab.org. Retrieved 2026-03-04.
  39. Cho, Adrian (2015). "Tiny fountain of atoms sparks big insights into dark energy". Science. doi:10.1126/science.aad1653.
  40. Khoury, Justin; Weltman, Amanda (2004). "Chameleon cosmology". Physical Review D. 69 (4) 044026. arXiv: astro-ph/0309411 . Bibcode:2004PhRvD..69d4026K. doi:10.1103/PhysRevD.69.044026. S2CID   119478819.
  41. "New theory links neutrino's slight mass to accelerating universe expansion". sciencedaily.com. Archived from the original on 13 May 2008. Retrieved 2008-06-05.
  42. Kaplan, D.; Nelson, A.; Weiner, N. (2004). "Neutrino oscillations as a probe of dark energy". Physical Review Letters . 93 (9) 091801. arXiv: hep-ph/0401099 . Bibcode:2004PhRvL..93i1801K. doi:10.1103/PhysRevLett.93.091801. PMID   15447091. S2CID   8861027.
  43. Fardon, R.; Nelson, A.; Weiner, N. (2004). "Dark energy from mass varying neutrinos". Journal of Cosmology and Astroparticle Physics . 2004 (10): 005. arXiv: astro-ph/0309800 . Bibcode:2004JCAP...10..005F. doi:10.1088/1475-7516/2004/10/005. S2CID   250827123.
  44. Ratra, B.; Peebles, P. J. E. (1988). "Cosmological consequences of a rolling homogeneous scalar field". Physical Review D 37: 3406–3427. doi:10.1103/PhysRevD.37.3406.
  45. Caldwell, R. R.; Dave, R.; Steinhardt, P. J. (1998). "Cosmological imprint of an energy component with general equation of state". Physical Review Letters 80: 1582–1585. doi:10.1103/PhysRevLett.80.1582.
  46. Caldwell, R. R. (2002). "A phantom menace? Cosmological consequences of a dark energy component with super-negative equation of state". Physics Letters B 545: 23–29. doi:10.1016/S0370-2693(02)02589-3.
  47. Carroll, S. M.; Hoffman, M.; Trodden, M. (2003). "Can the dark energy equation-of-state parameter w be less than −1?" Physical Review D 68: 023509. doi:10.1103/PhysRevD.68.023509.
  48. Armendáriz-Picón, C.; Mukhanov, V.; Steinhardt, P. J. (2000). "Dynamical solution to the problem of a small cosmological constant and late-time cosmic acceleration". Physical Review Letters 85: 4438–4441. doi:10.1103/PhysRevLett.85.4438.
  49. Armendáriz-Picón, C.; Mukhanov, V. (1999). "k-inflation". Physics Letters B 458: 209–218. doi:10.1016/S0370-2693(99)00603-6.
  50. Kim, J. E.; Nilles, H. P. (2003). "The μ problem and the strong CP problem". Physics Letters B 553: 1–6. doi:10.1016/S0370-2693(02)03126-9.
  51. Choi, K. (2000). "String or M theory axion as a quintessence". Physical Review D 62: 043509. doi:10.1103/PhysRevD.62.043509.
  52. Arvanitaki, A.; Dimopoulos, S.; Dubovsky, S.; Kaloper, N.; March-Russell, J. (2010). "String axiverse". Physical Review D 81: 123530. doi:10.1103/PhysRevD.81.123530.
  53. Visinelli, L.; Gondolo, P. (2019). "Dark matter axions revisited". Physical Review D 80: 035024. doi:10.1103/PhysRevD.80.035024.
  54. Svrček, P.; Witten, E. (2006). "Axions in string theory". Journal of High Energy Physics 2006(06): 051. doi:10.1088/1126-6708/2006/06/051.
  55. Arvanitaki, A.; Dimopoulos, S.; Dubovsky, S.; Kaloper, N.; March-Russell, J. (2010). "String axiverse". Physical Review D 81: 123530. doi:10.1103/PhysRevD.81.123530.
  56. Heisenberg, L. (2014). "Generalization of the Proca action". Journal of Cosmology and Astroparticle Physics 2014(05): 015. doi:10.1088/1475-7516/2014/05/015.
  57. De Felice, A.; Heisenberg, L.; Tsujikawa, S. (2016). "Cosmology of generalized Proca theories". Physical Review D 93: 104016. doi:10.1103/PhysRevD.93.104016.
  58. Koivisto, T. S.; Mota, D. F. (2008). "Vector field models of inflation and dark energy". Journal of Cosmology and Astroparticle Physics 2008(08): 021. doi:10.1088/1475-7516/2008/08/021.
  59. Beltrán Jiménez, J.; Koivisto, T. S. (2009). "Spacetimes with vector distortion: Inflation from generalised Weyl geometry". Physics Letters B 682: 114–121. doi:10.1016/j.physletb.2009.10.039.
  60. Dvali, G.; Gómez, C. (2013). "Black hole’s quantum N-portrait". Fortschritte der Physik 61: 742–767. doi:10.1002/prop.201300001.
  61. Dvali, G.; Gómez, C. (2014). "Quantum compositeness of gravity: Black holes, AdS and inflation". Journal of Cosmology and Astroparticle Physics 2014(01): 023. doi:10.1088/1475-7516/2014/01/023.
  62. Brumfiel, Geoff (2004-05-01). "The waiting game". Nature. 429 (6987): 10–11. doi:10.1038/429010a. ISSN   1476-4687. PMID   15129249.
  63. Huizenga, John R. (John Robert) (1992). Cold fusion : the scientific fiasco of the century. Internet Archive. Rochester, N.Y., U.S.A. : University of Rochester Press. ISBN   978-1-878822-07-9.
  64. LHCb Collaboration (2014). "Test of lepton universality using B⁺→K⁺ℓ⁺ℓ⁻ decays". Physical Review Letters 113: 151601. doi:10.1103/PhysRevLett.113.151601.
  65. Hiller, G.; Schmaltz, M. (2014). "RK and future b→sℓℓ physics beyond the Standard Model". Physical Review D 90: 054014. doi:10.1103/PhysRevD.90.054014.
  66. Altmannshofer, W.; Gori, S.; Pospelov, M.; Yavin, I. (2014). "Neutrino trident production: A powerful probe of new physics with neutrino beams". Physical Review Letters 113: 091801. doi:10.1103/PhysRevLett.113.091801.
  67. Abi, B. et al. (Muon g−2 Collaboration) (2021). "Measurement of the positive muon anomalous magnetic moment". Physical Review Letters 126: 141801. doi:10.1103/PhysRevLett.126.141801.
  68. Lemaître, Georges (1946). L'Hypothèse de l'Atome Primitif[Hypothesis of the Primal Atom] (in French). Neuchâtel, Éditions du griffon. OCLC   9863653.
  69. Nuclear Physics in a Nutshell, C. A. Bertulani, Princeton University Press, Princeton, NJ, 2007, Chapter 1, ISBN   978-0-691-12505-3.
  70. Schewe, Phil (2008-05-29). "New Form of Artificial Radioactivity". Physics News Update (865 #2). Archived from the original on 2008-10-14.
  71. Raciti, G.; Cardella, G.; De Napoli, M.; Rapisarda, E.; Amorini, F.; Sfienti, C. (2008). "Experimental Evidence of 2He Decay from 18Ne Excited States". Phys. Rev. Lett. 100 (19) 192503: 192503–192506. Bibcode:2008PhRvL.100s2503R. doi:10.1103/PhysRevLett.100.192503. PMID   18518446.
  72. Lichtenberg, D. B.; Namgung, W.; Predazzi, E.; Wills, J. G. (1982-06-14). "Baryon Masses in a Relativistic Quark-Diquark Model" . Physical Review Letters. 48 (24): 1653–1656. doi:10.1103/PhysRevLett.48.1653. ISSN   0031-9007.
  73. Wheeler, J. A. (January 1955). "Geons". Physical Review . 97 (2): 511–536. Bibcode:1955PhRv...97..511W. doi:10.1103/PhysRev.97.511.
  74. Freedman, Daniel Z.; van Niewenhuizen, Peter (March 1985). "The Hidden Dimensions of Spacetime" . Scientific American. 252 (3): 74–81. doi:10.1038/scientificamerican0385-74.
  75. Levin, E. (1997). "Everything about reggeons. Part I: Reggeons in "soft" interaction". arXiv: hep-ph/9710546 .
  76. Łukaszuk, L.; Nicolescu, B. (1 October 1973). "A possible interpretation of pp rising total cross-sections". Lettere al Nuovo Cimento. 8 (7): 405–413. doi:10.1007/BF02824484. S2CID   122981407.
  77. Wang, Zhiyuan; Hazzard, Kaden R. A. (January 2025). "Particle exchange statistics beyond fermions and bosons". Nature. 637 (8045): 314–318. arXiv: 2308.05203 . Bibcode:2025Natur.637..314W. doi:10.1038/s41586-024-08262-7 . Retrieved 2025-01-19.
  78. "Mathematical methods point to possibility of particles long thought impossible". Rice University. Archived from the original on January 9, 2025. Retrieved 2025-01-19.