Hexaquark

A dibaryon-type hexaquark. There are two constituent quarks for each of the three colour charges.

In particle physics hexaquarks are a large family of hypothetical particles, each particle consisting of six quarks or antiquarks of any flavours. Six constituent quarks in any of several combinations could yield a colour charge of zero; for example a hexaquark might contain either six quarks, resembling two baryons bound together (a dibaryon), or three quarks and three antiquarks.[1] Once formed, dibaryons are predicted to be fairly stable by the standards of particle physics. In 1977 Robert Jaffe proposed that a possibly stable H dibaryon with the quark composition udsuds could notionally result from the combination of two uds hyperons[2]

A number of experiments have been suggested to detect dibaryon decays and interactions. In the 1990s several candidate dibaryon decays were observed but they were not confirmed.[3][4][5]

There is a theory that strange particles such as hyperons [6] and dibaryons[7] could form in the interior of a neutron star, changing its mass–radius ratio in ways that might be detectable. Accordingly, measurements of neutron stars could set constraints on possible dibaryon properties.[8] A large fraction of the neutrons in a neutron star could turn into hyperons and merge into dibaryons during the early part of its collapse into a black hole . These dibaryons would very quickly dissolve into quark–gluon plasma during the collapse, or go into some currently unknown state of matter.

In 2014 a potential dibaryon was detected at the Jülich Research Center at about 2380 MeV. The particle existed for 10−23 seconds and was named d*(2380).[9]

See also

References

  1. ↑ Vijande, J.; Valcarce, A; Richard, J.-M. (25 November 2011). "Stability of hexaquarks in the string limit of confinement". Physical Review D. 85. arXiv:1111.5921v1. Bibcode:2012PhRvD..85a4019V. doi:10.1103/PhysRevD.85.014019.
  2. ↑ R. L. Jaffe (1977). "Perhaps a Stable Dihyperon?". Physical Review Letters. 38 (5): 195. Bibcode:1977PhRvL..38..195J. doi:10.1103/PhysRevLett.38.195.
  3. ↑ J. Belz et al. (BNL-E888 Collaboration) (1996). "Search for the weak decay of an H dibaryon". Physical Review Letters. 76: 3277–3280. arXiv:hep-ex/9603002. Bibcode:1996PhRvL..76.3277B. doi:10.1103/PhysRevLett.76.3277.
  4. ↑ R. W. Stotzer et al. (BNL-E836 Collaboration) (1997). "Search for H dibaryon in He-3 (K-, k+) Hn". Physical Review Letters. 78: 3646–36490. Bibcode:1997PhRvL..78.3646S. doi:10.1103/PhysRevLett.78.3646.
  5. ↑ A. Alavi-Harati et al. (KTeV Collaboration) (2000). "Search for the weak decay of a lightly bound H0 dibaryon". Physical Review Letters. 84: 2593–2597. arXiv:hep-ex/9910030. Bibcode:2000PhRvL..84.2593A. doi:10.1103/PhysRevLett.84.2593. PMID 11017277.
  6. ↑ V. A. Ambartsumyan; G. S. Saakyan (1960). "The Degenerate Superdense Gas of Elementary Particles". Soviet Astronomy. 37: 193. Bibcode:1960SvA.....4..187A.
  7. ↑ S. Kagiyama; A. Nakamura; T. Omodaka (1992). "Compressible bag model and dibaryon stars". Zeitschrift für Physik C. 56 (4): 557–560. Bibcode:1992ZPhyC..56..557K. doi:10.1007/BF01474728.
  8. ↑ A. Faessler; A. J. Buchmann; M. I. Krivoruchenko (1997). "Constraints to coupling constants of the ω- and σ-mesons with dibaryons". Physical Review C. 56: 1576. arXiv:nucl-th/9706080. Bibcode:1997PhRvC..56.1576F. doi:10.1103/PhysRevC.56.1576.
  9. ↑ P. Adlarson; et al. (2014). "Evidence for a New Resonance from Polarized Neutron-Proton Scattering". Physical Review Letters. 112 (2): 202301. arXiv:1402.6844. Bibcode:2014PhRvL.112t2301A. doi:10.1103/PhysRevLett.112.202301.
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