Dibaryon

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H dibaryon.jpg

In particle physics dibaryons are a large family of hypothetical particles that would consist of six quarks of any flavours. They are predicted to be fairly stable once formed. Robert Jaffe proposed the existence of a possibly stable H dibaryon (with the quark composition udsuds), made by combining two uds hyperons, in 1977.[1]

A number of experiments have been suggested to detect dibaryon decays and interactions. Several candidate dibaryon decays were observed but not confirmed in the 1990s.[2][3][4]

There is a theory that strange particles such as hyperons [5] and dibaryons [6] could form in the interior of a neutron star, changing its mass–radius ratio in ways that might be detectable. Conversely, measurements of neutron stars set constraints on possible dibaryon properties.[7] Large fraction of neutrons could turn into hyperons and merge into dibaryons during the early part of a neutron star to black hole collapse[citation needed]. 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).[8]

See also[edit]

  • Deuteron, the only known stable composite particle that consist of six quarks.
  • Diproton, an extremely unstable dibaryon.
  • Dineutron, another extremely unstable dibaryon.

References[edit]

  1. ^ R.L. Jaffe (1977). "Perhaps a Stable Dihyperon?". Physical Review Letters 38 (5): 195. Bibcode:1977PhRvL..38..195J. doi:10.1103/PhysRevLett.38.195. 
  2. ^ BNL-E888 Collaboration (J. Belz et al.) "Search for the weak decay of an H dibaryon", Phys. Rev. Lett. 76:3277–3280 (1996) arXiv:hep-ex/9603002
  3. ^ BNL E836 Collaboration (R.W. Stotzer et al.) "Search for H dibaryon in He-3 (K-, k+) Hn", Phys. Rev. Lett. 78:3646–3649 (1997)
  4. ^ KTeV Collaboration (A. Alavi-Harati et al.) "Search for the weak decay of a lightly bound H0 dibaryon", Phys. Rev. Lett. 84:2593–2597 (2000), arXiv:/hep-ex/9910030
  5. ^ V. A. Ambartsumyan and G. S. Saakyan, Astron Zh. 37, 193 (1960).
  6. ^ Shigenori Kagiyama, Akihiro Nakamura and Toshihiro Omodaka; Compressible bag model and dibaryon stars; Zeitschrift für Physik C Particles and Fields; Volume 56, Number 4 / December, 1992
  7. ^ A. Faessler, A. J. Buchmann, M. I. Krivoruchenko, Constraints to coupling constants of the ω- and σ-mesons with dibaryons, Phys. Rev. C56, 1576 (1997) arXiv:nucl-th/9706080
  8. ^ "Evidence for a New Resonance from Polarized Neutron-Proton Scattering", http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.202301