Dibaryons cannot be the dark matter

Abstract

The hypothetical $SU(3)$ flavor-singlet dibaryon state $S$ with strangeness $-2$ has been discussed as a dark-matter candidate capable of explaining the curious 5-to-1 ratio of the mass density of dark matter to that of baryons. We study the early-universe production of dibaryons and find that irrespective of the hadron abundances produced by the QCD quark/hadron transition, rapid particle reactions thermalized the $S$ abundance, and it tracked equilibrium until it "froze out" at a tiny value. For the plausible range of dibaryon masses (1860 - 1890 MeV) and generous assumptions about its interaction cross sections, $S$'s account for at most $10^{-11}$ of the baryon number, and thus cannot be the dark matter. Although it is not the dark matter, if the $S$ exists it might be an interesting relic.

11 pages, 5 figures

References in corpus (4)

• p-p, p-$\Lambda$ and $\Lambda$-$\Lambda$ correlations studied via femtoscopy in pp reactions at $\sqrt{s}$ = 7 TeV
• Six Flavor Quark Matter
• Dark Matter in the Standard Model?
• A Deeply Bound Dibaryon is Incompatible with Neutron Stars and Supernovae

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• The Scalar Hexaquark $uuddss$: a Candidate to Dark Matter?
• A new possibility for light-quark Dark Matter
• On the cosmology and terrestrial signals of sexaquark dark matter
• Thermal production of sexaquarks in heavy-ion collisions
• Running anomalous dimensions in holographic QCD: from the proton to the sexaquark
• Non-Thermal Production of Sexaquark Dark Matter