2005/10/04 by G. Zaharijaš, Gabrijela Zaharijas, Zaharijas, Gabrijela
Physics and Astronomy · #Astrophysics (astro-ph) #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #Particle physics theoretical and experimental studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0510088
PhD Thesis, 137 pages
arxiv created 2005/10/04 · openalex publication_date 2005/10/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the dark matter problem with particular reference to a candidate particle within the Standard Model: the H dibaryon. We consider as well a scenario which aims to connect the dark matter origin to the Baryon Asymmetry of the Universe, studying the examples of H and of a BSM particle X. Strongly attractive color forces in the flavor singlet channel may lead to a tightly bound and compact H dibaryon. We find that the observation of Λ decays from doubly-strange hypernuclei puts a constraint on the H wavefunction which is plausibly satisfied. In this case the H is long-lived as we calculate. We also show that an H or another compact, flavor singlet hadron is unlikely to bind to nuclei, so that experimental bounds on exotic isotopes do not exclude their existence. Remarkably, the H appears to evade other experimental constraints as well, when account is taken of its expected compact spatial wavefunction. We check whether the H is a viable DM candidate by considering DM experiments sensitive to light particles. Taking into account the DM interaction in the crust above underground detectors we find a window in the exclusion limits in the micro-barn, m\lsi 2.4 GeV, range which coincides with the range expected for the tightly bound H. Finally, we present a scenario in which DM carries (anti-)baryon number and which offers a mechanism to generate the baryon asymmetry observed in the Universe. If σannih _X < σannihX, the X's freeze out at a higher temperature and have a larger relic density than X's. If mX \lsi 4.5 BX GeV and the annihilation cross sections differ by 10% or more, this type of scenario naturally explains the observed ΩDM ≃ 5 Ωb. Two examples are given, the H and an hypothetical BSM candidate X.