Motohiko Kusakabe, Tomohiro Takesako
Hypothetical long-lived massive colored particles (MCPs or Ys) would be
confined in colorless exotic strongly interacting massive particles (SIMPs) at
color confinement temperature of T_C /sim 200 MeV. Two long-lived MCPs form a
bound state (Y /bar{Y}) at collisions of two SIMPs. We study sensitivities of
MCP annihilation to decay properties of resonances (Y /bar{Y}), and binding
energies or energy levels of exotic SIMPs. The (Y /bar{Y}) formation is assumed
to dominantly proceeds through resonances of (Y/bar{Y}) in this paper. We make
a toy model of the effective cross section for Y /bar{Y} annihilation.
Abundances of SIMPs are then calculated for different sets of parameters
specifying properties of (Y /bar{Y}) resonances, binding energies of SIMPs, the
initial abundance and the mass of MCP. Calculated relic abundances for
respective SIMP species are 2 x 10^{-8}--3 x 10^{-4} times that of baryon. They
can be much higher but cannot be much smaller than the previous estimate. The
abundances can be consistent depending on parameters with the possible scenario
that SIMPs bind to nuclei and subsequent exotic nuclear reactions reduce the
primordial abundance of 7Li or enhance those of 9Be and/or B in the early
universe. A unique information on the quark-hadron phase transition in the
early universe may become available in future by elaborated studies on the
annihilation process with light element abundances as observables.
View original:
http://arxiv.org/abs/1112.0860
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