Primordial black hole formation during the QCD epoch
- Physics Research Program, Institute for Geophysics and Planetary Physics, University of California, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
We consider the formation of horizon-size primordial black holes (PBH{close_quote}s) from pre-existing density fluctuations during cosmic phase transitions. It is pointed out that the formation of PBH{close_quote}s should be particularly efficient during the QCD epoch due to a substantial reduction of pressure forces during adiabatic collapse, or equivalently, a significant decrease in the effective speed of sound during the color-confinement transition. Our considerations imply that for generic initial density perturbation spectra PBH mass functions are expected to exhibit a pronounced peak on the QCD-horizon mass scale {approximately}1M{sub {circle_dot}}. This mass scale is roughly coincident with the estimated masses for compact objects recently observed in our galactic halo by the MACHO Collaboration. Black holes formed during the QCD epoch may offer an attractive explanation for the origin of halo dark matter evading possibly problematic nucleosynthesis and luminosity bounds on baryonic halo dark matter. {copyright} {ital 1997} {ital The American Physical Society}
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 503778
- Journal Information:
- Physical Review, D, Vol. 55, Issue 10; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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