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Thermodynamics of the early Universe with mirror dark matter
Phys. Rev. D 78, 123003 – Published 10 December, 2008
DOI: https://doi.org/10.1103/PhysRevD.78.123003
Abstract
Mirror matter is a promising self-collisional dark matter candidate. Here we study the evolution of thermodynamical quantities in the early Universe for temperatures below in presence of a hidden mirror sector with unbroken parity symmetry and only with gravitational interactions. This range of temperatures is interesting for primordial nucleosynthesis analyses, therefore we focus on the temporal evolution of number of degrees of freedom in both sectors. Numerically solving the equations, we obtain the interesting prediction that the effective number of extra-neutrino families raises for decreasing temperatures before and after big bang nucleosynthesis; this could help solving the discrepancy in this number computed at nucleosynthesis and cosmic microwave background formation epochs.
Article Text
References (26)
- T. D. Lee and C.-N. Yang, Phys. Rev. 104, 254 (1956).
- R. Foot, H. Lew, and R. R. Volkas, Phys. Lett. B 272, 67 (1991).
There could be other interactions, as, for example, the kinetic mixing between ordinary and mirror photons [26], but they are very low, and are neglected in the present study.
- L. B. Okun, Phys. Usp. 50, 380 (2007).
- Z. Berezhiani, D. Comelli, and F. L. Villante, Phys. Lett. B 503, 362 (2001).
- P. Ciarcelluti, AIP Conf. Proc. 1038, 202 (2008).
- P. Ciarcelluti, Ph.D. thesis, University of Roma “Tor Vergata,” Italy, 2003, arXiv:astro-ph/0312607.
- Z. Berezhiani, P. Ciarcelluti, D. Comelli, and F. L. Villante, Int. J. Mod. Phys. D 14, 107 (2005).
- P. Ciarcelluti, Frascati Phys. Ser. 555, 1 (2004).
- P. Ciarcelluti, Int. J. Mod. Phys. D 14, 187 (2005).
- P. Ciarcelluti, Int. J. Mod. Phys. D 14, 223 (2005).
- A. Y. Ignatiev and R. R. Volkas, Phys. Rev. D 68, 023518 (2003).
- S. I. Blinnikov, arXiv:astro-ph/9801015.
- R. Foot, Phys. Lett. B 452, 83 (1999).
- R. N. Mohapatra and V. L. Teplitz, Phys. Lett. B 462, 302 (1999).
- Z. Berezhiani, S. Cassisi, P. Ciarcelluti, and A. Pietrinferni, Astropart. Phys. 24, 495 (2006).
- R. Foot, Phys. Rev. D 78, 043529 (2008).
- R. Bernabei et al. (DAMA), Eur. Phys. J. C 56, 333 (2008).
- Z. G. Berezhiani, A. D. Dolgov, and R. N. Mohapatra, Phys. Lett. B 375, 26 (1996).
From now on all particles and parameters of the mirror sector will be marked by to distinguish them from the ones related to the observable or ordinary world.
- G. Mangano, A. Melchiorri, O. Mena, G. Miele, and A. Slosar, J. Cosmol. Astropart. Phys. 03 (2007) 006.
- E. W. Kolb and M. S. Turner, The Early Universe, Frontiers in Physics Vol. 69 (Addison-Wesley, Redwood City, CA, 1990).
- T. Padmanabhan, Theoretical Astrophysics, Volume III: Galaxies and Cosmology (Cambridge University, Cambridge, England, 2002).
The assumption that the neutrino decoupling is an instantaneous process taking place when photons have the temperature introduces just a small error (), that is negligible for the precision required in this work.
For simplicity we write , , , and .
- R. Foot, A. Y. Ignatiev, and R. R. Volkas, Phys. Lett. B 503, 355 (2001).