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arXiv · 1404.6005

Quark-Gluon Plasma as the Possible Source of Cosmological Dark Radiation

Jeremiah Birrell·Johann Rafelski
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Abstract

The effective number of neutrinos, $N_{\text{eff}}$, obtained from CMB fluctuations accounts for all effectively massless degrees of freedom present in the Universe, including but not limited to the three known neutrinos. Using a lattice-QCD derived QGP equation of state, we constrain the observed range of $N_{\text{eff}}$ in terms of the the freeze-out of unknown degrees of freedom near to quark-gluon hadronization. We explore limits on the coupling of these particles, applying methods of kinetic theory. We present bounds on the coupling of such particles and discuss the implications of a connection between $N_{\text{eff}}$ and the QGP transformation for laboratory studies of QGP.

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Jeremiah Birrell, Johann Rafelski. 2014-11-23. Quark-Gluon Plasma as the Possible Source of Cosmological Dark Radiation. https://doi.org/10.1016/j.physletb.2014.12.033

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