neutrinosdominated

Neutrinosdominated is a term used in theoretical discussions to describe a state in which neutrinos make up the majority of the energy density or particle content in a region, due to high temperature, density, or neutrino trapping. In standard cosmology, neutrinos contribute to radiation density but do not dominate; neutrinosdominated scenarios typically require nonstandard physics or extreme environments.

Contexts include the interior of a proto-neutron star during early cooling, where neutrinos are trapped and carry most thermal energy and lepton number; core-collapse supernovae, where neutrino transport governs energy release; and speculative early-universe models with extra relativistic species or large lepton asymmetry that raise the neutrino energy density above photons.

Characteristics and implications: the equation of state and pressure are influenced by neutrino degeneracy and trapping; neutrino diffusion sets cooling and deleptonization timescales; nucleosynthesis can be affected. Observational signals include strong neutrino fluxes from supernovae and potential imprints on the expansion history in cosmology, constrained by measurements of N_eff from the CMB and big bang nucleosynthesis.

In practice, neutrinosdominated is not an established standard phase; it is used to describe or explore regimes in simulations where neutrino transport dominates energetics, and remains contingent on the underlying physics assumed in the model.