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    Neutrino decoupling

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    Neutrino Decoupling: In the early Universe, electrons and neutrinos are strongly coupled through scattering (ν e ↔ ν e) and annihilation (ν ν¯ ↔ e e¯). (see attached files for defined parameters)
    (a) Find the redshift and temperature of neutrino decoupling.
    (b) After neutrino decoupling, the Universe is filled with a cosmic neutrino background. Assuming that all 3 species of neutrinos have a mass of mν = 1 eV, and that neutrinos follow a Maxwell Boltzmann distribution since they are currently non-relativistic, how many relic neutrinos are in a cubic meter?

    (see attached file for detailed problem)

    © BrainMass Inc. brainmass.com October 10, 2019, 7:59 am ad1c9bdddf
    https://brainmass.com/physics/cosmology/neutrino-decoupling-602888

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    Solution Summary

    Given the values of cosmological parameters observed or assumed today, we calculate the main source of opacity for neutrino collisions and calculate the age of neutrino decoupling.

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