#

    CnuB temperature test

    This test checks that in the universe filled with photons, neutrons, protons, electrons and neutrinos (which decouple at temperatures around :

    • is not conserved by a factor around 1.401 in presence of additional species

    At temperatures electron-positron pairs annihilate, effectively disappearing from the plasma. This leads to increasing of the entropy and plasma temperature approximately 1.401 times.

    Log file

    import os
from particles import Particle
from evolution import Universe
from common import Params, UNITS
from library.SM import particles as SMP


folder = os.path.split(__file__)[0]

params = Params(T=10 * UNITS.MeV,
                dy=0.0125)
T_final = 0.0008 * UNITS.MeV


Particles = []
photon = Particle(**SMP.photon)
neutron = Particle(**SMP.hadrons.neutron)
proton = Particle(**SMP.hadrons.proton)
neutrino_e = Particle(**SMP.leptons.neutrino_e)
neutrino_mu = Particle(**SMP.leptons.neutrino_mu)
neutrino_tau = Particle(**SMP.leptons.neutrino_tau)
electron = Particle(**SMP.leptons.electron)
muon = Particle(**SMP.leptons.muon)
tau = Particle(**SMP.leptons.tau)

Particles += [
    photon,
    neutron,
    proton,
    neutrino_e,
    neutrino_mu,
    neutrino_tau,
    electron,
    muon,
    tau
]

universe = Universe(params=params, folder=folder)
universe.add_particles(Particles)
universe.init_kawano(electron=electron, neutrino=neutrino_e)

T_final = 1 * UNITS.MeV
universe.evolve(T_final, export=False)
T_final = 0.0008 * UNITS.MeV
params.dy = 0.025
universe.evolve(T_final)

print """
    Cosmic photon background temperature is {:.3f} times bigger than cosmic neutrinos temperature.
    Relative error is {:.3f} %
    """.format(universe.params.aT / UNITS.MeV,
               (universe.params.aT / UNITS.MeV - 1.401) / 1.401 * 100)