Chapter 4 — Expansion History
The best black body spectrum ever observed in nature?
What is the Cosmic Microwave Background (CMB)?
It led to more matter than anti-matter in our universe.
What is baryogenesis? What is leptogenesis?
PV=Nkt
What is the ideal gas law?
What is dark matter?
46.5 Glyrs
What is the current size of the visible universe?
Interaction rate Gamma >> H (Hubble)
What is the condition for thermal equilibrium?
After this quarks only exist in mesons and baryons.
What is the QCD phase transition.
At T ∼ 1 MeV, t ∼ 1 s
What is time of decoupling of the neutrinos in the Cosmic Neutrino Background?
Light signals emitted today will never reach anything beyond it.
What is the event horizon?
A bound state of an odd number of quarks.
What is a baryon?
Particles (like neutrinos) stop interacting with the plasma and themselves.
What is freeze-out?
T_nu/T_gamma=(4/11)1/3
What is the ration of the neutrino temperature and the photon temperature after e± annihilation?
Recombination / Last scattering
What it the physical event that marks the release of the CMB photons?
A bound state of u quark and d anti-quark.
What is the pi+ meson?
106.75
What is the number of relativistic degrees of freedom from the standard model of particle physics at T>>100 GeV?
t ∝ 1/T2
What is the scaling of cosmic time as a function of temperature during radiation domination?
56.3 km/s/Mpc
What is asymptotic future value of the Hubble parameter for the LambdaCDM model?
17
What is the number of particles in the standard model of particle physics?
Standard Model particles become massive during this transition.
What is the QED phase transition?
It gives g⋆≈3.82, outside observational bounds.
What is the g⋆ value if there were a fourth neutrino?