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BBN: light-element abundances vs baryon density

What you are seeing: the primordial 4^4He mass fraction YpY_p, deuterium-to-hydrogen ratio D/HD/H, and lithium-to-hydrogen ratio 7^7Li/H/H, all as a function of the baryon-to-photon ratio η10=1010nb/nγ\eta_{10} = 10^{10} n_b / n_\gamma.

Figure 1. Primordial light-element abundances vs η10\eta_{10}.
η₁₀6.10

WHAT TO TRY

  • Vary each control and watch the rail readouts respond.
  • Compare the diagnostic plot against the live scene.