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IndisputableMonolith.Cosmology.EntropyPerPhoton

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Defines the standard-model bookkeeping constants for cosmological entropy density: photon, electron, and neutrino internal degrees of freedom, the 7/8 fermion weight, pre/post e⁺e⁻ annihilation g-factors, the (4/11) neutrino dilution cube, g_*s = 43/11, and ζ(3). Cosmologists deriving η_γ, N_eff, or T_ν/T_γ cite these as the MODEL layer. The module is definitional; identities such as dilutionCubed_eq and gStarS_eq are algebraic equalities, not deep proofs.

claimFix the internal dof $g_\gamma=2$, $g_e=4$, $g_\nu=6$, the fermion entropy weight $7/8$, and the effective counts $g_{\mathrm{before}}=2+\frac78(4+6)$, $g_{\mathrm{after}}=2+\frac78\cdot 6$. Set the dilution cube $(T_\nu/T_\gamma)^3=4/11$ and $g_{*s}=43/11$, and record $\zeta(3)=\sum_{n\ge1}n^{-3}$ as a summable series used in number-density integrals.

background

In early-universe thermodynamics the entropy density of a relativistic species is $s=(2\pi^2/45)g_{*s}T^3$, with $g_{*s}$ an effective count of bosonic and fermionic degrees of freedom. Photons contribute $g_\gamma=2$ (two helicities). Electrons and positrons together contribute $g_e=4$; three neutrino species (left-handed, plus antineutrinos) contribute $g_\nu=6$. Fermions enter with a weight $7/8$ relative to bosons because the Fermi–Dirac energy integral is $7/8$ of the Bose–Einstein one.

Before $e^+e^-$ annihilation the full relativistic content is $g_{\mathrm{before}}=g_\gamma+(7/8)(g_e+g_\nu)$; afterward only photons and neutrinos remain, so $g_{\mathrm{after}}=g_\gamma+(7/8)g_\nu$. Entropy conservation then forces the neutrino temperature to dilute relative to the photon bath by $(T_\nu/T_\gamma)^3=g_{\mathrm{after}}/g_{\mathrm{before}}=4/11$, and the present-day $g_{*s}$ becomes $43/11$. The Riemann value $\zeta(3)$ appears in the number-density integrals that convert energy densities into particle counts per photon.

This module records those constants as MODEL inputs. Downstream modules discharge the $7/8$ weight and the dilution law from series and FRW identities.

proof idea

Definition module: no substantive proofs. Constants gPhoton, gElectron, gNeutrino, and fermionWeight are numeric MODEL inputs. gBefore and gAfter are arithmetic combinations of those inputs. dilutionCubed_eq and gStarS_eq are one-line algebraic rewrites equating the named symbols to the rationals $4/11$ and $43/11$. zeta3 is the series $\sum n^{-3}$ with a summability certificate zeta3_summable imported from Mathlib.

why it matters in Recognition Science

This is the MODEL layer that every entropy-per-photon identity in the Cosmology stack imports. FermionWeight upgrades the bare fermionWeight = 7/8 input to the series identity $\eta(4)=(7/8)\zeta(4)$; FermionWeightIntegral lifts that to the thermodynamic Fermi–Dirac versus Bose–Einstein energy integrals. NumberDensityIntegral closes the $s=3$ number-density layer (including the $3/4$ fermion weight) that feeds entropyPerPhoton_eq_ratio. NeutrinoDilution turns dilutionCubed and gStarS into theorems $(T_\nu/T_\gamma)^3=4/11$ and $g_{*s}=43/11$ once comoving entropy conservation and the $1/a$ redshift law are discharged from the FRW continuity equation.

Without these named constants the later modules would have nowhere to attach their discharges. In the broader Recognition framework they sit in the cosmology bookkeeping that connects the eight-tick and $\phi$-ladder structure to observable $N_{\mathrm{eff}}$ and baryon-to-photon ratios, but the present file itself is pure Standard-Model thermodynamics.

scope and limits

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