HELIUM-4 Plateau Shift

The ΛCDM Tension

BBN predicts primordial He-4 mass fraction Y_p ≈ 0.2471 from baryon-to-photon ratio. High-precision observations of metal-poor extragalactic HII regions sometimes yield Y_p systematically offset from BBN predictions (Izotov 2014; Aver 2015; Kurichin 2021). ΛCDM struggles because BBN is cornerstone prediction; reconciling demands modifying neutrino species, neutron lifetime, expansion rate, or invoking unknown systematics.

The ΛCDM Assumption That Creates It

The standard model has BBN producing one universal Y_p value at standard baryon density and SM physics. Recovering observed Y_p plateau shifts demands either improved spectroscopy systematics or modifications to BBN inputs, neither of which is parsimonious within minimal ΛCDM.

SCT Resolution: M2 (Plasma Equivalence Theorem)

SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, SCT predicts Y_p plateau matches ΛCDM at Y_p = 0.2449 ± 0.0040 (recid 176, paper 4210). Cascade termination well before t ≈ 1 second (P40) leaves BBN to proceed at thermal equilibrium under standard SM thermodynamics (P42), reproducing the standard Y_p yield.

The Plasma Equivalence Theorem (P29, P30) ensures the post-cascade plasma reaches the same six-parameter thermodynamic state as ΛCDM. Cascade-thermalized + in-cycle helium variations from prior cycles are erased: the cascade temperatures above QCD scale destroy any prior nucleosynthesis baseline, so post-cascade BBN starts fresh from primordial composition (P25 supplies baryons but cascade thermalization erases prior helium structure).

Observed Y_p plateau shifts therefore reflect post-BBN stellar processing of helium plus systematic measurement uncertainties, not primordial-Y_p variations. The cascade-context (P22) gives heterogeneous host environments for the metal-poor HII regions, contributing to the apparent plateau scatter through different stellar-evolution histories. The same M2 framework that resolves the broader BBN family (recid 171, 176, 178, 179) accounts for Y_p plateau shifts as shared open issues with ΛCDM that require systematics resolution rather than unique SCT signatures.

Falsifier

If precision deep helium spectroscopy + BBN nuclear-rate measurements converge Y_p observations + predictions to better than 0.1% agreement, the tension is resolved (favoring neither ΛCDM nor SCT). If the tension persists or grows beyond systematics-induced expectations, both frameworks face the same challenge.

Premise Grounding

• P22: Physics of superluminal intersections, cascade-thermalization erases prior helium structure.
• P25: Pre-existing matter thermalized by collision, supplies baryons but not helium.
• P28: Eternal collision cycle, prior cycles do not supply Y_p across cascade events.
• P29: Thermodynamic state sufficiency, post-cascade plasma evolution governed by standard physics.
• P40: Cascade termination before t ≈ 1 second, BBN proceeds at thermal equilibrium.
• P42: BBN at thermal equilibrium, reproduces standard nucleosynthesis identically.