Problem 1 · Big Five
DISSOLVEDDark matter identity
What's wrong (standard view): 26% undetected. WIMP null.
The standard view
Twenty-six per cent of the universe is missing
The standard cosmological model — ΛCDM — fits CMB acoustic peaks, baryon acoustic oscillations, galactic rotation curves, cluster dynamics and gravitational lensing by adding a non-baryonic matter component to the energy budget. That component is about 26% of the total. None of it has ever been seen in a detector.
Direct-detection experiments (XENON-nT, LUX-ZEPLIN, PandaX) have been running for a decade. They have ruled out cross-sections two orders of magnitude below the theoretically attractive WIMP region. Indirect detection (Fermi-LAT, IceCube, AMS) finds no clean signal. Collider searches at the LHC have produced no missing-energy excess. Sterile-neutrino searches are tightening. Axion searches continue.
The fact remains: every gravitational measurement says something is there; every particle-physics measurement says it is not.
The ISST view
It is not a missing particle. It is a missing factor of (1+f)
ISST does not introduce new matter. It reweights the matter we already know about. The matter Lagrangian carries a multiplicative coupling (1+f) where f = (1+fp)(1+fs) − 1. The primordial piece fp is built up over four Standard Model freezeouts in the early universe — electroweak, QCD hadronisation, pion+muon decoupling, e⁺e⁻ annihilation — and is finished well before BBN. The structural piece fs depends on the processing history of the matter being weighed.
The cosmological-mean prediction is (1 + fp) Ωb = Ωm. With fp = 5.66 ± 0.12 from Standard-Model degree-of-freedom freezeout, this gives 0.329 versus Planck's Ωm = 0.3153 — a 4.2% overshoot, 1.6–1.8σ tension. The residual is reported as honest uncertainty in the sharp-transition approximation; it is not absorbed into the model. There is no new particle species and no second contribution beyond the (1+f) coupling on baryons.
Caveat
The chain from the action's KL functional to the discrete fp sum has a specific structural obstruction (single-epoch vs path-additive). The value 5.66 is Standard-Model-motivated, not derived from the action. The paper specifies the assumptions and the open gap; this site flags it explicitly.
The mechanism
One scalar field, two roles
The full action is the single object that everything else derives from:
Ψ is the scalar field that sets the gravitational strength: an old universe (a universe with a long processing history) has a large Ψ and a weak gravitational coupling, so G = 1/Ψ. Matter we know about — protons, neutrons, electrons, photons — couples through (1+f) ℒm; the coupling is not constant across the universe because fs tracks structure.
The crucial property: Ψ does not propagate as a free degree of freedom. That is why ISST is not Brans-Dicke and not DEF: there is no extra polarisation in the gravitational waves you would detect at LIGO, no fifth-force constraint to dodge in the solar system. The trace equation reads and the post-Newtonian γ comes out exactly 1.
Above: a typical galaxy rotation curve (SPARC NGC 3198 schematic). The luminous-mass prediction (steel blue) falls off as Keplerian. The standard ΛCDM fit (slate) requires a dark-matter halo. ISST's (1+f)-modified Poisson equation (amber) reproduces the observed flat curve with no dark-matter halo and no MOND-style interpolation.
What would prove this wrong
The kill conditions
- A direct-detection experiment finds a real WIMP, axion, or sterile-neutrino signal at a cross-section consistent with ΛCDM's required relic density.
- A laboratory measurement shows that two equal-mass samples with different information content fall identically (no fs effect).
- LIGO/Virgo/KAGRA detect a propagating scalar polarisation in gravitational waves (Ψ becoming dynamical at high frequency).
- The galaxy rotation-curve fits driven by (1+f) systematically fail across the SPARC sample beyond the calibration set.