# n84 — dark matter and the audited vacuum (2026-07-09)
# Three replacement attempts, buried preemptively; one survivor that
# explains a thing dark matter only parametrizes.

## The three attempts that die on arrival (buried before anyone asks)
- ATTEMPT 1, the pump halo: the audit works hardest where fields are
  strong; if pump energy density ~ |grad Phi| (Landauer work x
  flux-driven event rate), the halo is exactly isothermal and rotation
  curves come out flat. IT DIES IN FIVE LINES: the flat velocity obeys
  v^2 ~ G^2 M, so v^4 ~ M^2 — the baryonic Tully-Fisher relation
  (v^4 ~ M, exquisitely measured) kills it by a full power. Buried.
- ATTEMPT 2, the activity halo at the Bullet cluster: pump energy
  tracks audit activity, i.e. ALL matter — and most baryonic mass is
  the GAS, which stalls in the collision. The lensing excess rides
  with the galaxies, on the other side. Wrong side of the Bullet.
  Buried.
- ATTEMPT 3, the third acoustic peak: any vacuum-metabolic density
  tied to local matter activity is baryon-tracking before
  recombination — precisely what the third peak excludes. Buried.
Together with n61's measured audit-rate invariance of the mean force
(no MOND), the conclusion is now FOUR ways forced and is upgraded from
absence to structure: THIS FRAMEWORK CANNOT FAKE DARK MATTER.
If the framework is right, dark matter is REAL MATTER — a genuine
prediction, not a resignation.

## The survivor: dark matter must carry the neutral residual
In the framework, all matter lives on the substrate and the EM sector
assigns every consumer a parity charge. Dark matter is electrically
dark: it must be built of PARITY-NEUTRAL composites. And neutral
composites do not interact with nothing — they interact through the
MEASURED residual channel: the short-range, parity-oscillating
r^-3.5 force (n69-E5, measured), the vacuum's own van der Waals.
CONSEQUENCE, registered: dark matter in this framework is
SELF-INTERACTING BY NECESSITY, with a short-range cross-section whose
shape (not scale — units owed, as ever) is already measured in the
toy.

## What that explains that "dark matter" alone does not
The CORE-CUSP problem: collisionless CDM predicts cuspy halo centers;
observed dwarf galaxies show cores. The standard fix is
self-interacting dark matter with sigma/m ~ 0.1-1 cm^2/g — inserted
by hand, tuned to fit. Here the self-interaction is NOT optional and
NOT tuned: every electrically-dark composite on the substrate carries
the residual channel. The framework turns SIDM from a model choice
into a STRUCTURAL NECESSITY, with two falsifiable signatures beyond
generic SIDM:
 (i) the interaction is SHORT-RANGE with the measured r^-3.5 envelope
     and parity oscillation — at astrophysical velocities this gives
     a mildly velocity-dependent cross-section (softer at high v),
     which is exactly the direction the data prefer (clusters need
     less self-interaction than dwarfs — observed);
 (ii) the SAME residual acts between dark and ordinary NEUTRAL matter
     (neutrons, atoms): a dark-visible short-range coupling at the
     same strength class — a fifth-force-style target with a named
     shape, invisible to charged-probe experiments.

## Honesty line
The survivor rests on: the measured residual (n69-E5), the parity
assignment of the EM reading (A-EM lineage), and the units gap (the
cross-section SCALE is not predicted — the shape and the necessity
are). The three burials rest on Tully-Fisher, the Bullet, and the
third peak — data. Kill conditions: dark matter shown to be exactly
collisionless at dwarf scales (sigma/m < 1e-2 cm^2/g robustly) kills
the necessity claim and with it the parity assignment of dark matter;
core-cusp resolved entirely by baryonic feedback with collisionless
DM would defang it to a consistency. No knee, no house — as ever.