INTEGRAL maps 2 × 10⁴³ positron annihilations per second from the Galactic bulge, with a bulge-to-disk ratio no catalogued source population reproduces: the positron factories live in the disk while the 511 keV line concentrates in the bulge. Fifty years on, the source is unknown, MeV dark matter interpretations are cornered by laboratory and cosmological constraints, and conventional proposals each cover only part of the morphology.
The model's positron budget comes from its standard stellar inventory plus, optionally, a dark sector: when the inventory underpredicts the bulge, the dark sector beckons. The assumption that an anomalous bulge signal may trace the dark matter halo keeps a particle interpretation alive that every independent constraint disfavors.
SCT excludes the dark matter channel outright (P54): the positrons are astrophysical, and the framework's seeding history explains why the bulge outproduces its visible census. Collision seeding front-loaded the central galaxy with compact objects, black hole seeds and the dense first stellar generations (P46, P22), and the pre-existing matter context (P25) means the bulge carries the deepest recycling history in the galaxy: an old, rich population of millisecond pulsars, microquasar relics, and past accretion episodes of the central black hole, each a positron source whose integrated output the standard census, calibrated on the disk's younger inventory, undercounts. The bulge-to-disk anomaly is then demographic memory: the oldest, most processed stellar environment yields the most annihilation per unit starlight.
Propagation closes the morphology: MeV positrons diffuse and annihilate where gas and fields concentrate them, smearing the seeded-population output into the smooth bulge profile observed. No single dramatic source is required, and none should be found; the prediction is a composite origin resolving into the old compact-object census as instruments sharpen.
This is the same no-particle, deep-inventory reading behind the GeV excess and the diffuse backgrounds. There is no need to invoke MeV dark matter performing only in one line of one region.
The registered kill: a confirmed dark matter origin, the 511 keV morphology tracking a halo profile rather than stellar mass, or an MeV particle detected in the laboratory with the required couplings, would falsify SCT's universal null. The astrophysical reading is testable in the other direction: COSI mapping the line and finding it irreducible to the old compact-object census, with no correlation to bulge stellar mass or past activity tracers, would strain the demographic-memory account.