BU60 Effective-Theory Disqualification Criterion under B_U Microscopic Nonzero Bias, Same-World-Sheet Revocation, Global Catastrophe Chain, and Structured Cutoff of Backward-Mirror Theories

This paper develops BU60 as an effective-theory disqualification criterion under Single-Universe Boundary Consistency, B_U. Its central claim is that backward-mirror effective theories are not rejected in total; they are constrained by their effective domains. Inside a valid domain, defined by scale window, energy range, boundary condition, measurement resolution, approximation premise, and settlement condition, an effective theory can stand as a reliable projection-level tool. Its validity depends on the preservation of the same world-sheet: stable constants, repeatable readouts, closed local equations, consistent object boundaries, and reproducible experimental landing points. BU60 identifies microscopic zeroing and fast-slow orthogonality as the upstream conditions of that same world-sheet. At the ontic-audit level, the microscopic feedback average must be exactly zero; finite tolerance belongs only to measurement or numerical resolution, not to the underlying admissibility condition. Once a candidate theory permits a microscopic nonzero net item to enter the macroscopic ledger, it triggers background drift, constant drift, structural drift, and settlement drift. These drifts revoke the same world-sheet required for the theory’s own standing. The paper further clarifies that B_U itself does not rupture. Drift occurs inside the candidate theory’s boundary readout, and the candidate theory is structurally cut off when it cannot pass the D(M) audit. Conditional examples include string-theoretic, many-worlds, and loop-quantum-gravity readings only when they are interpreted as retaining microscopic net bias, multiple real boundary sheets, or independent micro-boundary granules. The final judgment is that BU60 is not anti-science. It preserves the tool value of effective theories inside their valid domains while disqualifying overshooting readings that revoke the cleared background, same world-sheet, and settlement conditions required for scientific standing.