QMU Registration of Gyroscopic Coupling in a Nonspinning Ferromagnet: Public-Trace Reproduction, a Composition Envelope, and a Material-Participation Constraint

Ahrens and Vinante recently measured gyroscopic spin-rotation coupling between two librational modes of a nonspinning, superconductively levitated hard-ferromagnet microsphere. The measured coupling provides a direct experimental relation between the magnetic moment μ and the collective intrinsic angular momentum S associated with the particle magnetization. This study independently reconstructs the central experimental observable from the complete public archive. All five deposited MD5 checksums are verified, and all 315 two-channel traces are analyzed using the correlation model specified in the experimental supplement. Three of the four reconstructed Einstein--de Haas frequencies fI agree with the published central values to within $0.3%$. Dataset 1, which contains the smallest measured quadrature ratio, reconstructs $17.4%$ above the published central value but remains consistent within $1.24$ combined standard deviations. An inverse-variance fit to the four published material factors gives gₘₐₜ=1.16263±0.02578, corresponding to Γₘₐₜ=gₘₐₜ/2=0.58131±0.01289. The size-scaling quantity fI R²/M is consistent with a common material factor across the four experimental configurations, with χ²=0.969 for three degrees of freedom and $p=0.809$ under the stated independence approximation. The experimental result is registered in Quantum Measurement Units using angm=h=mₑλC²Fq, magm=eₑmax²λC²Fq, mchg=mₑ/eₑmax², and ccf=eₑmax²/e. These definitions produce the exact correlations magm/angm=1/mchg and ccf\,mchg=mₑ/e. The resulting dimensionless QMU registration is ΓQMU=(μ\,ccf/magm)/(S/angm)=g/2=(μ\,ccf/S)mchg. For a spherical particle, the experimental closure becomes ΓQMU=5M\,ccf\,mchg/(4πρ R²fI)=5Mmₑ/(4πρ R²fIe). This expresses the measured gyroscopic coupling as a dimensionless ratio of magnetic moment and angular momentum while preserving an exact bridge to the experimentally reported quantities. Public composition reports for commercial Magnequench MQP-S-11-9-20001 powder are converted from weight percent to atomic percent and evaluated with the deliberately simplified constituent model used in the source study. The resulting composition controls give gctrl=1.3647--$1.3952$ and Γctrl=0.6823--$0.6976$. Within this model, agreement with the measured value requires the rare-earth share of modeled angular momentum to increase from approximately $0.48$--$0.50$ to approximately $0.661$. The equivalent transition-metal participation factor is βTM=0.468--$0.516$. The QMU identity ΓQMU=g/2 is an exact registration of the measured observable rather than an independent material prediction. A predictive Aether Physics Model calculation must determine the species- and phase-resolved magnetic-moment and angular-momentum population sums before comparison with the experiment. The paper therefore defines the numerical target, identifies the principal material-participation constraint, and proposes composition, phase, temperature, particle-metrology, and blind-registration experiments capable of distinguishing competing closures. The deposit includes the complete paper, Overleaf-compatible LaTeX source, publication figures, machine-readable result summaries, composition inputs, claims ledger, figure-regeneration code, and package-validation report.