Toward Predictive Galaxy-Cluster Dynamics without Dark Matter: Collective Vacuum Momentum Response from Three-Dimensional Baryonic Structure

Galaxy clusters are a demanding test for any theory in which the apparent gravitational excessis generated by the observed baryons themselves. We extend the collective vacuum momentumresponse (CVMR) framework developed for disk-galaxy rotation curves to approximately sphericalgalaxy clusters without introducing a cluster-specific normalization. The galaxy-calibrated sourcecoefficient and the matter-theory fivefold coupling bound are held fixed; only the transport geometry,three-dimensional baryonic distribution, and pressure-support readout change. A common forwardcalculation is applied to A1795, A2029, A85, and ZW1215. The first three systems remain broadlyconsistent with the required response over the tested radial range, whereas ZW1215 develops apronounced outer deficit. Rather than retuning the theory, we use that residual as a diagnostic.ZW1215 is structurally more diffuse than A2029, and its published mass reconstructions disagreestrongly. The cumulative mass profile corresponding to exact CVMR agreement lies within presentweak-lensing and galaxy-dynamical uncertainties but below the high hydrostatic branch. The fourclustertest therefore isolates two coupled requirements for a predictive cluster theory: sensitivityto three-dimensional baryonic structure and explicit control of mass-reconstruction systematics.