CHICAGO — An MQ analysis compares the difference between two operating modes of the 2026 NIST/BIPM gravitational-constant experiment with a fixed numerical target. In the copper configuration, free deflection exceeds electrostatic servo by 56.79 ± 29.43 parts per million. The MQ target is 34.93 parts per million in the same direction.

The contrast is normalized to the servo result. Its uncertainty is reconstructed from the paper’s primary combined uncertainties and mode correlation, rather than treating the two measurements as independent. Figure 1 distinguishes the observed difference, the fixed target and the two questions answered by their standardized differences.

The experiment was performed by Schlamminger and collaborators and published in Metrologia on April 16, 2026. Free-deflection operation reads the pendulum’s mechanical response; electrostatic servo holds its angle with a balancing electrical torque. Both modes measure the gravitational interaction. Their association with different MQ realization regimes is a subsequent interpretation.

The central copper difference lies 0.74 standard uncertainties above the MQ target and 1.93 above zero. These numbers describe different comparisons under the stated budget. They do not assign a probability that MQ is correct. The less precise sapphire configuration also has a positive central difference, 149.72 ± 92.01 ppm; the four determinations are correlated and must not be counted as independent confirmations.

The paper treats the mode offset as unexplained and introduces configuration-specific additional uncertainty when forming its final consensus. The primary-budget contrasts quoted here omit those additional terms. Neither material’s zero contrast lies outside its two-standard-uncertainty interval under this reconstruction, so the numerical comparison is not a discovery-level identification of new physics.

MQ’s broader numerical realization construction predates the 2026 result, while assigning these particular free-deflection and servo modes to the two MQ regimes was retrospective. Geiger reports no role in designing, conducting or analyzing the experimental campaign; the comparison presented here is his subsequent MQ analysis. Earlier correspondence does not establish influence or institutional endorsement.

For the combined gravitational constant, the published paper reports 6.67387 ± 0.00038, multiplied by 10⁻¹¹ m³ kg⁻¹ s⁻². This takes precedence over a different number in the publication-metadata abstract. The combined estimate and the within-material mode contrasts are distinct quantities.

The technical Brief provides all four mode values, the correlation matrix, the MQ target construction and a reproducible uncertainty calculation. It explains why instrumental effects remain viable and what a prospective experiment would need to distinguish.

# # #