BKT–40 Belle/Belle II Results Beyond a Scalar Fit of the Standard Model

BKT-40 presents an application of the orthogonal-residual and null-anchor apparatus to a concrete new-physics benchmark in the B⁺ → K⁺ + inv channel. The article focuses on a two-body invisible-residual hypothesis, B⁺ → K⁺X_inv, localized near m_X ≃ 2.10 GeV, which corresponds to q_X² ≃ 4.41 GeV². The benchmark point is based on the public model-agnostic likelihood reinterpretation of the Belle II B⁺ → K⁺νν̄ measurement. The article explicitly separates phenomenological calibration from the test prediction. The calibrated quantities are m_X and B(B⁺ → K⁺X)·P_X,inv, whereas the BKT-40 test concerns the frozen shape of the orthogonal residual in q²-space, the bin fractions after detector smearing, the absence of a high-q² tail, tauonic control, and the directional agreement measured by η_res. The main numerical benchmark values are: m_X = 2.10 (+0.20 / −0.10) GeV q_X² = 4.41 (+0.88 / −0.41) GeV² B(B⁺ → K⁺X)·P_X,inv = 9.2 (+1.8 / −3.4) × 10⁻⁶ For ITA reconstruction with approximate resolution σ_q² = 1.0 GeV², the predicted bin fractions are: r_ITA = (0.3409, 0.6589, 1.65 × 10⁻⁴). BKT-40 does not claim confirmation of the full LOM–GTSFC–USC–GTCW framework. Its role is to formulate a falsifiable benchmark. If future or independently analyzed Belle II data do not reproduce the location and shape of the residual in q², the minimal benchmark is rejected. If the shape is reproduced, the result may indicate a significant structure beyond a simple scalar fit of the Standard Model, but it does not automatically validate the global USC theory. BKT-40 is directly connected to BKT-39. BKT-39 defines the formal geometry of null anchors, projections, and constraints, whereas BKT-40 applies that apparatus to a concrete numerical hypothesis in the rare-B-decay sector.