Hemispheric Asymmetry in Energy and Signalness of IceCube GOLD Events: An Exploratory Analysis with BRONZE-Class Control Verification

We report two spatial patterns in the IceCube GOLD alert dataset (N=62, 2019-2026): (1) a statistically significant energy asymmetry between southern and northern sky events (median 349 TeV vs. 202.5 TeV, Mann-Whitney p=0.0189), and (2) an elevated signalness trend in the Leo core zone (RA=120-150 deg), with Leo mean signalness 0.721 vs. 0.558 (p=0.112; not statistically significant). A pre-specified BRONZE-class control analysis (N=118) found neither pattern in BRONZE data (p=0.516 and p=0.729, respectively). This contrast is not readily explained by IceCube directional sensitivity alone, though differences in selection thresholds between GOLD and BRONZE cannot be excluded. Whether the observed patterns reflect distinct astrophysical physics or residual selection systematics cannot be determined from this exploratory analysis. Independent pre-registered verification is required. This manuscript (v2) incorporates a BRONZE-class control pre-specified before execution, and three interpretation corrections in response to adversarial AI review.