The Two-Population Structure of L-Function Zero Spacings: dim=1 to GUE, dim>=2 to Poisson with 6% Outliers

Empirical evidence for a dimension-dependent transition in L-function zero spacing statistics, analyzing 63,844 weight-2 newforms from the LMFDB database. Key findings: (1) Two-population structure: dim=1 forms exhibit GUE statistics (Brody beta=1.88), dim>=2 forms exhibit near-Poisson statistics (beta=0.24). (2) Continuous transition: beta decreases monotonically with dimension. (3) GUE outliers: 6% of dim>=2 forms retain GUE statistics, characterized as low-dimension, small-level forms. (4) Predictability: Spectral rigidity predictable from scalar metadata alone (R-squared>0.93), Hecke traces contribute negligible signal (Delta R-squared<0.02).