Systematic comparison of the official RIPL-3 HFB+combinatorial level densities with evaporation data for 60,61Zn: isolation of an N ≈ Z-specific excess above a shared baseline

Email contact : multiversou@gmail.com This work presents a zero-free-parameter comparison between the official RIPL-3 renormalization of the HFB+combinatorial level densities (Goriely, Hilaire, Koning) and neutron-evaporation data for the N ≈ Z nuclei ⁶⁰Zn and ⁶¹Zn, with the stable nucleus ⁶⁴Zn used as an independent control. The analysis independently tests the level-density suppression anomaly reported by Soltesz et al. (PRC 103, 015802, 2021) in the E_ex ≈ 3–9 MeV window, previously modelled by Roy et al. (PLB 859, 139101, 2024) via a Wigner damping term in the BSFG. Methodology Direct application of Eq. (1) from the RIPL-3 Handbook, with parameters p and c as distributed in the z030.core files, without any adjustment. Resolution of the column-assignment ambiguity in z030.core (unlabeled column → p, not c), verified numerically against the data and consistent with the rule c = 0 when no D₀ is measured. For both N ≈ Z isotopes the renormalization is therefore constrained solely by low-lying discrete levels. Use of RHOOBS (level density, summed over both parities) rather than RHOTOT (state density), verified numerically. Comparison with the 40 data points of Soltesz (⁶⁰Zn) and the 14 numerical values of Roy (⁶¹Zn) using an asymmetric logarithmic χ² statistic. Main Results Systematic official mismatch: the renormalized RIPL-3 density overpredicts the data from the onset of the Soltesz plateau (E_ex ≈ 5 MeV) upward, reaching a factor of 6–7 at E_ex ≈ 9 MeV (χ²/dof = 3.30 for ⁶⁰Zn, 6.90 for ⁶¹Zn). Shared baseline from the ⁶⁴Zn control: applying the identical procedure to ⁶⁴Zn (CANDL data / Ramirez et al. PRC 88, 064324) isolates a generic, isotope-independent mismatch of order ~2 with mild energy dependence; a linear regression of ln(ρ_model/ρ_data) on E_ex yields a residual scatter σ ≈ 0.188. Residual N ≈ Z-specific excess: after subtracting the ⁶⁴Zn baseline, ⁶⁰Zn shows a highly significant excess, coincident within ~0.5 MeV with the onset of the experimental plateau: χ²/dof ≈ 30.7 for E_ex ≥ 5.5 MeV, mean factor ≈ 2.84× (~5.5σ), positive at all 26 points in the window. Under a more conservative uncertainty budget (experimental uncertainties added in quadrature) the significance drops to ~1.6σ on average but remains positive at all points. Two-parameter phenomenological refit: a direct fit of (p, c) to the same data removes the systematic trend and gives χ²/dof = 0.071 (⁶⁰Zn) and 0.105 (⁶¹Zn), lower than the BSFG+Wigner model at equal or greater number of parameters. The fitted c values are negative for both isotopes (damping, not enhancement). Discussion and Implications For RIPL-3 / Hauser-Feshbach users: the generic baseline mismatch documented on ⁶⁴Zn indicates that the official renormalization should not be trusted at the factor-of-a-few level in the E_ex ≈ 3–9 MeV window for any nucleus, irrespective of N − Z. For N ≈ Z physics: above the generic baseline, an additional excess of comparable magnitude remains, which any future microscopic explanation must reproduce. Isoscalar np pairing (T = 0) hypothesis: absent from the underlying BSk14 functional, it is a structurally plausible but energetically unconfirmed candidate; existing studies of the Wigner energy in masses do not clearly support its energetic role. The authors do not adopt it as the central narrative, calling instead for a direct calculation of ρ(E_ex) with and without the isoscalar channel for ⁶⁰Zn.