The gallium anomaly, a 20% deficit in the measured ν_e captures on ⁷¹Ga, remains unexplained. A recent work [Phys. Rev. Lett. 137, 131805 (2026), arXiv:2512.20560] had proposed solving it by assuming the breakdown of the factorization of lepton and nuclear wavefunctions underlying the cross-section prediction, combined with ad hoc Gamow-Teller nuclear transition densities.

A new analysis now tests that proposal with transition densities calculated within the nuclear shell model (NSM), normalized to the ⁷¹Ge electron-capture half-life and convolved with Dirac-Hartree-Fock-Slater electron wavefunctions. The authors explore several NSM interactions, bare and effective Gamow-Teller operators, and the impact of the valence space. In all cases they obtain remarkably consistent NSM transition densities.

The central result is that factorized and nonfactorized cross sections agree with each other and remain 20% higher than the measured value. In addition, using NSM single-nucleon transition densities as an ansatz, they find that solving the anomaly would require fine-tuned densities, with percent-level cancellations and an overall scale orders of magnitude larger than the calculated NSM ones.

The authors conclude that the gallium anomaly is not solved when using realistic nuclear transition densities, leaving open the search for an alternative explanation, whether in nuclear physics or in neutrino physics.