Dark-photon dark matter at 5–46 kHz: a pre-registered in-situ search in seventeen years of Ulysses radio spectra

Preprint and complete analysis record for a pre-registered search for dark-photon dark matter converting resonantly in the solar wind, using 5529 days (1991–2007) of public Ulysses URAP radio spectra. Result: no line is found. The 95% power-constrained upper limits on the kinetic mixing reach 3×10-16 at 22 kHz, and all 56 channels between 5.00 and 46.25 kHz lie in the linear-conversion window. At 28–46 kHz the limits are 36–146 times below the STEREO limit at the same frequency. Between 5 and 28 kHz the only previous constraint was Leo T heating at ε ~ 10-9. Protocol: pre-registration with a logged change history, code frozen by hash before a single unblinding, and robustness rows R1–R13. One validation gate failed twice, and the uncertainty inflation (×1.74) chosen before unblinding is applied throughout. The research was carried out with an AI tool (Claude, Anthropic) under the author's direction; see the declaration in the paper.