Constraining the Lyman-Alpha Forest without Dark Matter: A Zero-Degree-of-Freedom Baseline

We present a Lyman-Alpha Forest (Lyα) validation testing whether the standard observablescan be explained without any form of Dark matter. Using a cosmological model with zero degrees offreedom (ZERO–DOF) and fixed baryonic content only, we evaluate the compatibility of Lyαobservables with a no-matter scenario. We include analyses of the 1D flux power spectrumP1D(k), flux probability distribution functions (PDFs), and large-scale structure distortions(BAO/RSD). We compare performance against ΛCDM and alternate models, compute metricsper validation block, and highlight how nuisance parameters can mimic cosmological signals.Our results show that within Lyα-only statistics, the no-matter hypothesis remains compatiblewhen using internal refits only, with implications for model selection via Occam’s razor.