Fundamental physics with the Lyman-alpha forest: constraints on the growth of structure and neutrino masses from SDSS with effective field theory

Abstract

We present an effective field theory (EFT) approach to extract fundamental cosmological parameters from the Lyman-alpha forest flux fluctuations as an alternative to the standard simulation-based techniques. As a first application, we re-analyze the publicly available one-dimensional Lyman-alpha flux power spectrum data from the Sloan Digital Sky Survey. Our analysis relies on informative priors on EFT parameters which we extract from a combination of public hydrodynamic simulation and emulator data. Assuming the concordance cosmological model, our one-parameter analysis yields a $2\%$ measurement of the late time mass fluctuation amplitude $\sigma_8 = 0.841\pm 0.017$, or equivalently, the structure growth parameter $S_8 = 0.852\pm 0.017$, consistent with the standard cosmology. This result is obtained assuming that non-linear EFT parameters are cosmology-independent functions of the linear bias parameter. When this assumption is loosened, the limit degrades by a factor of 3, suggesting that informative priors are necessary for competitive constraints. Combining our EFT likelihood with Planck + baryon acoustic oscillation data, we find a new constraint on the total neutrino mass, $\sum m_\nu<$ 0.08 eV (at 95\% CL). Our study defines priorities for the development of EFT methods and sets the benchmark for cosmological analyses of the Lyman-alpha forest data from the Dark Energy Spectroscopic Instrument.