UCLA Dark Matter 2025

A Fresh Look at Neutrino Self-Interactions With the Lyman-α Forest

Not scheduled

20m

UCLA Physics and Astronomy Building 1-425

Poster

Speaker

Adam He

Description

We present the first analysis of neutrino self-interactions with two new, state-of-the-art Lyman-$\alpha$ likelihoods: an EFT-based likelihood developed from the Sherwood simulation suite, and a compressed likelihood developed from the PRIYA simulation suite. We find that the inclusion of either Lyman-$\alpha$ dataset penalizes the delay in neutrino free-streaming, previously found to be highly preferred by a combination of CMB and LSS data. We also jointly analyze Planck and DESI BAO data, which does not alter the preference for $\mathrm{\Lambda }$CDM over neutrino-neutrino scattering found in a Planck--only analysis. Our results highlight the importance of modeling the Lyman-$\alpha$ forest accurately.