Resonant neutrino self-interactions: Insights from the full shape galaxy power spectrum

TL;DR

This study uses the effective field theory of large-scale structure to place the most stringent cosmological constraints to date on resonant neutrino self-interactions, analyzing their effects on matter distribution with galaxy clustering, BBN, and CMB data.

Contribution

It introduces the first application of the effective field theory of large-scale structure to model resonant neutrino self-interactions on mildly nonlinear scales in cosmology.

Findings

FS+Planck data constrains interaction strength to g_ν< 10.8×10^{-14} at 95% confidence.

FS+BBN constrains the 10 eV mediator independently, with g_ν< 7.33×10^{-12}.

Resonant neutrino self-interactions are unlikely to resolve cosmological tensions.

Abstract

This paper investigates resonant neutrino self-interactions in cosmology by employing, for the first time, the effective field theory of large-scale structure to model their impact on the matter distribution up to mildly nonlinear scales. We explore a broad range of mediator masses in two main analyses: one combining BOSS Full Shape (FS) galaxy clustering with Big Bang Nucleosynthesis (BBN), and another combining FS with Planck Cosmic Microwave Background (CMB) data. Our results place the strongest cosmological constraints to date on the resonant self interactions when using FS+Planck data, reaching up to $g_\nu< 10.8 \times 10^{-14}$ at $95\%$ confidence for the 1 eV mediator. Notably, FS+BBN can constrain the interaction for the 10 eV mediator independently of CMB data, yielding $g_\nu < 7.33 \times 10^{-12}$ at $95\%$ confidence. Our results suggest that resonant neutrino self-interactions are unlikely to resolve existing cosmological tensions within the standard $\Lambda$CDM framework.