Dark Matter Dilution Mechanism through the Lens of Large Scale Structure

Abstract

Entropy production is a necessary ingredient for addressing the over-population of thermal relics. It is widely employed in particle physics models for explaining the origin of dark matter. A long-lived particle that decays to the known particles, while dominating the universe, plays the role of the dilutor. We point out the impact of its partial decay to dark matter on the primordial matter power spectrum. For the first time, we derive a stringent limit on the branching ratio of the dilutor to dark matter from large scale structure observation using the SDSS data. This offers a novel tool for testing models with a dark matter dilution mechanism. We apply it to the left-right symmetric model and show that it firmly excludes a large portion of parameter space for right-handed neutrino warm dark matter.

6 pages, 4 figures. v2: added supplement material. Accepted for publication in Physical Review Letters

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Cited by in corpus (5)

• Can Neutrino Self-interactions Save Sterile Neutrino Dark Matter?
• Left-Right Symmetry at FCC-hh
• Long-lived heavy neutral leptons at lepton colliders as a probe of left-right symmetric models
• Decaying scalar dark matter in the minimal left-right symmetric model
• Imprints of an early matter-dominated era arising from dark matter dilution mechanism on cosmic string dynamics and gravitational wave signatures