Speaker
Description
In this talk I will introduce the key cosmological datasets — the cosmic
microwave background and galaxy surveys — and explain how they serve as particle
detectors for the lightest particles in nature. I will describe the vast landscape of
dark matter candidates, spanning many orders of magnitude in mass, and show how
cosmological observables can distinguish among them. A central theme of my work is
the growth-induced scale-dependent bias (GISDB): the insight that purely gravitational
effects of particles modify not only the matter distribution but also the relationship
between halos and the underlying matter field. This effect, arising from the physics of
spherical collapse and the peak-background split, provides an independent channel of
information beyond the matter power spectrum alone.
I will discuss the ability of surveys to detect or rule out broad classes of light thermal
relics, and demonstrate that even percent-level abundances of ultra-light axion dark
matter (10−33 ≤ mϕ/eV ≤ 10−22) produce significant signatures in the halo bias. I
will also describe my recent work on model-independent relic constraints, showing what
existing Planck CMB data can tell us about any monomodal light relic.
| Other topic / keywords: | axions |
|---|