Speaker
Description
We demonstrate that multi-component scalar ensembles in the early universe can experience a variety of surprising phenomena when subject to a cosmological mass-generating phase transition. These include severe suppressions to their late-time cosmological (relic) abundance, parametrically resonant enhancements, re-distribution of energy density across the ensemble, and a ``re-overdamping'' effect which causes the total energy density to behave in ways that differ from those exhibited by pure dark matter or vacuum energy. Furthermore, in the case of scalar KK models, we find that the tower of KK states becomes self-limiting, i.e. the abundance of higher-mass components is hugely suppressed so that the tower becomes effectively finite. Additionally, we find that modifications in both the total abundance and its distribution varies substantially throughout the model parameter space. These results could have significant implications for cosmological moduli, axion-like particles, or any models with scalar KK towers that undergo mass-generating phase transitions.
