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Title: Long-lived light mediator to dark matter and primordial small scale spectrum

We calculate the early universe evolution of perturbations in the dark matter energy density in the context of simple dark sector models containing a GeV scale light mediator. We consider the case that the mediator is long-lived, with lifetime up to a second, and before decaying it temporarily dominates the energy density of the universe. We show that for primordial perturbations that enter the horizon around this period, the interplay between linear growth during matter domination and collisional damping can generically lead to a sharp peak in the spectrum of dark matter density perturbation. Finally, as a result, the population of the smallest DM halos gets enhanced. Possible implications of this scenario are discussed.
Authors:
 [1]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States). Walter Burke Inst. for Theoretical Physics
Publication Date:
Grant/Contract Number:
SC0010255; FG02-92ER40701
Type:
Accepted Manuscript
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2015; Journal Issue: 05; Journal ID: ISSN 1475-7516
Publisher:
Institute of Physics (IOP)
Research Org:
California Inst. of Technology (CalTech), Pasadena, CA (United States)
Sponsoring Org:
USDOE; Gordon and Betty Moore Foundation
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; power spectrum; dark matter theory; particle physics - cosmology connection; cosmological perturbation theory
OSTI Identifier:
1440978

Zhang, Yue. Long-lived light mediator to dark matter and primordial small scale spectrum. United States: N. p., Web. doi:10.1088/1475-7516/2015/05/008.
Zhang, Yue. Long-lived light mediator to dark matter and primordial small scale spectrum. United States. doi:10.1088/1475-7516/2015/05/008.
Zhang, Yue. 2015. "Long-lived light mediator to dark matter and primordial small scale spectrum". United States. doi:10.1088/1475-7516/2015/05/008. https://www.osti.gov/servlets/purl/1440978.
@article{osti_1440978,
title = {Long-lived light mediator to dark matter and primordial small scale spectrum},
author = {Zhang, Yue},
abstractNote = {We calculate the early universe evolution of perturbations in the dark matter energy density in the context of simple dark sector models containing a GeV scale light mediator. We consider the case that the mediator is long-lived, with lifetime up to a second, and before decaying it temporarily dominates the energy density of the universe. We show that for primordial perturbations that enter the horizon around this period, the interplay between linear growth during matter domination and collisional damping can generically lead to a sharp peak in the spectrum of dark matter density perturbation. Finally, as a result, the population of the smallest DM halos gets enhanced. Possible implications of this scenario are discussed.},
doi = {10.1088/1475-7516/2015/05/008},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 05,
volume = 2015,
place = {United States},
year = {2015},
month = {5}
}