Particle decays during the cosmic dark ages

By Xuelei Chen, M. Kamionkowski. 2003

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We consider particle decays during the cosmic dark ages with two aims: (1) to explain the high optical depth reported by the Wilkinson Microwave Anisotropy Probe (WMAP), and (2) to provide new constraints to the parameter space for decaying particles. We delineate the decay channels in which most of the decay energy ionizes and heats the intergalactic medium gas [and thus affects the cosmic microwave background (CMB)], and those in which most of the energy is carried away—e.g. photons with energies 100 keV<~E<~1 TeV—and thus appears as a contribution to diffuse x-ray and gamma-ray backgrounds. The new constraints to the decay-particle parameters from the CMB power spectrum thus complement those from the cosmic x-ray and gamma-ray backgrounds. Although decaying particles can indeed produce an optical depth consistent with that reported by WMAP, in so doing they produce new fluctuations in the CMB temperature and polarization power spectra. For decay lifetimes less than the age of the Universe, the induced power spectra generally violate current constraints, while the power spectra are usually consistent if the lifetime is longer than the age of the Universe.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b792523244efe28761d236503064858af6e4f603

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Citations in the corpus

Extended gamma-ray emission from Coy Dark Matter (2014, background): “Secondly, the cosmic microwave background (CMB) provides constraints from the energy deposition arising from dark matter annihilation [106].”
The First Cosmic Structures and Their Effects (2004, background): “Chen & Kamionkowski (2004) have studied these particles, deriving the channels in which most of the decay energy ionizes and heats the IGM gas and those in which most of the energy is instead carried away (e.g. photons with energies 100 keV E 1 TeV).”
21 cm cosmology in the 21st century (2011, background): “Perhaps the most commonly considered source of heating in the dark ages is that of dark matter annihilation [79, 80, 81, 82, 83].”
The effects of QCD equation of state on the relic density of WIMP dark matter (2015, background): “The strongest limits on 〈σv〉 originate from the fact that WIMP annihilation heats up the plasma in the “recombination” epoch when neutral atoms first formed [61, 62], thereby delaying the decoupling of the CMB photons and distorting the pattern of CMB anisotropies.”
Observational Constraints on Cosmic Reionization (2006, neutral): “J. Lett., 606, L25-28 Bouwens et al. 2004Bouwens, R.”
Towards a complete treatment of the cosmological recombination problem (2010, background): “…and allows us to provide extensio, e.g., to account for the effect ofdark matter annihilation, energy injection by decaying particles(e.g. see Chen & Kamionkowski 2004; Padmanabhan & Finkbeiner 2005; Chluba 2010), or thevariation of fundamental constants(Kaplinghat et al. 1999; Galli et al.…”
Cosmological constraints on exotic injection of electromagnetic energy (2016, background): “1 we plot the functions f(z) for decays into electrons and photons, for several DM 4The subscript i stands in practice for either e± or γ’s, the only particles able to efficiently interact with the IGM [21].”