Dark matter of weakly interacting massive particles and the QCD equation of state

Hindmarsh, Mark and Philipsen, Owe (2005) Dark matter of weakly interacting massive particles and the QCD equation of state. Physical Review D, 71 (8). 087302. ISSN 1550-7998

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Abstract

Weakly Interacting Massive Particles (WIMPs) of mass m freeze-out at a temperature Tf~=m/25, i.e. in the range 400 MeV40 GeV for a particle in the typical mass range 101000 GeV. The WIMP relic density, which depends on the effective number of relativistic degrees of freedom at Tf, may be measured to better than 1% by Planck, warranting comparable theoretical precision. Recent theoretical and experimental advances in the understanding of high-temperature QCD show that the quark gluon plasma departs significantly from ideal behavior up to temperatures of several GeV, necessitating an improvement of the cosmological equation of state over those currently used. We discuss how this increases the relic density by approximately 1.53.5% in benchmark mSUGRA models, with an uncertainty in the QCD corrections of 0.51%. We point out what further work is required to achieve a theoretical accuracy comparable with the expected observational precision, and speculate that the effective number of degrees of freedom at Tf may become measurable in the foreseeable future.

Item Type: Article
Additional Information: Collaboration co-leader, concerned with cosmological implications. We show that recent advances in the understanding of the equation of state of strongly interacting particles have detectable effects for future precision determinations of the abundance of weakly interacting dark matter.
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Depositing User: Mark Hindmarsh
Date Deposited: 06 Feb 2012 19:54
Last Modified: 07 Mar 2017 09:24
URI: http://sro.sussex.ac.uk/id/eprint/22861

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