Impacts of dark matter particle annihilation on recombination and the anisotropies of the cosmic microwave background

Journal Article · Wed Nov 15 04:00:00 EST 2006 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.74.103519· OSTI ID:20864106

Le, Zhang ^[1]; Xuelei, Chen ^[1]; Yian, Lei ^[2]; Zongguo, Si ^[3]

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1. National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China)
2. Department of Physics, Peking University, Beijing, 100871 (China)
3. Department of Physics, Shandong University, Jinan, 250100 (China)

The recombination history of the Universe provides a useful tool for constraining the annihilation of dark matter particles. Even a small fraction of dark matter particles annihilated during the cosmic dark age can provide sufficient energy to affect the ionization state of the baryonic gas. Although this effect is too small for neutralinos, lighter dark matter particle candidates, e.g. with mass of 1-100 MeV, which was proposed recently to explain the observed excess of positrons in the galactic center, may generate observable differences in the cosmic microwave background (CMB) temperature and polarization anisotropies. The annihilations at the era of recombination affects mainly the CMB anisotropy at small angular scales (large l), and is distinctively different from the effect of early reionization. We perform a multiparameter analysis of the CMB data, including both the Wilkinson Microwave Anisotropy Probe (WMAP) first year and three year data, and the ACBAR, Boomerang, CBI, and VSA data. Assuming that the observed excess of e{sup +}e{sup -} pairs in the galactic center region is produced by dark matter annihilation, and that a sizable fraction of the energy produced in the annihilation is deposited in the baryonic gas during recombination, we obtain a 95% dark matter mass limit of M<8 MeV with the current data set.

• OSTI ID: 20864106
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 10 Vol. 74; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANISOTROPY
ANNIHILATION
BARYONS
COSMOLOGY
ELECTRONS
IONIZATION
MEV RANGE
MULTI-PARAMETER ANALYSIS
NONLUMINOUS MATTER
POLARIZATION
POSITRONS
RECOMBINATION
RELICT RADIATION
REST MASS
UNIVERSE