Probing lepton asymmetry with 21 cm fluctuations

Journal Article · Mon Sep 01 00:00:00 EDT 2014 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2014/09/014· OSTI ID:22375897

Kohri, Kazunori; Oyama, Yoshihiko ^[1]; Sekiguchi, Toyokazu ^[2]; Takahashi, Tomo ^[3]

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1. The Graduate University for Advanced Studies (Sokendai), 1-1 Oho, Tsukuba 305-0801 (Japan)
2. Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602 (Japan)
3. Department of Physics, Saga University, Saga 840-8502 (Japan)

We investigate the issue of how accurately we can constrain the lepton number asymmetry ξ{sub ν}=μ{sub ν}/T{sub ν} in the Universe by using future observations of 21 cm line fluctuations and cosmic microwave background (CMB). We find that combinations of the 21 cm line and the CMB observations can constrain the lepton asymmetry better than big-bang nucleosynthesis (BBN). Additionally, we also discuss constraints on ξ{sub ν} in the presence of some extra radiation, and show that the 21 cm line observations can substantially improve the constraints obtained by CMB alone, and allow us to distinguish the effects of the lepton asymmetry from the ones of extra radiation.

• OSTI ID: 22375897
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2014, Issue 09; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASYMMETRY
FLUCTUATIONS
LEPTON NUMBER
LEPTONS
NUCLEOSYNTHESIS
PROBES
RELICT RADIATION
UNIVERSE