Narrowing the window for millicharged particles by CMB anisotropy

By S. Dubovsky, D. Gorbunov, G. Rubtsov. 2003

143 citations recorded by the source corpus.

We calculate the cosmic microwave background (CMB) anisotropy spectrum in models with millicharged particles of electric charge q∼10−6−10−1 in units of electron charge. We find that a large region of the parameter space for the millicharged particles exists where their effect on the CMB spectrum is similar to the effect of baryons. Using WMAP data on the CMB anisotropy and assuming the Big Bang nucleosynthesis value for the baryon abundance, we find that only a small fraction of cold dark matter, Ωmcp<0.007 (at 95% CL), may consist of millicharged particles with the parameters (charge and mass) from this region. This bound significantly narrows the allowed range of the parameters of millicharged particles. In models without paraphotons, millicharged particles are now excluded as a dark matter candidate. We also speculate that recent observation of 511-keV γ rays from the Galactic bulge may be an indication that a (small) fraction of cold dark matter is comprised of millicharged particles.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b612f0ecebded312f264d994d5a98841d5b72d62

How researchers see this paper

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In Astronomy and Astrophysics

1. J. Redondo
2. A. Ringwald
3. H. Vogel
4. J. Jaeckel
5. V. Khoze
6. S. Abel
7. M. Goodsell
8. Igor G. Irastorza

In Nuclear and High Energy Physics

1. A. Ringwald
2. J. Redondo
3. H. Vogel
4. J. Jaeckel
5. V. Khoze
6. S. Abel
7. M. Goodsell
8. Igor G. Irastorza

Citations in the corpus

• Dark radiation constraints on minicharged particles in models with a hidden photon (2013, methodology): “At the CMB epoch this is defined through ρR = π2 30 [ gγ + 2 7 8 ( 4 11 )4/3 Neff ] T 4γ , (3.2) where gγ = 2 are the photon’s degrees of freedom.”
• Kinetic Mixing of the Photon with Hidden U(1)s in String Phenomenology (2008, background): “[42]), due to the apparent successfullness of standard big bang nucleosynthesis (BBN) [43], and due to the observational requirement that the contribution of MCPs to the energy density should not overclose the universe, Ω = ρ/ρcrit < 1 [44].”
• Direct detection of strongly interacting sub-GeV dark matter via electron recoils (2019, unknown): “[61–67, 69, 70]).”