BBN and the CMB constrain neutrino coupled light WIMPs

By K. Nollett, G. Steigman. 2014

132 citations recorded by the source corpus.

(abridged) In the presence of a light WIMP (mass m_chi 35 MeV, equivalent to no light WIMP at all. All masses below 4--9 MeV (depending on spin) are excluded. Without any light WIMP, BBN alone prefers Delta N_nu = 0.50 +- 0.23, favoring neither Delta N_nu = 0, nor a fully thermalized sterile neutrino (Delta N_nu = 1). This result is consistent with the CMB constraint, N_eff = 3.30 +- 0.27, limiting "new physics" between BBN and recombination. Combining BBN and CMB data gives Delta N_nu = 0.35 +- 0.16 and N_eff = 3.40 +- 0.16; while BBN and the CMB combined require Delta N_nu > 0 at ~98% confidence, they disfavor Delta N_nu > 1 at > 99% confidence. Allowing a neutrino-coupled light WIMP extends the allowed range slightly downward for Delta N_nu and slightly upward for N_eff simultaneously, leaving best-fit values unchanged.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/4a8c3dada02bb2d8a8d196b0c3140b819e42270a

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In Astronomy and Astrophysics

1. Miguel Escudero
2. Tongyan Lin
3. M. Fairbairn
4. J.B.G. Alvey
5. N. Sabti
6. D. Blas
7. I. Mocioiu
8. P. Schuster

In Nuclear and High Energy Physics

1. Miguel Escudero
2. G. Krnjaic
3. Tongyan Lin
4. M. Fairbairn
5. J.B.G. Alvey
6. N. Sabti
7. D. Blas
8. T. Han

Citations in the corpus

• Neutrino non-standard interactions: A status report (2019, background): “CMB observations disfavor light DM, and a conservative lower bound on the DM mass is shown in grey on the left side of each panel [267–269].”
• Neutrino decoupling beyond the Standard Model: CMB constraints on the Dark Matter mass with a fast and precise Neff evaluation (2018, background): “Finally, we note that generically a change on Neff is also accompanied by a change on the primordial Helium abundance [18, 21, 22] (Yp), and the CMB is sensitive to both [1, 2].”
• Dark matter, millicharges, axion and scalar particles, gauge bosons, and other new physics with LDMX (2018, background): “[125] K.”
• Refined bounds on MeV-scale thermal dark sectors from BBN and the CMB (2019, methodology): “Refs [97] and [98] used a modified version of the Kawano code [162, 163].”
• Dark matter models and direct detection (2019, methodology): “[78, 79, 80] used measurements of abundances and the baryon density to set lower bounds on the DM mass mχ & 1−10 MeV, with the specific number depending on the number of degrees of freedom of the candidate.”