Relic neutrino decoupling including flavour oscillations
read the original abstract
In the early universe, neutrinos are slightly coupled when electron-positron pairs annihilate transferring their entropy to photons. This process originates non-thermal distortions on the neutrino spectra which depend on neutrino flavour, larger for nu_e than for nu_mu or nu_tau. We study the effect of three-neutrino flavour oscillations on the process of neutrino decoupling by solving the momentum-dependent kinetic equations for the neutrino spectra. We find that oscillations do not essentially modify the total change in the neutrino energy density, giving N_eff=3.046 in terms of the effective number of neutrinos, while the small effect over the production of primordial 4He is increased by O(20%), up to 2.1 x 10^{-4}. These results are stable within the presently favoured region of neutrino mixing parameters.
This paper has not been read by Pith yet.
Forward citations
Cited by 12 Pith papers
-
Gravitational Waves from Black Hole Reheating: The Scalar-Induced Component
Accounting for the minimal mass spread of primordial black holes from gravitational collapse suppresses the Poltergeist GW background to the level of generic scalar-induced signals and reopens ultra-light PBH parameter space.
-
Cosmological analysis of the DESI DR1 Lyman alpha 1D power spectrum
DESI DR1 Lyman-alpha data yields Δ²★=0.379±0.032 and n★=-2.309±0.019 at k★=0.009 km⁻¹s and z=3, sharpening N_eff, α_s, and β_s constraints by factors of 1.18-1.90 when combined with other probes.
-
Consistent $N_{\rm eff}$ fitting in big bang nucleosynthesis analysis
Conventional BBN fitting for negative Delta N_eff is unphysical; a consistent treatment via entropy dilution after neutrino decoupling yields significantly different bounds.
-
DESI 2024 VII: Cosmological Constraints from the Full-Shape Modeling of Clustering Measurements
DESI DR1 full-shape clustering yields Ω_m = 0.2962 ± 0.0095 and σ_8 = 0.842 ± 0.034 in flat ΛCDM, tightening to H_0 = 68.40 ± 0.27 km/s/Mpc with CMB and DESY3, while favoring w_0 > -1, w_a < 0 and limiting neutrino ma...
-
Bipartite Solution to the Lithium Problem
A sequential majoron-to-neutrinos decay followed by axion-like particle-to-photons decay can lower primordial lithium without exceeding deuterium limits.
-
Cosmological Probes of Lepton Parity Freeze-in Dark Matter: $\Delta N_{\rm eff}$ & Gravitational Waves
Lepton parity stabilizes a Majorana fermion as freeze-in dark matter produced via right-handed neutrino or Higgs decays, yielding detectable gravitational waves or ΔN_eff depending on scalar couplings.
-
Planck 2018 results. VI. Cosmological parameters
Final Planck CMB data confirms the flat 6-parameter ΛCDM model with Ω_c h² = 0.120 ± 0.001, Ω_b h² = 0.0224 ± 0.0001, n_s = 0.965 ± 0.004, τ = 0.054 ± 0.007, H_0 = 67.4 ± 0.5 km/s/Mpc, and no strong evidence for extensions.
-
CMB signatures of gravity-mediated dark radiation in $\mathbf{\Delta N_{\rm eff}}$
Gravity-mediated production of scalar and vector dark radiation yields Planck 2018 constraints on reheating temperature T_RH and background equation of state w_Φ, with comparisons to right-handed neutrinos, ALPs, and ...
-
Probing Dark Sector Particles Coupling to Neutrinos with Double Beta Decay
Double beta decay experiments can constrain couplings of sub-MeV Majoron-like scalars to neutrinos at |a_ν| ≈ 2×10^{-6} through on- and off-shell production effects on the electron spectrum.
-
The DESI Experiment Part I: Science,Targeting, and Survey Design
DESI will target luminous red galaxies to z=1, emission-line galaxies to z=1.7, quasars for tracers and Ly-alpha forest at 2.1<z<3.5, plus a bright galaxy survey, to obtain more than 30 million redshifts for BAO and m...
-
Axions as Dark Matter, Dark Energy, and Dark Radiation
A mini-review of axion phenomenology showing how light bosons can account for dark matter, drive cosmic acceleration, or contribute to relativistic backgrounds in the early and late Universe.
-
In the Realm of the Hubble tension $-$ a Review of Solutions
A review summarizing the Hubble constant tension and proposed solutions from new physics that restore agreement between Planck CMB data and local H0 measurements within 1-2 sigma.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.