Constraining the universal lepton asymmetry

@article{Simha2008ConstrainingTU,
  title={Constraining the universal lepton asymmetry},
  author={Vimal Simha and Gary Steigman},
  journal={Journal of Cosmology and Astroparticle Physics},
  year={2008},
  volume={2008},
  pages={011}
}
  • V. Simha, G. Steigman
  • Published 1 June 2008
  • Physics
  • Journal of Cosmology and Astroparticle Physics
The relic cosmic background neutrinos accompanying the cosmic microwave background (CMB) photons may hide a universal lepton asymmetry orders of magnitude larger than the universal baryon asymmetry. At present, the only direct way to probe such an asymmetry is through its effect on the abundances of the light elements produced during primordial nucleosynthesis. The relic light element abundances also depend on the baryon asymmetry, parameterized by the baryon density parameter () and on the… 

Constraints on lepton asymmetry from nucleosynthesis in a linearly coasting cosmology

We study the effect of neutrino degeneracy on primordial nucleosynthesis in a universe in which the cosmological scale factor evolves linearly with time. The degeneracy parameter of electron type

Primordial Lepton Asymmetries in the Precision Cosmology Era: Current Status and Future Sensitivities from BBN and the CMB

Using a new sample of extremely metal poor systems, the EMPRESS survey has recently reported a primordial helium abundance that is 3 σ smaller than the prediction from the Standard BBN scenario. This

Constraining the cosmic radiation density due to lepton number with BBN

We discuss the bounds on the cosmological lepton number from Big Bang Nucleosynthesis (BBN), in light of recent evidences for a non-zero value of the neutrino mixing angle θ13 (sin2 θ13 ≳ 0.005 at

Constraining the cosmic radiation density due to lepton number with Big Bang Nucleosynthesis

The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos Neff. This quantity, in

Cosmological evidence for leptonic asymmetry after Planck

Recently, the PLANCK satellite found a larger and most precise value of the matter energy density, that impacts on the present values of other cosmological parameters such as the Hubble constant H0,

Subdominant Dark Matter sterile neutrino resonant production in the light of PLANCK

Few independent detections of a weak X-ray line at an energy of ∼ 3.5 keV seen toward a number of astrophysical sites have been reported. If this signal will be confirmed to be the signature of

Thermalisation of light sterile neutrinos in the early universe

Recent cosmological data favour additional relativistic degrees of freedom beyond the three active neutrinos and photons, often referred to as ``dark'' radiation. Light sterile neutrinos is one of

CP violation in bilinear R-parity violation and its consequences for the early universe

Supersymmetric models with bilinear R-parity violation (BRpV) provide a framework for neutrino masses and mixing angles to explain neutrino oscillation data. We consider CP violation within the new
...

References

SHOWING 1-10 OF 67 REFERENCES

Constraining the early-Universe baryon density and expansion rate

We explore the constraints on those extensions to the standard models of cosmology and particle physics which modify the early-Universe, radiation dominated, expansion rate (parameterized by the

The standard and degenerate primordial nucleosynthesis versus recent experimental data

We report the results on Big Bang Nucleosynthesis (BBN) based on an updated code, with accuracy of the order of 0.1 % on 4He abundance, compared with the predictions of other recent similar analysis.

Lepton asymmetry and primordial nucleosynthesis in the era of precision cosmology

We calculate and display the primordial light-element abundances as a function of a neutrino degeneracy parameter {xi} common to all flavors. It is the only unknown parameter characterizing the

Majorana neutrinos, nucleosynthesis, and the lepton asymmetry of the Universe

The lepton asymmetry Lapprox. =(n/sub ..nu../-n/sub nu-bar/)/n/sub ..gamma../ of the Universe is one of the main uncertainties in the standard hot big-bang cosmological model. Direct limits on L from

BBN for pedestrians

The simplest, ‘standard’ model of Big Bang nucleosynthesis (SBBN) assumes three light neutrinos (Nν = 3) and no significant electron neutrino asymmetry ( asymmetry parameter ξe ≡ μe/kT, where μe is

Signatures of relativistic neutrinos in CMB anisotropy and matter clustering

We present a detailed analytical study of ultrarelativistic neutrinos in cosmological perturbation theory and of the observable signatures of inhomogeneities in the cosmic neutrino background. We

Constraints on non-thermal dark matter from PLANCK lensing extraction

Distortions of CMB (cosmic microwave background) temperature and polarization anisotropy maps caused by gravitational lensing, observable with high angular resolution and sensitivity, can be used to
...