Addendum to: Update on neutrino mixing in the early Universe

Abstract

In the light of the recent WMAP results we update the constraints on a class of non standard BBN models with a simultaneous combination of non standard neutrino distributions and extra effective number of neutrinos in the expansion rate. These models can be described in terms of the two parameters Delta N_nu^tot, constrained by the primordial Helium abundance Y_p measurement, and Delta N_nu^rho, constrained by a combination of CMB and primordial Deuterium data. Small deviations from standard BBN are suggested. Different non standard scenarios can be distinguished by a measurement of the difference Delta N_nu^f_nu=Delta N_nu^tot-Delta N_nu^rho. From the current data we estimate Delta N_nu^f_nu simeq -1.4^{+0.9}_{-1.4}, mildly disfavouring solutions with a low expansion rate, characterized by Delta N_nu^f_nu=0 and negative Delta N_nu^rho. Active-sterile neutrino mixing could be a viable explanation only for high values of Y_p gtrsim 0.24. The existence of large positive neutrino chemical potentials xi_i sim 0.05, implying Delta N_nu^rho simeq 0, would be a possible explanation of the data within the analyzed class of non standard BBN models. Interestingly it would also provide a way to evade the cosmological bounds for `class A 3+1' four neutrino mixing models. A scenario with a decaying sterile neutrino is also considered.

addendum to hep-ph/0108182 after WMAP results; 10 pages; v3: to appear on PRD, added discussion on decaying nu_st

References in corpus (2)

• Ruling out four-neutrino oscillation interpretations of the LSND anomaly?
• Global analysis of neutrino oscillation data in four-neutrino schemes

Cited by in corpus (31)

• Cosmological parameters from SDSS and WMAP
• Sterile neutrino oscillations after first MiniBooNE results
• Cosmology seeking friendship with sterile neutrinos
• Neutrino masses and the number of neutrino species from WMAP and 2dFGRS
• A combined analysis of short-baseline neutrino experiments in the (3+1) and (3+2) sterile neutrino oscillation hypotheses
• Probing oscillations into sterile neutrinos with cosmology, astrophysics and experiments
• Mirror dark matter and large scale structure
• Sterile-active neutrino oscillations and shortcuts in the extra dimension
• Hiding relativistic degrees of freedom in the early universe
• Cosmological Lepton Asymmetry, Primordial Nucleosynthesis, and Sterile Neutrinos
• Simultaneous Flavor Transformation of Neutrinos and Antineutrinos with Dominant Potentials from Neutrino-Neutrino Forward Scattering
• Sterile neutrinos, lepton asymmetries, primordial elements: how much of each?
• Light sterile neutrino production in the early universe with dynamical neutrino asymmetries
• Constraining the helium abundance with CMB
• Dark Radiation or Warm Dark Matter from long lived particle decays in the light of Planck
• Late Time Neutrino Masses, the LSND Experiment and the Cosmic Microwave Background
• Light Element Signatures of Sterile Neutrinos and Cosmological Lepton Numbers
• Naturally Light Sterile Neutrinos from Theory of R-parity
• Are Light Sterile Neutrinos Preferred or Disfavored by Cosmology?
• LSND versus MiniBooNE: Sterile neutrinos with energy dependent masses and mixing?
• Cosmological neutrino bounds for non-cosmologists
• Chiral Gauge Models for Light Sterile Neutrinos
• Joint constraints on the lepton asymmetry of the Universe and neutrino mass from the Wilkinson Microwave Anisotropy Probe
• Particle physics implications of the WMAP neutrino mass bound
• Relaxed constraints on neutrino oscillation parameters
• Neutrinos in a Sterile Throat
• Neutrino Oscillations in Deconstructed Dimensions
• More General BBN Constraints on Neutrino Oscillations Parameters - Relaxed or Strengthened
• Light Sterile Neutrinos in the Supersymmetric U(1)' Models and Axion Models
• Chaos, Determinacy and Fractals in Active-Sterile Neutrino Oscillations in the Early Universe
• The effect of primordial fluctuations on neutrino oscillations