Neutrinos And Big Bang Nucleosynthesis

Abstract

The early universe provides a unique laboratory for probing the frontiers of particle physics in general and neutrino physics in particular. The primordial abundances of the relic nuclei produced during the first few minutes of the evolution of the Universe depend on the electron neutrinos through the charged-current weak interactions among neutrons and protons (and electrons and positrons and neutrinos), and on all flavors of neutrinos through their contributions to the total energy density which regulates the universal expansion rate. The latter contribution also plays a role in determining the spectrum of the temperature fluctuations imprinted on the Cosmic Background Radiation (CBR) some 400 thousand years later. Using deuterium as a baryometer and helium-4 as a chronometer, the predictions of BBN and the CBR are compared to observations. The successes of, as well as challenges to the standard models of particle physics and cosmology are identified. While systematic uncertainties may be the source of some of the current tensions, it could be that the data are pointing the way to new physics. In particular, BBN and the CBR are used to address the questions of whether or not the relic neutrinos were fully populated in the early universe and, to limit the magnitude of any lepton asymmetry which may be concealed in the neutrinos.

Accepted for publication in the Proceedings of Nobel Symposium 129, "Neutrino Physics"; to appear in Physics Scripta, eds., L Bergstrom, O. Botner, P. Carlson, P. O. Hulth, and T. Ohlsson

References in corpus (8)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• What is the lowest possible reheating temperature?
• The cosmological baryon density from the deuterium to hydrogen ratio towards QSO absorption systems: D/H towards Q1243+3047
• Systematic effects and a new determination of the primordial abundance of 4He and dY/dZ from observations of blue compact galaxies
• Reappraising the Spite Lithium Plateau: Extremely Thin and Marginally Consistent with WMAP
• Effective number of neutrinos and baryon asymmetry from BBN and WMAP
• BBN For Pedestrians
• Hiding relativistic degrees of freedom in the early universe

Cited by in corpus (18)

• A new determination of the primordial He abundance using the HeI 10830A emission line: cosmological implications
• The primordial abundance of 4He: a self-consistent empirical analysis of systematic effects in a large sample of low-metallicity HII regions
• The Tensor-Vector-Scalar theory and its cosmology
• A New Two Higgs Doublet Model
• SBS 0335-052E+W: deep VLT/FORS+UVES spectroscopy of the pair of the lowest-metallicity blue compact dwarf galaxies
• Primordial 4He abundance: a determination based on the largest sample of HII regions with a methodology tested on model HII regions
• TeVeS Cosmology : Covariant formalism for the background evolution and linear perturbation theory
• Perturbative Non-Equilibrium Thermal Field Theory
• Constraints on Tsallis Cosmology from Big Bang Nucleosynthesis and the Relic Abundance of Cold Dark Matter Particles
• Helium and Deuterium Abundances as a Test for the Time Variation of the Fine Structure Constant and the Higgs Vacuum Expectation Value
• Relic neutrinos: Physically consistent treatment of effective number of neutrinos and neutrino mass
• The Abundance of Deuterium in the Warm Neutral Medium of the Lower Galactic Halo
• Nucleosynthesis Predictions and High-Precision Deuterium Measurements
• Time variation of the electron mass in the early universe and the Barrow-Magueijo model
• Chemical composition of two bright extremely metal-poor stars from the SDSS MARVELS pre-survey
• Testing Primordial Abundances With Sterile Neutrinos
• Non equilibrium dynamics of mixing, oscillations and equilibration: a model study
• Fugacity and Reheating of Primordial Neutrinos