Standard Big-Bang Nucleosynthesis after Planck

TL;DR

This paper updates Big Bang nucleosynthesis predictions using Planck data, refining element abundance estimates with improved nuclear models and observations, confirming the consistency of BBN with cosmological measurements.

Contribution

It provides revised BBN predictions incorporating Planck's baryonic density and improved nuclear data, with narrower error margins and updated primordial element abundances.

Findings

Narrower error bars for D/H primordial abundance

Slight reduction in primordial Li/H abundance

Primordial Helium abundance determined as Y_p=0.2463±0.0003

Abstract

Primordial or Big Bang nucleosynthesis (BBN) is one of the three historical strong evidences for the Big-Bang model together with the expansion of the Universe and the Cosmic Microwave Background radiation (CMB). The recent results by the Planck mission have slightly changed the estimate of the baryonic density Omega_b, compared to the previous WMAP value. This article updates the BBN predictions for the light elements using the new value of Omega_b determined by Planck, as well as an improvement of the nuclear network and new spectroscopic observations. While there is no major modification, the error bars of the primordial D/H abundance (2.67+/-0.09) x 10^{-5} are narrower and there is a slight lowering of the primordial Li/H abundance (4.89^+0.41_-0.39) x 10^{-10}. However, this last value is still ~3 times larger than its observed spectroscopic abundance in halo stars of the Galaxy. Primordial Helium abundance is now determined to be Y_p = 0.2463+/-0.0003.