PRIMAT

General description

PRIMAT is a Mathematica code dedicated to the computation of light elements abundances at the end of the Big-Bang Nucleosynthesis (BBN). It computes the evolution of these abundances in the first minutes after the Big-Bang so as to obtain the frozen values when the temperature dropped below 10⁸ degrees. It allows to explore the dependence of light elements abundances on cosmological parameters, such as baryon density or number of neutrino species, but also to estimate from a Monte-Carlo method the uncertainty in these predictions due to uncertainties in nuclear reaction rates. It is tested for Mathematica 13.x.y and 14.x.y but used to work on earlier versions.

Documentation

The details of the method used to solve numerically for the thermodynamics, cosmology and nuclear reactions in the early universe are available in an Physics Reports article (04, (2018) 005 [arXiv:1801.08023]). Please cite it along with this website if you use it in BBN related publications, using this bibtex file. See also updates on rates described in MNRAS 502 (2021) 2474-2481 [arXiv:2011.11320].

A PDF dump of the notebook is provided in the package if you wish only to consult the code without opening Mathematica. The code is commented and refers to equations in the Physics Reports article.

New ! : PRIMAT can be called within python, and a folder provides brief examples.

Downloading

You can download the latest and previous versions of PRIMAT (see README file inside).
Modifications and evolutions are listed in the HistoryVersions.txt file.

• PRIMAT 0.3.0 (2024)

• PRIMAT 0.2.3 (2024)
• PRIMAT 0.2.2 (2023)
• PRIMAT 0.1.2 (2019)
• PRIMAT 0.1.1 (2018)
• PRIMAT 0.1.0 (2018)

Some examples are provided in the Example folder. Three basic examples explain how to get the final abundances, output them in files, and draw some plots. Other more advanced examples perform computations on a grid of parameters or MCMC estimations of uncertainties, or both. This can take a long time even using parallelization over several Kernels. Hence you can also download the previously stored results of the Results folder. You can place this folder inside PRIMAT folder (0.3.0 version only), and when running the example notebooks, then you must skip the cell launching long computations and you proceed with the subsequent cells which load and analyze the results.

Results

A table of main abundances (He-4 and Deuterium) as a function of baryons abundance and effective number of neutrinos, which was generated with PRIMAT, is provided but it is also available as a direct download : PRIMAT_Yp_DH_ErrorMC_100_2024.dat

You can also consult the list of articles which acknowledge the use of PRIMAT.

CopyLeft

The programs in this page are distributed as free software under the GNU General Public License. They are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU GPL for more details.