AlterAlterBBN

A modified (altered) version of AlterBBN (https://alterbbn.hepforge.org/) that can be used to calculate BBN constraints for a broader class of BSM scenarios.

Input	Output
param_file.dat	abundance_file.dat
cosmo_file.dat

How to compile and run

Compile via

./build.sh

and afterwards run with

./bin/alteralterbbn <io_directory>

Here, the command-line argument <io_directory> is optional. In case it is not provided, io/sm is used as default.

An example output of running ./bin/alteralterbbn would be

AlterAlterBBN v2.0

INFO   : Using the directory 'io/sm' to read and write data.
INFO   : Using eta = 6.13700e-10 from 'io/sm/param_file.dat'.
INFO   : Using cosmological data from 'io/sm/cosmo_file.dat'.
INFO   : Running nucleosynthesis...Done!
INFO   : The final abundances are:

     |     mean     |     high     |     low
-------------------------------------------------
   n | 0.000000e+00 | 0.000000e+00 | 0.000000e+00
   p | 7.532623e-01 | 7.533308e-01 | 7.531942e-01
  H2 | 1.882976e-05 | 1.842938e-05 | 1.924009e-05
  H3 | 6.028469e-08 | 5.846805e-08 | 6.218953e-08
 He3 | 7.718019e-06 | 7.778271e-06 | 7.663937e-06
 He4 | 6.166916e-02 | 6.165221e-02 | 6.168603e-02
 Li6 | 8.273444e-15 | 2.691357e-14 | 1.282041e-15
 Li7 | 2.201511e-11 | 2.229534e-11 | 2.161780e-11
 Be7 | 3.765608e-10 | 4.021330e-10 | 3.532403e-10

INFO   : The final abundances have been written to 'io/sm/abundance_file.dat'.

The param-file

AlterAlterBBN expects a param-file with name param_file.dat in <io_directory> with at least one line that reads eta=<eta>, e.g. eta=6.137e-10

The cosmo-file

AlterAlterBBN expects a cosmo-file with name cosmo_file.dat in <io_directory> with the column structure

• t in s
• T in MeV
• dTdt in MeV²
• Tnu in MeV
• H in MeV
• nb/etaf in MeV³

Note that this is different from how the original version of AlterAlterBBN handled the cosmo-file!