AlterBBN Version 2.2 (18th July 2019)
--------------------------------------
By Alexandre Arbey (alexandre.arbey@ens-lyon.fr), Jeremy Auffinger (jeremy.auffinger@ens-lyon.fr), Kevin Hickerson (kevinh@caltech.edu) and Espen Jenssen (EspenJenssen@hotmail.com)


INTRODUCTION
------------
The most recent version of this program can be obtained from: 
https://alterbbn.hepforge.org/

This C code (in C99 standard) provides the calculation of the BBN abundance of the elements in different cosmological frameworks.

The program has been tested on Linux, Mac and Windows machines with gcc, clang and icc.


If you use AlterBBN to write a paper, please cite: 
A. Arbey, arXiv:1106.1363 [astro-ph.CO], Comput. Phys. Commun. 183 (2012) 1822
AND
A. Arbey, J. Auffinger, K. P. Hickerson, E. S. Jenssen, arXiv:1806.11095 [astro-ph.CO].


Installation and Compilation
----------------------------
- tar xzvf alterbbn_vX.X.tgz
- cd alterbbn_vX.X
- in Makefile, define your C compiler
- compile with: make

9 programs are available:
- stand_cosmo.c: calculation of the abundances in the standard cosmological model
- alter_eta.c: calculation in a scenario with a modified baryon-to-photon ratio
- alter_etannutau.c: calculation in a scenario with a modified baryon-to-photon ratio, a different number of neutrinos and a modified neutron lifetime
- alter_neutrinos.c: calculation in a scenario with a different number of neutrinos
- alter_phi.c: calculation in a scenario with a decaying scalar field
- alter_reheating.c: calculation in a model with modified expansion rate and reheating
- alter_standmod.c: calculation in a model with modified expansion rate and entropy content
- alter_wimps.c: calculation in a model where WIMPs can alter the nuclear rates
- alter_neutron.c: calculation in a model that require precise alteration of neutron to proton beta rates

Remark: if "Segmentation faults" are generated, please try to increase the stack size (ulimit -s unlimited).


Included Files
--------------
- Procedures in src/
bbn.c
bbnrate.c
bbn_constraints.c
general.c
cosmodel.c

- Main programs
stand_cosmo.c: calculation of the abundances in the standard cosmological model
alter_eta.c: calculation in a scenario with a modified baryon-to-photon ratio
alter_etannutau.c: calculation in a scenario with modified baryon-to-photon ratio, neutrino number and neutron lifetime
alter_neutrinos.c: calculation in a scenario with a different number of neutrinos, and/or with degeneracy
alter_phi.c: calculation in a scenario with a decaying scalar field
alter_reheating.c: calculation in a model with modified expansion rate and reheating
alter_standmod.c: calculation in a model with modified expansion rate and entropy content
alter_wimps.c: calculation in a model where WIMPs can alter the nuclear rates
alter_neutron.c: calculation in a model that require precise alteration of neutron to proton beta rates

- Headers in src
include.h: definitions and prototypes

- src/sgStar_heff/: contains different tables of sgStar/heff.

- Other
Makefile(s)
README


History
-------
v2.2 - 07/18/2019 -     Changed constraint routines.
			Corrected equivalent neutrino density derivative for non-WIMP scenarios (thanks to Felix Kahlhoefer and Patrick Stöcker).
			Small improvements.

v2.1 - 05/02/2019 -     Upgraded proton to neutron beta calculations.
			Added a new executable for altering neutron beta rates, alter_neutron.
			Repaired np beta code to correctly normalize to neutron lifetime.
			Added Fermi functions to np beta rates.
			Added Fierz interference term to np beta rates.
			Improved neutrino decoupling.
			Allowed scaling of samples used to compute np beta rates.
			Precise calculation (failsafe=1) set as default.
			New numerical integration methods added.
			Interface with the REACLIB database added to expand the nuclear network.
			Many improvements and small corrections.

v2.0 - 06/29/2018 -     Extended nuclear network.
			Several cases of WIMPs added.
			Automatic error and correlation calculation added.
			Scenario with decaying scalar field added.
			Scenario with reheating added.
			Multiprocessors option for faster error calculation.

v1.4 - 06/28/2013 -     Added calculation of the errors, inspired by astro-ph/9803177 (thanks to S. Sarkar).
			Routine prototypes modified.
			Neutrino degeneracy added.

v1.3 - 03/04/2012 -     Reaction rate moved to separate file bbnrate.c.
			Evaluation of errors using low and high rates.
			Several comments modified in the .c files (thanks to A. Mishra).

v1.2 - 07/08/2011 -     Improved p <-> n reaction rate.

v1.1 - 06/20/2011 -     Improved nuclear network.

v1.0 - 06/02/2011 - 	First public release.


LICENSE
-------
    AlterBBN Copyright (C) 2019 A. Arbey, J. Auffinger, K. Hickerson, E. Jenssen

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or any 
    later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    See <http://www.gnu.org/licenses/>.