The List modus provides a modus for hydro afterburner calculations. It takes files with a list of particles in Oscar 2013 format as an input. These particles are treated as a starting setup. Multiple events per file are supported. In the following, the input keys are listed with a short description, an example is given and some information about the input particle files is provided.

Attention: In List modus, the provided list of particles has to match information contained in the particles file (either the SMASH default one or that provided via the -p option), when appropriate. In particular, the mass of stable particles has to match that of the particles file. In case of a mismatch, the latter is used (modifying its energy to put the particle back on shell) and the user warned. Furthermore, all particles have to be on their mass shell. If not, their energy is adjusted and the user warned. Note that this type of warning is given only once and it is user responsibility to ensure that this is a desired behaviour.

File_Directory — string, required

Directory for the external particle lists. Although relative paths to the execution directory should work, you are encouraged to prefer absolute paths.

Filename — string, required

External particle lists filename. This key shall be omitted if List: File_Prefix is used. By using this key, it is understood that all events to be processed are contained in the given file, as this is the only one which will be read.

File_Prefix — string, required

Prefix for the external particle lists file. This key shall be omitted if List: Filename is used.

Shift_Id — int, optional, default = 0

Index of the first processed particle list file. Files with index smaller than the specidifed value are skipped. This key is considered when List: File_Prefix is used to specify which particles list file(s) should be read. If, instead, the user specifies the List: Filename key, this key is ignored.

Configuring an afterburner simulation

The following example sets up an afterburner simulation for a set of particle files located in particle_lists_in folder. The files are named as event10, event11, etc. (the first being number 10 is specified by the key Shift_Id). SMASH is run once for each event in the folder.

Modi:
    List:
        File_Directory: "particle_lists_in"
        File_Prefix: "event"
        Shift_Id: 10

Alternatively, if all events are contained in a single file (or if only one file has to be processed), the following configuration can be used (SMASH will then read the particle_lists_in/single_file_to_be_used.dat file).

Modi:
    List:
        File_Directory: "particle_lists_in"
        Filename: "single_file_to_be_used.dat"

Some information about the structure of input particle file

This is how an input particle file might look like:

#!OSCAR2013 particle_lists t x y z mass p0 px py pz pdg ID charge
# Units: fm fm fm fm GeV GeV GeV GeV GeV none none none
0.1 6.42036 1.66473 9.38499 0.138 0.232871 0.116953 -0.115553 0.090303 111 0 0
# event 0 end
# event 1
0.1 6.42036 1.66473 9.38499 0.138 0.232871 0.116953 -0.115553 0.090303 111 0 0
# event 1 end

Each colum contains the described quantities. In particular, in the example above, one \(\pi^0\) with spatial coordinates

\[(t, x, y, z) = (0.1, 6.42036, 1.66473, 9.38499)\,\mathrm{fm}\]

and and 4-momenta

\[(p_0,p_x,p_y,p_z)=(0.232871,0.116953,-0.115553,0.090303)\,\mathrm{GeV}\]

with mass = 0.138 GeV, pdg = 111, id = 0 and charge 0 will be initialized for the first event (and also for the second event).

Note

SMASH is shipped with an example configuration file to set up an afterburner simulation by means of the list modus. This also requires a particle list to be read in. Both, the configuration file and the particle list, are located in the input/list folder at the top-level of SMASH codebase. To run SMASH with the provided example configuration and particle list, execute

   ./smash -i INPUT_DIR/list/config.yaml

where INPUT_DIR needs to be replaced by the path to the input directory at the top-level of SMASH codebase.