Old format (TXOLD) is very simple. It includes two types of the input lines:
All lines are free formatted, Ntrack, Nevent, ge_pid are positive integers, momentum components are in GeV/c. Vertex is supposed to be in one place for the whole event and is controlled by VXYZ/VSIG commands (See HELP USER).
HERE is an example of an input event containing 3 particles - photon, electron and muon :
event 3 1
1 1.000 0.500 0.200
3 1.100 0.100 0.600
5 0.600 0.900 0.300
GENER: eg_version east_z east_a west_z west_a sqrts b_max
- eg_version is a real number
- east_z etc. are the charge and mass of "projectiles"
- sqrt_s is CM energy (GeV) per nucleon (real)
- bmax is the maximum impact parameter used to generate the events (real)
EVENT: event_id n_tracks n_vertices
where event_id is an integer giving a label to the event which is unique within the file, n_tracks gives the number of tracks in the file associated with the event, and n_vertices gives the number of vertices. It is not necessary to specify any vertices, so that n_vertices = 0 is allowed. In this case all tracks are understood to be emitted from the same vertex positioned according to the VXYZ/VSIG command.
The event_id should be a positive integer. The file may be terminated with an event line having event_id <= -999 which is considered as end_of_file flag
TRACK: ge_pid px py pz track_id start_vertex stop_vertex eg_pid
- ge_pid is the Geant PID code for the track, or zero if its particle type is not known to GSTAR (in which case it will be passed through Geant to the output tables without being propagated through the detector)
- px, py, pz constitute the three-momentum of the track
- track_id is an integer label of the track which is unique within the event. It is not used by Geant and is simply passed through to the output tables.
- start_vertex and stop_vertex are the vertex_ids of the vertices where the track is born and dies. If the track does not die within the generated event, stop_vertex = 0. If start_vertex is not specified, all tracks in the event are assigned to a single primary vertex at the origin.
- eg_pid is an integer code to be used by the event generator giving the particle type using its own scheme, possibly different from GSTAR. It is not used by GSTAR and is simply passed through to the output tables.
VERTEX: x y z t vertex_id process parent_track n_daughters
- x,y,z,t is the space-time coordinate of the vertex in centimeters and seconds.
- vertex_id is a integer label unique within the event. The start_vertex and stop_vertex fields of the TRACK line refer to this field.
- process is an arbitrary label specified by the event generator to denote the physical process that generated this vertex. It is not used by Geant and is simply passed to the output tables.
- parent_track is the track_id of the parent track of the vertex, i.e. the one that was killed at the vertex.
- n_daughters is the number of daughter tracks produced by the vertex.
EVENT: 20 14 2
VERTEX: -2.50 -197.40 32.00 0.00 1 0 0 7
TRACK: 170 1.132769 1.398853 0.004712 1 1 0 1
TRACK: 170 1.519299 4.129333 -0.013055 2 1 0 1
TRACK: 170 4.005101 11.310058 -0.144499 3 1 0 1
TRACK: 170 -0.020416 4.499120 -0.061253 4 1 0 1
TRACK: 170 -4.307866 13.102446 -0.322629 5 1 0 1
TRACK: 170 -2.401932 5.497806 -0.049216 6 1 0 1
TRACK: 170 -4.575697 5.941664 -0.069373 7 1 0 1
VERTEX: -2.90 -197.40 60.00 0.00 2 0 0 7
TRACK: 170 46.249561 23.769043 -0.072606 8 2 0 1
TRACK: 170 11.140220 11.062716 -0.030142 9 2 0 1
TRACK: 170 1.004740 4.283729 0.009215 10 2 0 1
TRACK: 170 0.356125 37.097881 0.123027 11 2 0 1
TRACK: 170 -3.998152 17.960310 0.032114 12 2 0 1
TRACK: 170 -6.327198 14.586355 0.086026 13 2 0 1
TRACK: 170 -57.057911 56.070648 0.488680 14 2 0 1