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Manuscript Title: A track reconstruction program (TRP) for evaluation of nucleus- nucleus collisions in nuclear track emulsion chambers.
Authors: E. Ganssauge, B. Dressel, S. Hackel, H. Kallies, E. Koch, Ch. Muller, J.T. Rhee, W. Schulz, K. Standecke
Program title: VERT VER. 3.1, EMUFIT VER. 4.1
Catalogue identifier: ABFU_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 55(1989)233
Programming language: Fortran.
Computer: VAX 11-750.
Operating system: VAX-VMS 4.7.
RAM: 6000K words
Word size: 32
Keywords: Particle physics, Elementary, Event reconstruction, High-multiplicity events, Vertex-determination, Emulsion-chamber.
Classification: 11.9.

Nature of problem:
In high energy heavy ion physics nucleus-nucleus collisions produce particles moving in a narrow cone along the beam axis. In a typical experiment using emulsion chambers with gold targets there are multiplicities of singly charged particles observed of the order of 500. The beam was in this case 32S of 200 GeV/nucleon.

Solution method:
In the perpendicularly exposed chambers there are samples of points in the different emulsion layers showing up after processing. These points stem partially from the tracks of the secondary particles produced by the primary collision, partially they are just background from different sources. The program has to reduce the background and to combine the "real" measured points to tracks coming from a common vertex point. VERT determines the vertex as the most probable point for a maximum number of tracks, and EMUFIT reconstructs the single tracks.

Running time:
The running time depends on the mutliplicity n ch of the event. Some examples (EMUFIT):
n ch ^ 150 : 120 s / event
n ch ^ 300 : 170 s / event
n ch ^ 450 : 420 s / event