Projectile:
Section for projectile nucleus. The projectile will start at \(z < 0\) and fly in positive \(z\)-direction, at \(x \ge 0\).
Target:
Section for target nucleus. The target will start at \(z > 0\) and fly in negative \(z\)-direction, at \(x \le 0\).
Projectile:
and Target:
Particles
(int:int, int:int, required):Particles: {2212: 82, 2112: 126}
for a lead-208 nucleus (82 protons and 126 neutrons = 208 nucleons), and Particles: {2212: 1, 2112: 1, 3122: 1}
for Hyper-Triton (one proton, one neutron and one Lambda).Diffusiveness
(double, optional, default = (0.545 for A <= 16; 0.54 for A > 16)): Radius
(double, optional, default = 1.2 * A^(1/3) for A <= 16, else 1.12 * A^(1/3) - 0.86 * A^(-1/3)): Saturation_Density
(double, optional, default = 0.168): Deformed:
Automatic
(bool, required if Deformed
exists, no default): Beta_2
, Beta_4
, Theta
and Phi
, which follow Moller:1993ed [5] and Schenke:2019ruo [8]. Beta_2
(double, optional):Beta_4
(double, optional):Orientation
Phi
(double, optional, default = 0):Theta
(double, optional, default = pi/2): Random_Rotation
(bool, optional, default = false):Custom:
File_Directory
(path, required if Custom
exists): File_Name
(string, required if Custom
exists): Modi: Collider: Projectile: Particles: {2212: 29, 2112: 34} Deformed: # Manually set deformation parameters Automatic: False Beta_2: 0.1 Beta_4: 0.3 Orientation: Theta: 0.8 Phi: 0.02 Target: Particles: {2212: 29, 2112: 34} # manually set woods saxon parameters Saturation_Density: 0.1968 Diffusiveness: 0.8 Radius: 2.0 Deformed: # Automatically set deformation parameters Automatic: True Orientation: # Randomly rotate nucleus Random_Rotation: True E_kin: 1.2 Calculation_Frame: "fixed target"
Example: Configuring custom nuclei from external file
The following example illustrates how to configure a center-of-mass heavy-ion collision with nuclei generated from an external file. The nucleon positions are not sampled by smash but read in from an external file. The given path and name of the external file are made up and should be defined by the user according to the used file.
Modi: Collider: Projectile: Particles: {2212: 79, 2112: 118} Custom: File_Directory: "/home/username/custom_lists" File_Name: "Au197_custom.txt" Target: Particles: {2212: 79, 2112: 118} Custom: File_Directory: "/home/username/custom_lists" File_Name: "Au197_custom.txt" Sqrtsnn: 7.7
The following example shows how an input file should be formatted:
The input file contains 5 columns (x, y, z, s, c). The first three columns specify the spatial cordinates in fm. The fourth column denotes the spin projection. The fifth contains the charge with 1 and 0 for protons and neutrons respectively. In the example given the first line defines a neutron and the second one a proton. Please make sure that your file contains as many particles as you specified in the configuration. For the example configuration your file needs to contain 79 protons and 118 neutrons in the first 197 lines. And the same number in the following 197 lines. The read in nuclei are randomly rotated and recentered. Therefore you can run smash even if your file does not contain enough nuclei for the number of events you want to simulate as the missing nuclei are generated by rotation of the given configurations.
./smash -i INPUT_DIR/custom_nucleus/config.yaml