This is very preliminary and simplified Geant4 example for light dark matter (LDM) particles. It consists of LDM bremsstrahlung process (in G4LDMPhysics constructor) for protons creating G4LDMPhotons. The latter decays creating G4LDMHi and G4LDMHiBar LDM scalar particles. They can scatter on nucleons and electrons.

The first version has electromagnetic processes only. Hadron constructors can be added similarly to HadrN examples.

More LDM processes will be added according to experiment requirements

GEOMETRY DEFINITION

The geometry consists of a single block of a homogenous material, placed in a world.

Parameters define the geometry :

the material of the box
the thickness of the box
the tranverse dimension of the box

The default is 130 cm of tungsten. Equivalent UI commands are following:

/testex/det/setMat G4_W
/testex/det/sizeX  130 cm
/testex/det/sizeYZ  30 cm

The default geometry is constructed in DetectorConstruction class, but all of the above parameters can be changed interactively via the commands defined in the DetectorMessenger class.

PHYSICS LIST

Physics Lists include EM standard physics and decay physics, additional dark matter particle physics imlemented inside PhysicsList method. By default DMLPhoton is defined with the mass 0.5 GeV. To define different mass of this photon or enable DMLHi, DMLHiBar command line commands should be applied.

THE PRIMARY GENERATOR

The primary kinematic consists of a single particle which hits the block perpendicular to the input face. The type of the particle and its energy are set in the PrimaryGeneratorAction class, and can changed via the G4 build-in commands of ParticleGun class (see the macros provided with this example). The default is proton 100 GeV

HOW TO START ?

Execute Test in 'batch' mode from macro files

% dmparticle dmparticle.in
% dmparticle dmparticle.in 0.2 0.4

two extra numbers are masses in GeV of DMLPhoton and DMLHi