The current dark brem simulation uses a reference library of MadGraph-generated events to simulate the outgoing kinematics after Geant4 determines that a dark brem should happen within a given material. Currently, this reference library has only a single axis - the incident energy of the electron. This has proven successful for simulating a wide range of incident electron energies due to various upstream interactions occuring. Adding another axis to the library corresponding to the atomic number (Z) of the nucleus that the dark brem was generated within MG with would allow this implementation of dark brem to happen realistically in a material that has a wider variety of atoms in it (most importantly, a potential active target made of LYSO and materials within the ECal like PCB).
Expected Changes
[x] Update LHE reader to extract the atomic number alongside the incident energy, recoil pT and recoil KE fraction
[x] Introduce a method for random selection of atom when a composite material is chosen to dark brem
probably relying on xsec-weighted random selection
[x] Choose outgoing kinematics based on nearest incident energy and nearest Z
materials close-in-Z pretty realistically model each other according to MG, so we don't need to have a library entry for each unique atom
The current dark brem simulation uses a reference library of MadGraph-generated events to simulate the outgoing kinematics after Geant4 determines that a dark brem should happen within a given material. Currently, this reference library has only a single axis - the incident energy of the electron. This has proven successful for simulating a wide range of incident electron energies due to various upstream interactions occuring. Adding another axis to the library corresponding to the atomic number (Z) of the nucleus that the dark brem was generated within MG with would allow this implementation of dark brem to happen realistically in a material that has a wider variety of atoms in it (most importantly, a potential active target made of LYSO and materials within the ECal like PCB).
Expected Changes