Update documentation with new configuration parameters

Author: RobMina

docs/configuration.md

@@ -25,16 +25,21 @@ There are other parameters that tune the functionality of the simulation,
 but the parameters listed here are directly related to how the physics
 of the simulation is done.
 
-Parameter            | Required | Location              | Description
----------------------|----------|-----------------------|-------------
-A' Mass              | Yes      | G4APrime              | Mass of dark photon in MeV
-MG/ME Data           | Yes      | g4db::G4DarkBreMModel | Library of dark brem events
-Use Muons            | Yes      | g4db::G4DarkBreMModel | Choice to dark brem off muons or electrons
-Minimum DB Threshold | No       | g4db::G4DarkBreMModel | Minimum energy in GeV lepton needs to have to DB (default twice A' mass)
-Mixing Strength      | No       | g4db::G4DarkBreMModel | Mixing strength between dark photon and SM photon (default 1.0)
-Scaling Method       | No       | g4db::G4DarkBreMModel | Choice of how to scale the outgoing kinematics from the library (default ForwardOnly)
-Xsec Method          | No       | g4db::G4DarkBreMModel | Choice of WW approximation variant to calculate the total cross section. Options include Full, Improved, HyperImproved, and Auto (default is Auto where Full is used if the A' to lepton mass ratio is below the max and Improved is used otherwise)
-Maximum mass ratio   | No       | g4db::G4DarkBreMModel | If using Auto Xsec Method, the maximum ratio of A' to lepton mass to transition from Full WW to Improved WW (default 50.0)
-A' LHE ID            | No       | g4db::G4DarkBreMModel | If MG/ME Data is in the form of LHE files, the PDG ID of the A' inside of those files (default 622)
-Only One per Event   | No       | G4DarkBremsstrahlung  | Limit the dark brem process to only one interaction per event (default false)
-Global Bias          | No       | G4DarkBremsstrahlung  | Bias the dark brem process everywhere by this factor (default 1.0)
+Parameter             | Required | Location              | Description
+----------------------|----------|-----------------------|-------------
+A' Mass               | Yes      | G4APrime              | Mass of dark photon in MeV
+A' tau                | No       | G4APrime              | Proper lifetime of dark photon in seconds, only relevant if decay mode is set to GeantDecay (default -1, meaning no decay)
+Decay Mode            | No       | G4APrime              | Choice of whether to allow the A' to decay and the decay distribution. The only decay channel is e+/e- (default NoDecay)
+MG/ME Data            | Yes      | g4db::G4DarkBreMModel | Library of dark brem events
+Use Muons             | Yes      | g4db::G4DarkBreMModel | Choice to dark brem off muons or electrons
+Minimum DB Threshold  | No       | g4db::G4DarkBreMModel | Minimum energy in GeV lepton needs to have to DB (default twice A' mass)
+Mixing Strength       | No       | g4db::G4DarkBreMModel | Mixing strength between dark photon and SM photon (default 1.0)
+Scaling Method        | No       | g4db::G4DarkBreMModel | Choice of how to scale the outgoing kinematics from the library (default ForwardOnly)
+Xsec Method           | No       | g4db::G4DarkBreMModel | Choice of WW approximation variant to calculate the total cross section. Options include Full, Improved, HyperImproved, and Auto (default is Auto where Full is used if the A' to lepton mass ratio is below the max and Improved is used otherwise)
+Maximum mass ratio    | No       | g4db::G4DarkBreMModel | If using Auto Xsec Method, the maximum ratio of A' to lepton mass to transition from Full WW to Improved WW (default 50.0)
+A' LHE ID             | No       | g4db::G4DarkBreMModel | If MG/ME Data is in the form of LHE files, the PDG ID of the A' inside of those files (default 622)
+Scale A'              | No       | g4db::G4DarkBreMModel | Whether to scale the outgoing dark photon energy along with the recoil lepton (default false, meaning the dark photon will conserve total momentum while ignoring the nuclear recoil)
+Min A' decay distance | No       | g4db::G4DarkBreMModel | When A' decay mode is set to FlatDecay, this is the minimum lab-frame distance in mm the A' will travel before decaying (default 0)
+Max A' decay distance | No       | g4db::G4DarkBreMModel | When A' decay mode is set to FlatDecay, this is the maximum lab-frame distance in mm the A' will travel before decaying (default 1)
+Only One per Event    | No       | G4DarkBremsstrahlung  | Limit the dark brem process to only one interaction per event (default false)
+Global Bias           | No       | G4DarkBremsstrahlung  | Bias the dark brem process everywhere by this factor (default 1.0)