#include "FTFP_BERT.hh"  			//Recommended for HEP applications
#include "QGSP_BIC_HP.hh"  			//Recommended for medical applications
#include "QGSP_BIC.hh"  			//No HP models for neutrons

#include "G4EmPenelopePhysics.hh"	//standard
#include "DecayPhysics.hh"			//custom
#include "OpticalPhotonPhysics.hh"	//custom

#include "MyModularPhysicsList.hh"  //custom PhysicsList derived from G4VModularPhysicsList
#include "PhysicsList.hh"           //custom PhysicsList derived from G4VUserPhysicsList


// ...


//In you main, when you have to set the mandatory initialization classes:

G4bool IWantMPL = false;
if (IWantMPL) {
	//Select a modular physics list (has the RegisterPhysics method):
	
	//method 1: Use the G4PhysListFactory and GetReferencePhysList method
	//G4PhysListFactory* physListFactory = new G4PhysListFactory();
	//G4VModularPhysicsList* physicsList = physListFactory->GetReferencePhysList("QGSP_BIC_HP");

	//method 2: call the constructor of the required ModularPhysicsList
	//QGSP_BIC* physicsList = new QGSP_BIC();
	MyModularPhysicsList* physicsList = new MyModularPhysicsList();
	
	//register new (custom) modules
    physicsList->RegisterPhysics(new DecayPhysics()); 
	physicsList->RegisterPhysics(new OpticalPhotonPhysics());
	//replace the defualt EM module of QGSP_BIC
	((physicsList->ReplacePhysics(new G4EmPenelopePhysics());
	
	runManager->SetUserInitialization(physicsList);
	
} else {
	//select user PhysicsList
	runManager->SetUserInitialization(new PhysicsList());
}


// ...