gener->SetOrigin(0,0,0); //vertex position
gener->SetSigma(0,0,0); //Sigma in (X,Y,Z) (cm) on IP position
gener->SetForceDecay(kSemiMuonic);
gener->SetOrigin(0,0,0); //vertex position
gener->SetSigma(0,0,0); //Sigma in (X,Y,Z) (cm) on IP position
gener->SetForceDecay(kSemiMuonic);