// Example from the Oxbridge Stransverse Mass Library -- oxbridgekinetics. // See http://www.hep.phy.cam.ac.uk/~lester/mt2/index.html // Authors: Christopher Lester and Alan Barr #include "ExampleEvent.h" #include "Mt2/Basic_Mt2_AsymmParents332_Calculator.h" #include int main(int argc, char * argv[]) { // For the example. we now need some momenta and masses from which // to calculate MT2. // // In "reality" we would get these momenta from an ntuple or // from a physics event. // // As this is just an example program, we will instead get // some "example" momenta from the class "ExampleEvent" // defined in "ExampleEvent.h"as follows: ExampleEvent exampleEvent; Mt2::LorentzTransverseVector ltv_Vis_A = exampleEvent. ltv_Vis_A(); Mt2::LorentzTransverseVector ltv_Vis_B = exampleEvent. ltv_Vis_B(); Mt2::TwoVector pT_Miss = exampleEvent. pT_Miss(); const double invis_mass = exampleEvent.invis_mass(); const double theta=atan(1.); std::cout << "Going to calculate MT2 with\n" << " ltv_Vis_A = " << ltv_Vis_A << "\n" << " ltv_Vis_B = " << ltv_Vis_B << "\n" << " pT_Miss = " << pT_Miss << "\n" << " invis_mass = " << invis_mass << "\n" << " theta = " << theta << " which is " << theta-3.14159/4 << " from pi/4" << std::endl; // Now that we have some visiable momenta and some missing transverse // momentum we can calculate MT2. // First we create the object that is going to do the calculation // of MT2 for us. // // For this example we will use a modification of the "332" aglorithm // that was originally defined in SUSYPhys. Our modification (called // Basic_Mt2_AsymmParents332_Calculator) is basically the same as // SUSYPhys_Mt2_222_Calculator except that we remove the assumption // that visible particles are massless. Mt2::Basic_Mt2_AsymmParents332_Calculator mt2Calculator; // Could tell the MT2 calculating object to be verbose, and print out // debug messages while it is thinking ... but we won't: // mt2Calculator.setDebug(true); // Now we can actually calculate MT2: const double mt2 = mt2Calculator.mt2_AsymmParents332(theta, ltv_Vis_A, ltv_Vis_B, pT_Miss, invis_mass); // Now we print out the result: std::cout << "ANSWER: mt2 = " << mt2 << " for " << mt2Calculator.algorithmName() << " algorithm with theta= "<< theta << std::endl; return 0; }