Builtin/Amplitudes/MG_gg2ttxg.h

0001 // -*- C++ -*-
0002 //
0003 // MG_gg2ttxg.h is a part of Herwig - A multi-purpose Monte Carlo event generator
0004 // Copyright (C) 2002-2019 The Herwig Collaboration
0005 //
0006 // Herwig is licenced under version 3 of the GPL, see COPYING for details.
0007 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
0008 //
0009 #ifndef MG5_Sigma_sm_gg2ttxg_H
0010 #define MG5_Sigma_sm_gg2ttxg_H
0011 //
0012 // This is the declaration of the MG_gg2ttxg class.
0013 //
0014
0015 #include <complex>
0016 #include <vector>
0017 #include "Parameters_sm.h"
0018
0019 using namespace std;
0020
0021
0022 class MG_gg2ttxg
0023 {
0024   public:
0025
0026     // Constructor.
0027     MG_gg2ttxg() {}
0028
0029     // Initialize process using Herwig parameters
0030     virtual void initProc(map<string, double> & MGParams);
0031
0032     // Calculate flavour-independent parts of cross section.
0033     virtual void sigmaKin(vector<std::complex<double> >& amps, const vector<int>& hel);
0034
0035     // Set momenta for matrix element evaluation
0036     void setMomenta(vector < double * > & momenta){p = momenta;}
0037
0038     // number of external particles
0039     static const int nexternal = 5;
0040
0041     // number of colour ordered amplitudes
0042     static const int namplitudes = 18;
0043     std::complex<double> amp[namplitudes];
0044
0045   private:
0046     // Calculate wavefunctions
0047     void calculate_wavefunctions(const int perm[], const int hel[]);
0048
0049     // number of wavefunctions used in calculate_wavefunctions
0050     static const int nwavefuncs = 18;
0051     std::complex<double> w[nwavefuncs][18];
0052
0053     // Pointer to the model parameters
0054     Parameters_sm * pars;
0055
0056     // vector with external particle masses
0057     vector<double> mME;
0058
0059     // vector with momenta
0060     vector < double * > p;
0061
0062 };
0063
0064
0065 #endif  // MG5_Sigma_sm_gg2ttxg_H