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Herwig  7.2.1
MG_gg2ttxg.h
1 // -*- C++ -*-
2 //
3 // MG_gg2ttxg.h is a part of Herwig - A multi-purpose Monte Carlo event generator
4 // Copyright (C) 2002-2019 The Herwig Collaboration
5 //
6 // Herwig is licenced under version 3 of the GPL, see COPYING for details.
7 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
8 //
9 #ifndef MG5_Sigma_sm_gg2ttxg_H
10 #define MG5_Sigma_sm_gg2ttxg_H
11 //
12 // This is the declaration of the MG_gg2ttxg class.
13 //
14 
15 #include <complex>
16 #include <vector>
17 #include "Parameters_sm.h"
18 
19 using namespace std;
20 
21 
23 {
24  public:
25 
26  // Constructor.
27  MG_gg2ttxg() {}
28 
29  // Initialize process using Herwig parameters
30  virtual void initProc(map<string, double> & MGParams);
31 
32  // Calculate flavour-independent parts of cross section.
33  virtual void sigmaKin(vector<std::complex<double> >& amps, const vector<int>& hel);
34 
35  // Set momenta for matrix element evaluation
36  void setMomenta(vector < double * > & momenta){p = momenta;}
37 
38  // number of external particles
39  static const int nexternal = 5;
40 
41  // number of colour ordered amplitudes
42  static const int namplitudes = 18;
43  std::complex<double> amp[namplitudes];
44 
45  private:
46  // Calculate wavefunctions
47  void calculate_wavefunctions(const int perm[], const int hel[]);
48 
49  // number of wavefunctions used in calculate_wavefunctions
50  static const int nwavefuncs = 18;
51  std::complex<double> w[nwavefuncs][18];
52 
53  // Pointer to the model parameters
54  Parameters_sm * pars;
55 
56  // vector with external particle masses
57  vector<double> mME;
58 
59  // vector with momenta
60  vector < double * > p;
61 
62 };
63 
64 
65 #endif // MG5_Sigma_sm_gg2ttxg_H
STL namespace.