EIC code displayed by LXR |
|
|
|
|||
File indexing completed on 2026-08-06 09:24:09
0001 // -*- C++ -*- 0002 #ifndef HERWIG_MEPP2ZJet_H 0003 #define HERWIG_MEPP2ZJet_H 0004 // 0005 // This is the declaration of the MEPP2ZJet class. 0006 // 0007 0008 #include "Herwig/MatrixElement/HwMEBase.h" 0009 #include "ThePEG/Helicity/WaveFunction/SpinorWaveFunction.h" 0010 #include "ThePEG/Helicity/WaveFunction/VectorWaveFunction.h" 0011 #include "ThePEG/Helicity/WaveFunction/SpinorBarWaveFunction.h" 0012 #include "Herwig/MatrixElement/ProductionMatrixElement.h" 0013 #include "ThePEG/Helicity/Vertex/AbstractFFVVertex.fh" 0014 0015 namespace Herwig { 0016 0017 using namespace ThePEG; 0018 using namespace ThePEG::Helicity; 0019 0020 /** 0021 * The MEPP2ZJet class implements the matrix element for the production 0022 * of a Z boson + a jet including the decay of the Z including \f$Z/\gamma\f$ 0023 * interference 0024 * 0025 * @see \ref MEPP2ZJetInterfaces "The interfaces" 0026 * defined for MEPP2ZJet. 0027 */ 0028 class MEPP2ZJet: public HwMEBase { 0029 0030 public: 0031 0032 /** 0033 * The default constructor. 0034 */ 0035 MEPP2ZJet(); 0036 0037 /** @name Virtual functions required by the MEBase class. */ 0038 //@{ 0039 /** 0040 * Return the order in \f$\alpha_S\f$ in which this matrix 0041 * element is given. 0042 */ 0043 virtual unsigned int orderInAlphaS() const; 0044 0045 /** 0046 * Return the order in \f$\alpha_{EW}\f$ in which this matrix 0047 * element is given. 0048 */ 0049 virtual unsigned int orderInAlphaEW() const; 0050 0051 /** 0052 * The matrix element for the kinematical configuration 0053 * previously provided by the last call to setKinematics(), suitably 0054 * scaled by sHat() to give a dimension-less number. 0055 * @return the matrix element scaled with sHat() to give a 0056 * dimensionless number. 0057 */ 0058 virtual double me2() const; 0059 0060 /** 0061 * Return the scale associated with the last set phase space point. 0062 */ 0063 virtual Energy2 scale() const; 0064 0065 /** 0066 * The number of internal degrees of freedom used in the matrix 0067 * element. 0068 */ 0069 virtual int nDim() const; 0070 0071 /** 0072 * Generate internal degrees of freedom given nDim() uniform 0073 * random numbers in the interval \f$ ]0,1[ \f$. To help the phase space 0074 * generator, the dSigHatDR should be a smooth function of these 0075 * numbers, although this is not strictly necessary. 0076 * @param r a pointer to the first of nDim() consecutive random numbers. 0077 * @return true if the generation succeeded, otherwise false. 0078 */ 0079 virtual bool generateKinematics(const double * r); 0080 0081 /** 0082 * Return the matrix element squared differential in the variables 0083 * given by the last call to generateKinematics(). 0084 */ 0085 virtual CrossSection dSigHatDR() const; 0086 0087 /** 0088 * Add all possible diagrams with the add() function. 0089 */ 0090 virtual void getDiagrams() const; 0091 0092 /** 0093 * Get diagram selector. With the information previously supplied with the 0094 * setKinematics method, a derived class may optionally 0095 * override this method to weight the given diagrams with their 0096 * (although certainly not physical) relative probabilities. 0097 * @param dv the diagrams to be weighted. 0098 * @return a Selector relating the given diagrams to their weights. 0099 */ 0100 virtual Selector<DiagramIndex> diagrams(const DiagramVector & dv) const; 0101 0102 /** 0103 * Return a Selector with possible colour geometries for the selected 0104 * diagram weighted by their relative probabilities. 0105 * @param diag the diagram chosen. 0106 * @return the possible colour geometries weighted by their 0107 * relative probabilities. 0108 */ 0109 virtual Selector<const ColourLines *> 0110 colourGeometries(tcDiagPtr diag) const; 0111 0112 /** 0113 * Construct the vertex of spin correlations. 0114 */ 0115 virtual void constructVertex(tSubProPtr); 0116 //@} 0117 0118 public: 0119 0120 /** @name Functions used by the persistent I/O system. */ 0121 //@{ 0122 /** 0123 * Function used to write out object persistently. 0124 * @param os the persistent output stream written to. 0125 */ 0126 void persistentOutput(PersistentOStream & os) const; 0127 0128 /** 0129 * Function used to read in object persistently. 0130 * @param is the persistent input stream read from. 0131 * @param version the version number of the object when written. 0132 */ 0133 void persistentInput(PersistentIStream & is, int version); 0134 //@} 0135 0136 /** 0137 * The standard Init function used to initialize the interfaces. 0138 * Called exactly once for each class by the class description system 0139 * before the main function starts or 0140 * when this class is dynamically loaded. 0141 */ 0142 static void Init(); 0143 0144 protected: 0145 0146 /** 0147 * Matrix elements for the different subprocesses 0148 */ 0149 //@{ 0150 /** 0151 * Matrix element for \f$q\bar{q}\to Z/\gamma g\f$. 0152 * @param fin Spinors for incoming quark 0153 * @param ain Spinors for incoming antiquark 0154 * @param gout Polarization vectors for the outgoing gluon 0155 * @param lm Spinors for outgoing lepton 0156 * @param lp Spinors for outgoing antilepton 0157 * @param me Whether or not to calculate the matrix element for spin correlations 0158 **/ 0159 InvEnergy2 qqbarME(vector<SpinorWaveFunction> & fin, 0160 vector<SpinorBarWaveFunction> & ain, 0161 vector<VectorWaveFunction> & gout, 0162 vector<SpinorBarWaveFunction> & lm, vector<SpinorWaveFunction> & lp, 0163 bool me=false) const; 0164 0165 /** 0166 * Matrix element for \f$qg\to Z/\gamma q\f$. 0167 * @param fin Spinors for incoming quark 0168 * @param gin Polarization vectors for the incoming gluon 0169 * @param fout Spinors for outgoing quark 0170 * @param lm Spinors for outgoing lepton 0171 * @param lp Spinors for outgoing antilepton 0172 * @param me Whether or not to calculate the matrix element for spin correlations 0173 **/ 0174 InvEnergy2 qgME(vector<SpinorWaveFunction> & fin,vector<VectorWaveFunction> & gin, 0175 vector<SpinorBarWaveFunction> & fout, 0176 vector<SpinorBarWaveFunction> & lm, vector<SpinorWaveFunction> & lp, 0177 bool me=false) const; 0178 0179 /** 0180 * Matrix element for \f$\bar{q}g\to Z/\gamma\bar{q}\f$. 0181 * @param fin Spinors for incoming antiquark 0182 * @param gin Polarization vectors for the incoming gluon 0183 * @param fout Spinors for outgoing antiquark 0184 * @param lm Spinors for outgoing lepton 0185 * @param lp Spinors for outgoing antilepton 0186 * @param me Whether or not to calculate the matrix element for spin correlations 0187 **/ 0188 InvEnergy2 qbargME(vector<SpinorBarWaveFunction> & fin, 0189 vector<VectorWaveFunction> & gin, 0190 vector<SpinorWaveFunction> & fout, 0191 vector<SpinorBarWaveFunction> & lm, vector<SpinorWaveFunction> & lp, 0192 bool me=false) const; 0193 //@} 0194 0195 protected: 0196 0197 /** @name Clone Methods. */ 0198 //@{ 0199 /** 0200 * Make a simple clone of this object. 0201 * @return a pointer to the new object. 0202 */ 0203 virtual IBPtr clone() const { return new_ptr(*this); } 0204 0205 /** Make a clone of this object, possibly modifying the cloned object 0206 * to make it sane. 0207 * @return a pointer to the new object. 0208 */ 0209 virtual IBPtr fullclone() const { return new_ptr(*this); } 0210 //@} 0211 0212 protected: 0213 0214 /** @name Standard Interfaced functions. */ 0215 //@{ 0216 /** 0217 * Initialize this object after the setup phase before saving an 0218 * EventGenerator to disk. 0219 * @throws InitException if object could not be initialized properly. 0220 */ 0221 virtual void doinit(); 0222 //@} 0223 0224 private: 0225 0226 /** 0227 * The assignment operator is private and must never be called. 0228 * In fact, it should not even be implemented. 0229 */ 0230 MEPP2ZJet & operator=(const MEPP2ZJet &) = delete; 0231 0232 private: 0233 0234 /** 0235 * Vertices for the helicity amplitude calculation 0236 */ 0237 //@{ 0238 /** 0239 * Pointer to the Z vertex 0240 */ 0241 AbstractFFVVertexPtr _theFFZVertex; 0242 0243 /** 0244 * Pointer to the photon vertex 0245 */ 0246 AbstractFFVVertexPtr _theFFPVertex; 0247 0248 /** 0249 * Pointer to the \f$qqg\f$ vertex 0250 */ 0251 AbstractFFVVertexPtr _theQQGVertex; 0252 //@} 0253 0254 /** 0255 * @name Pointers to the \f$Z^0\f$ and \f$\gamma\f$ ParticleData objects 0256 */ 0257 //@{ 0258 /** 0259 * Pointer to the Z ParticleData object 0260 */ 0261 tcPDPtr _z0; 0262 0263 /** 0264 * Pointer to the photon ParticleData object 0265 */ 0266 tcPDPtr _gamma; 0267 //@} 0268 0269 /** 0270 * @name Switches to control the particles in the hard process 0271 */ 0272 //@{ 0273 /** 0274 * Subprocesses to include 0275 */ 0276 unsigned int _process; 0277 0278 /** 0279 * Allowed flavours for the incoming quarks 0280 */ 0281 int _maxflavour; 0282 0283 /** 0284 * Control over which Z decay modes to include 0285 */ 0286 int _zdec; 0287 0288 /** 0289 * Which terms to include 0290 */ 0291 unsigned int _gammaZ; 0292 0293 /** 0294 * Option for the treatment of the W off-shell effects 0295 */ 0296 unsigned int _widthopt; 0297 //@} 0298 0299 /** 0300 * Probability of selecting \f$1/s^2\f$ for the jacobian 0301 * transformation of the boson mass 0302 */ 0303 double _pprob; 0304 0305 /** 0306 * Matrix element for spin correlations 0307 */ 0308 mutable ProductionMatrixElement _me; 0309 0310 /** 0311 * Storage of the scale to avoid the need to recalculate 0312 */ 0313 Energy2 _scale; 0314 0315 /** 0316 * Storage of the off-shell Z mass to avoid the need to recalculate 0317 */ 0318 Energy2 _mz2; 0319 }; 0320 0321 } 0322 0323 #endif /* HERWIG_MEPP2ZJet_H */
| [ Source navigation ] | [ Diff markup ] | [ Identifier search ] | [ general search ] |
|
This page was automatically generated by the 2.3.7 LXR engine. The LXR team |
|