[819] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // |
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| 27 | // $Id: G4QGSMFragmentation.cc,v 1.6 2007/04/24 14:55:23 gunter Exp $ |
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| 28 | // GEANT4 tag $Name: geant4-09-01-patch-02 $ |
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| 29 | // |
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| 30 | // ----------------------------------------------------------------------------- |
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| 31 | // GEANT 4 class implementation file |
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| 32 | // |
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| 33 | // History: first implementation, Maxim Komogorov, 10-Jul-1998 |
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| 34 | // ----------------------------------------------------------------------------- |
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| 35 | #include "G4QGSMFragmentation.hh" |
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| 36 | #include "G4FragmentingString.hh" |
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| 37 | #include "G4DiQuarks.hh" |
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| 38 | #include "G4Quarks.hh" |
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| 39 | |
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| 40 | #include "Randomize.hh" |
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| 41 | #include "G4ios.hh" |
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| 42 | |
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| 43 | // Class G4QGSMFragmentation |
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| 44 | //**************************************************************************************** |
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| 45 | |
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| 46 | G4QGSMFragmentation::G4QGSMFragmentation() : |
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| 47 | arho(0.5), aphi(0.), an(-0.5), ala(-0.75), aksi(-1.), alft(0.5) |
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| 48 | { |
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| 49 | } |
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| 50 | |
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| 51 | G4QGSMFragmentation::G4QGSMFragmentation(const G4QGSMFragmentation &) : G4VLongitudinalStringDecay(), |
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| 52 | arho(0.5), aphi(0.), an(-0.5), ala(-0.75), aksi(-1.), alft(0.5) |
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| 53 | { |
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| 54 | } |
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| 55 | |
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| 56 | G4QGSMFragmentation::~G4QGSMFragmentation() |
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| 57 | { |
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| 58 | } |
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| 59 | |
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| 60 | //**************************************************************************************** |
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| 61 | |
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| 62 | const G4QGSMFragmentation & G4QGSMFragmentation::operator=(const G4QGSMFragmentation &) |
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| 63 | { |
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| 64 | throw G4HadronicException(__FILE__, __LINE__, "G4QGSMFragmentation::operator= meant to not be accessable"); |
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| 65 | return *this; |
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| 66 | } |
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| 67 | |
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| 68 | int G4QGSMFragmentation::operator==(const G4QGSMFragmentation &right) const |
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| 69 | { |
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| 70 | return !memcmp(this, &right, sizeof(G4QGSMFragmentation)); |
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| 71 | } |
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| 72 | |
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| 73 | int G4QGSMFragmentation::operator!=(const G4QGSMFragmentation &right) const |
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| 74 | { |
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| 75 | return memcmp(this, &right, sizeof(G4QGSMFragmentation)); |
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| 76 | } |
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| 77 | |
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| 78 | //**************************************************************************************** |
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| 79 | //---------------------------------------------------------------------------------------------------------- |
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| 80 | |
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| 81 | G4KineticTrackVector* G4QGSMFragmentation::FragmentString(const G4ExcitedString& theString) |
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| 82 | { |
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| 83 | // Can no longer modify Parameters for Fragmentation. |
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| 84 | PastInitPhase=true; |
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| 85 | |
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| 86 | // check if string has enough mass to fragment... |
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| 87 | G4KineticTrackVector * LeftVector=LightFragmentationTest(&theString); |
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| 88 | if ( LeftVector != 0 ) return LeftVector; |
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| 89 | |
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| 90 | LeftVector = new G4KineticTrackVector; |
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| 91 | G4KineticTrackVector * RightVector=new G4KineticTrackVector; |
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| 92 | |
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| 93 | // this should work but its only a semi deep copy. %GF G4ExcitedString theStringInCMS(theString); |
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| 94 | G4ExcitedString *theStringInCMS=CPExcited(theString); |
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| 95 | G4LorentzRotation toCms=theStringInCMS->TransformToAlignedCms(); |
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| 96 | |
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| 97 | G4bool success=false, inner_sucess=true; |
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| 98 | G4int attempt=0; |
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| 99 | while ( !success && attempt++ < StringLoopInterrupt ) |
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| 100 | { |
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| 101 | G4FragmentingString *currentString=new G4FragmentingString(*theStringInCMS); |
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| 102 | |
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| 103 | std::for_each(LeftVector->begin(), LeftVector->end(), DeleteKineticTrack()); |
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| 104 | LeftVector->clear(); |
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| 105 | std::for_each(RightVector->begin(), RightVector->end(), DeleteKineticTrack()); |
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| 106 | RightVector->clear(); |
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| 107 | |
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| 108 | inner_sucess=true; // set false on failure.. |
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| 109 | while (! StopFragmenting(currentString) ) |
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| 110 | { // Split current string into hadron + new string |
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| 111 | G4FragmentingString *newString=0; // used as output from SplitUp... |
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| 112 | G4KineticTrack * Hadron=Splitup(currentString,newString); |
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| 113 | if ( Hadron != 0 && IsFragmentable(newString)) |
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| 114 | { |
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| 115 | if ( currentString->GetDecayDirection() > 0 ) |
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| 116 | LeftVector->push_back(Hadron); |
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| 117 | else |
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| 118 | RightVector->push_back(Hadron); |
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| 119 | delete currentString; |
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| 120 | currentString=newString; |
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| 121 | } else { |
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| 122 | // abandon ... start from the beginning |
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| 123 | if (newString) delete newString; |
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| 124 | if (Hadron) delete Hadron; |
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| 125 | inner_sucess=false; |
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| 126 | break; |
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| 127 | } |
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| 128 | } |
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| 129 | // Split current string into 2 final Hadrons |
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| 130 | if ( inner_sucess && |
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| 131 | SplitLast(currentString,LeftVector, RightVector) ) |
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| 132 | { |
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| 133 | success=true; |
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| 134 | } |
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| 135 | delete currentString; |
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| 136 | } |
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| 137 | |
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| 138 | delete theStringInCMS; |
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| 139 | |
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| 140 | if ( ! success ) |
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| 141 | { |
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| 142 | std::for_each(LeftVector->begin(), LeftVector->end(), DeleteKineticTrack()); |
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| 143 | LeftVector->clear(); |
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| 144 | std::for_each(RightVector->begin(), RightVector->end(), DeleteKineticTrack()); |
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| 145 | delete RightVector; |
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| 146 | return LeftVector; |
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| 147 | } |
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| 148 | |
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| 149 | // Join Left- and RightVector into LeftVector in correct order. |
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| 150 | while(!RightVector->empty()) |
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| 151 | { |
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| 152 | LeftVector->push_back(RightVector->back()); |
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| 153 | RightVector->erase(RightVector->end()-1); |
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| 154 | } |
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| 155 | delete RightVector; |
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| 156 | |
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| 157 | CalculateHadronTimePosition(theString.Get4Momentum().mag(), LeftVector); |
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| 158 | |
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| 159 | G4LorentzRotation toObserverFrame(toCms.inverse()); |
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| 160 | |
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| 161 | for(size_t C1 = 0; C1 < LeftVector->size(); C1++) |
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| 162 | { |
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| 163 | G4KineticTrack* Hadron = LeftVector->operator[](C1); |
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| 164 | G4LorentzVector Momentum = Hadron->Get4Momentum(); |
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| 165 | Momentum = toObserverFrame*Momentum; |
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| 166 | Hadron->Set4Momentum(Momentum); |
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| 167 | G4LorentzVector Coordinate(Hadron->GetPosition(), Hadron->GetFormationTime()); |
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| 168 | Momentum = toObserverFrame*Coordinate; |
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| 169 | Hadron->SetFormationTime(Momentum.e()); |
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| 170 | G4ThreeVector aPosition(Momentum.vect()); |
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| 171 | Hadron->SetPosition(theString.GetPosition()+aPosition); |
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| 172 | } |
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| 173 | return LeftVector; |
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| 174 | |
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| 175 | |
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| 176 | |
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| 177 | } |
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| 178 | |
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| 179 | //---------------------------------------------------------------------------------------------------------- |
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| 180 | |
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| 181 | G4double G4QGSMFragmentation::GetLightConeZ(G4double zmin, G4double zmax, G4int PartonEncoding, G4ParticleDefinition* , G4double , G4double ) |
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| 182 | { |
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| 183 | G4double z; |
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| 184 | G4double theA(0), d1, d2, yf; |
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| 185 | G4int absCode = std::abs( PartonEncoding ); |
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| 186 | if (absCode < 10) |
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| 187 | { |
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| 188 | if(absCode == 1 || absCode == 2) theA = arho; |
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| 189 | else if(absCode == 3) theA = aphi; |
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| 190 | else throw G4HadronicException(__FILE__, __LINE__, "Unknown PDGencoding in G4QGSMFragmentation::G4LightConeZ"); |
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| 191 | |
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| 192 | do |
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| 193 | { |
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| 194 | z = zmin + G4UniformRand() * (zmax - zmin); |
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| 195 | d1 = (1. - z); |
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| 196 | d2 = (alft - theA); |
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| 197 | yf = std::pow(d1, d2); |
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| 198 | } |
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| 199 | while (G4UniformRand() > yf); |
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| 200 | } |
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| 201 | else |
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| 202 | { |
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| 203 | if(absCode == 1103 || absCode == 2101 || |
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| 204 | absCode == 2203 || absCode == 2103) |
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| 205 | { |
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| 206 | d2 = (alft - (2.*an - arho)); |
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| 207 | } |
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| 208 | else if(absCode == 3101 || absCode == 3103 || |
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| 209 | absCode == 3201 || absCode == 3203) |
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| 210 | { |
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| 211 | d2 = (alft - (2.*ala - arho)); |
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| 212 | } |
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| 213 | else |
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| 214 | { |
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| 215 | d2 = (alft - (2.*aksi - arho)); |
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| 216 | } |
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| 217 | |
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| 218 | do |
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| 219 | { |
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| 220 | z = zmin + G4UniformRand() * (zmax - zmin); |
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| 221 | d1 = (1. - z); |
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| 222 | yf = std::pow(d1, d2); |
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| 223 | } |
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| 224 | while (G4UniformRand() > yf); |
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| 225 | } |
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| 226 | return z; |
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| 227 | } |
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| 228 | //----------------------------------------------------------------------------------------- |
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| 229 | |
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| 230 | G4LorentzVector * G4QGSMFragmentation::SplitEandP(G4ParticleDefinition * pHadron, |
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| 231 | G4FragmentingString * string) |
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| 232 | { |
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| 233 | G4double HadronMass = pHadron->GetPDGMass(); |
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| 234 | |
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| 235 | // calculate and assign hadron transverse momentum component HadronPx andHadronPy |
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| 236 | G4ThreeVector thePt; |
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| 237 | thePt=SampleQuarkPt(); |
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| 238 | G4ThreeVector HadronPt = thePt +string->DecayPt(); |
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| 239 | HadronPt.setZ(0); |
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| 240 | //... sample z to define hadron longitudinal momentum and energy |
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| 241 | //... but first check the available phase space |
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| 242 | G4double DecayQuarkMass2 = sqr(string->GetDecayParton()->GetPDGMass()); |
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| 243 | G4double HadronMass2T = sqr(HadronMass) + HadronPt.mag2(); |
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| 244 | if (DecayQuarkMass2 + HadronMass2T >= SmoothParam*(string->Mass2()) ) |
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| 245 | return 0; // have to start all over! |
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| 246 | |
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| 247 | //... then compute allowed z region z_min <= z <= z_max |
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| 248 | |
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| 249 | G4double zMin = HadronMass2T/(string->Mass2()); |
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| 250 | G4double zMax = 1. - DecayQuarkMass2/(string->Mass2()); |
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| 251 | if (zMin >= zMax) return 0; // have to start all over! |
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| 252 | |
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| 253 | G4double z = GetLightConeZ(zMin, zMax, |
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| 254 | string->GetDecayParton()->GetPDGEncoding(), pHadron, |
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| 255 | HadronPt.x(), HadronPt.y()); |
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| 256 | |
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| 257 | //... now compute hadron longitudinal momentum and energy |
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| 258 | // longitudinal hadron momentum component HadronPz |
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| 259 | |
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| 260 | HadronPt.setZ(0.5* string->GetDecayDirection() * |
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| 261 | (z * string->LightConeDecay() - |
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| 262 | HadronMass2T/(z * string->LightConeDecay()))); |
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| 263 | G4double HadronE = 0.5* (z * string->LightConeDecay() + |
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| 264 | HadronMass2T/(z * string->LightConeDecay())); |
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| 265 | |
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| 266 | G4LorentzVector * a4Momentum= new G4LorentzVector(HadronPt,HadronE); |
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| 267 | |
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| 268 | return a4Momentum; |
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| 269 | } |
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| 270 | |
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| 271 | |
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| 272 | //----------------------------------------------------------------------------------------- |
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| 273 | |
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| 274 | G4bool G4QGSMFragmentation::SplitLast(G4FragmentingString * string, |
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| 275 | G4KineticTrackVector * LeftVector, |
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| 276 | G4KineticTrackVector * RightVector) |
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| 277 | { |
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| 278 | //... perform last cluster decay |
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| 279 | G4ThreeVector ClusterVel =string->Get4Momentum().boostVector(); |
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| 280 | G4double ResidualMass =string->Mass(); |
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| 281 | G4double ClusterMassCut = ClusterMass; |
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| 282 | G4int cClusterInterrupt = 0; |
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| 283 | G4ParticleDefinition * LeftHadron, * RightHadron; |
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| 284 | do |
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| 285 | { |
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| 286 | if (cClusterInterrupt++ >= ClusterLoopInterrupt) |
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| 287 | { |
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| 288 | return false; |
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| 289 | } |
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| 290 | G4ParticleDefinition * quark = NULL; |
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| 291 | string->SetLeftPartonStable(); // to query quark contents.. |
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| 292 | if (string->DecayIsQuark() && string->StableIsQuark() ) |
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| 293 | { |
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| 294 | //... there are quarks on cluster ends |
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| 295 | LeftHadron= QuarkSplitup(string->GetLeftParton(), quark); |
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| 296 | } else { |
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| 297 | //... there is a Diquark on cluster ends |
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| 298 | G4int IsParticle; |
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| 299 | if ( string->StableIsQuark() ) { |
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| 300 | IsParticle=(string->GetLeftParton()->GetPDGEncoding()>0) ? -1 : +1; |
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| 301 | } else { |
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| 302 | IsParticle=(string->GetLeftParton()->GetPDGEncoding()>0) ? +1 : -1; |
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| 303 | } |
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| 304 | pDefPair QuarkPair = CreatePartonPair(IsParticle,false); // no diquarks wanted |
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| 305 | quark = QuarkPair.second; |
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| 306 | LeftHadron=hadronizer->Build(QuarkPair.first, string->GetLeftParton()); |
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| 307 | } |
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| 308 | RightHadron = hadronizer->Build(string->GetRightParton(), quark); |
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| 309 | |
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| 310 | //... repeat procedure, if mass of cluster is too low to produce hadrons |
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| 311 | //... ClusterMassCut = 0.15*GeV model parameter |
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| 312 | if ( quark->GetParticleSubType()== "quark" ) {ClusterMassCut = 0.;} |
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| 313 | else {ClusterMassCut = ClusterMass;} |
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| 314 | } |
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| 315 | while (ResidualMass <= LeftHadron->GetPDGMass() + RightHadron->GetPDGMass() + ClusterMassCut); |
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| 316 | |
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| 317 | //... compute hadron momenta and energies |
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| 318 | G4LorentzVector LeftMom, RightMom; |
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| 319 | G4ThreeVector Pos; |
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| 320 | Sample4Momentum(&LeftMom, LeftHadron->GetPDGMass(), &RightMom, RightHadron->GetPDGMass(), ResidualMass); |
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| 321 | LeftMom.boost(ClusterVel); |
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| 322 | RightMom.boost(ClusterVel); |
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| 323 | LeftVector->push_back(new G4KineticTrack(LeftHadron, 0, Pos, LeftMom)); |
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| 324 | RightVector->push_back(new G4KineticTrack(RightHadron, 0, Pos, RightMom)); |
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| 325 | |
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| 326 | return true; |
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| 327 | |
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| 328 | } |
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| 329 | |
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| 330 | //---------------------------------------------------------------------------------------------------------- |
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| 331 | |
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| 332 | G4bool G4QGSMFragmentation::IsFragmentable(const G4FragmentingString * const string) |
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| 333 | { |
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| 334 | return sqr(FragmentationMass(string)+MassCut) < |
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| 335 | string->Mass2(); |
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| 336 | } |
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| 337 | |
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| 338 | //---------------------------------------------------------------------------------------------------------- |
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| 339 | |
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| 340 | G4bool G4QGSMFragmentation::StopFragmenting(const G4FragmentingString * const string) |
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| 341 | { |
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| 342 | return |
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| 343 | sqr(FragmentationMass(string,&G4HadronBuilder::BuildHighSpin)+MassCut) > |
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| 344 | string->Get4Momentum().mag2(); |
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| 345 | } |
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| 346 | |
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| 347 | //---------------------------------------------------------------------------------------------------------- |
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| 348 | |
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| 349 | //---------------------------------------------------------------------------------------------------------- |
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| 350 | |
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| 351 | void G4QGSMFragmentation::Sample4Momentum(G4LorentzVector* Mom, G4double Mass, G4LorentzVector* AntiMom, G4double AntiMass, G4double InitialMass) |
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| 352 | { |
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| 353 | G4double r_val = sqr(InitialMass*InitialMass - Mass*Mass - AntiMass*AntiMass) - sqr(2.*Mass*AntiMass); |
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| 354 | G4double Pabs = (r_val > 0.)? std::sqrt(r_val)/(2.*InitialMass) : 0; |
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| 355 | |
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| 356 | //... sample unit vector |
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| 357 | G4double pz = 1. - 2.*G4UniformRand(); |
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| 358 | G4double st = std::sqrt(1. - pz * pz)*Pabs; |
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| 359 | G4double phi = 2.*pi*G4UniformRand(); |
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| 360 | G4double px = st*std::cos(phi); |
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| 361 | G4double py = st*std::sin(phi); |
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| 362 | pz *= Pabs; |
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| 363 | |
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| 364 | Mom->setPx(px); Mom->setPy(py); Mom->setPz(pz); |
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| 365 | Mom->setE(std::sqrt(Pabs*Pabs + Mass*Mass)); |
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| 366 | |
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| 367 | AntiMom->setPx(-px); AntiMom->setPy(-py); AntiMom->setPz(-pz); |
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| 368 | AntiMom->setE (std::sqrt(Pabs*Pabs + AntiMass*AntiMass)); |
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| 369 | } |
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| 370 | |
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| 371 | |
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| 372 | //********************************************************************************************* |
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