[968] | 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: G4ElasticHNScattering.cc,v 1.3 2008/05/19 12:56:36 vuzhinsk Exp $ |
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| 28 | // ------------------------------------------------------------ |
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| 29 | // GEANT 4 class implemetation file |
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| 30 | // |
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| 31 | // ---------------- G4ElasticHNScattering -------------- |
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| 32 | // by V. Uzhinsky, March 2008. |
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| 33 | // elastic scattering used by Fritiof model |
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| 34 | // Take a projectile and a target |
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| 35 | // scatter the projectile and target |
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| 36 | // --------------------------------------------------------------------- |
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| 37 | |
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| 38 | |
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| 39 | #include "globals.hh" |
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| 40 | #include "Randomize.hh" |
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| 41 | |
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| 42 | #include "G4ElasticHNScattering.hh" |
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| 43 | #include "G4LorentzRotation.hh" |
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| 44 | #include "G4ThreeVector.hh" |
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| 45 | #include "G4ParticleDefinition.hh" |
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| 46 | #include "G4VSplitableHadron.hh" |
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| 47 | #include "G4ExcitedString.hh" |
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| 48 | #include "G4FTFParameters.hh" // Uzhi 29.03.08 |
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| 49 | //#include "G4ios.hh" |
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| 50 | |
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| 51 | G4ElasticHNScattering::G4ElasticHNScattering() |
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| 52 | { |
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| 53 | } |
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| 54 | |
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| 55 | G4bool G4ElasticHNScattering:: |
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| 56 | ElasticScattering (G4VSplitableHadron *projectile, |
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| 57 | G4VSplitableHadron *target, |
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| 58 | G4FTFParameters *theParameters) const |
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| 59 | { |
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| 60 | //G4cout<<"G4ElasticHNScattering::ElasticScattering"<<G4endl; |
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| 61 | |
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| 62 | G4LorentzVector Pprojectile=projectile->Get4Momentum(); |
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| 63 | |
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| 64 | // -------------------- Projectile parameters ----------------------------------- |
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| 65 | G4bool PutOnMassShell=0; |
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| 66 | |
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| 67 | G4double M0projectile = Pprojectile.mag(); |
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| 68 | |
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| 69 | if(M0projectile < projectile->GetDefinition()->GetPDGMass()) |
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| 70 | { |
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| 71 | PutOnMassShell=1; |
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| 72 | M0projectile=projectile->GetDefinition()->GetPDGMass(); |
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| 73 | } |
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| 74 | |
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| 75 | G4double Mprojectile2 = M0projectile * M0projectile; |
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| 76 | |
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| 77 | // G4double AveragePt2=theParameters->GetSlope(); // Uzhi ??? |
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| 78 | // AveragePt2 = AveragePt2 * GeV*GeV; |
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| 79 | |
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| 80 | G4double AveragePt2=theParameters->GetAvaragePt2ofElasticScattering(); |
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| 81 | |
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| 82 | // -------------------- Target parameters ---------------------------------------------- |
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| 83 | G4LorentzVector Ptarget=target->Get4Momentum(); |
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| 84 | |
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| 85 | G4double M0target = Ptarget.mag(); |
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| 86 | //G4cout<<" Mp Mt Pt2 "<<M0projectile<<" "<<M0target<<" "<<AveragePt2/GeV/GeV<<G4endl; |
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| 87 | |
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| 88 | if(M0target < target->GetDefinition()->GetPDGMass()) |
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| 89 | { |
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| 90 | PutOnMassShell=1; |
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| 91 | M0target=target->GetDefinition()->GetPDGMass(); |
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| 92 | } |
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| 93 | |
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| 94 | G4double Mtarget2 = M0target * M0target; //Ptarget.mag2(); |
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| 95 | // for AA-inter. |
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| 96 | // Transform momenta to cms and then rotate parallel to z axis; |
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| 97 | |
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| 98 | G4LorentzVector Psum; |
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| 99 | Psum=Pprojectile+Ptarget; |
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| 100 | |
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| 101 | G4LorentzRotation toCms(-1*Psum.boostVector()); |
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| 102 | |
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| 103 | G4LorentzVector Ptmp=toCms*Pprojectile; |
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| 104 | |
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| 105 | if ( Ptmp.pz() <= 0. ) // Uzhi ??? |
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| 106 | { |
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| 107 | // "String" moving backwards in CMS, abort collision !! |
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| 108 | //G4cout << " abort Collision!! " << G4endl; |
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| 109 | return false; |
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| 110 | } |
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| 111 | |
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| 112 | toCms.rotateZ(-1*Ptmp.phi()); |
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| 113 | toCms.rotateY(-1*Ptmp.theta()); |
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| 114 | |
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| 115 | G4LorentzRotation toLab(toCms.inverse()); |
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| 116 | |
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| 117 | Pprojectile.transform(toCms); |
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| 118 | Ptarget.transform(toCms); |
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| 119 | |
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| 120 | // ---------------------- Sampling of transfered Pt ------------------------ |
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| 121 | G4double Pt2; |
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| 122 | G4double ProjMassT2, ProjMassT; |
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| 123 | G4double TargMassT2, TargMassT; |
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| 124 | G4double PZcms2, PZcms; |
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| 125 | |
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| 126 | G4double S=Psum.mag2(); |
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| 127 | // G4double SqrtS=std::sqrt(S); |
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| 128 | |
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| 129 | PZcms2=(S*S+Mprojectile2*Mprojectile2+Mtarget2*Mtarget2- |
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| 130 | 2*S*Mprojectile2-2*S*Mtarget2-2*Mprojectile2*Mtarget2)/4./S; |
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| 131 | if(PZcms2 < 0) |
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| 132 | {return false;} // It can be in an interaction with off-shell nuclear nucleon |
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| 133 | |
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| 134 | PZcms = std::sqrt(PZcms2); |
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| 135 | |
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| 136 | if(PutOnMassShell) |
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| 137 | { |
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| 138 | if(Pprojectile.z() > 0.) |
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| 139 | { |
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| 140 | Pprojectile.setPz( PZcms); |
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| 141 | Ptarget.setPz( -PZcms); |
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| 142 | } |
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| 143 | else |
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| 144 | { |
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| 145 | Pprojectile.setPz(-PZcms); |
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| 146 | Ptarget.setPz( PZcms); |
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| 147 | }; |
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| 148 | |
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| 149 | Pprojectile.setE(std::sqrt(Mprojectile2+ |
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| 150 | Pprojectile.x()*Pprojectile.x()+ |
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| 151 | Pprojectile.y()*Pprojectile.y()+ |
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| 152 | PZcms2)); |
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| 153 | Ptarget.setE(std::sqrt( Mtarget2 + |
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| 154 | Ptarget.x()*Ptarget.x()+ |
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| 155 | Ptarget.y()*Ptarget.y()+ |
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| 156 | PZcms2)); |
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| 157 | } |
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| 158 | |
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| 159 | G4double maxPtSquare = PZcms2; |
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| 160 | G4LorentzVector Qmomentum; |
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| 161 | |
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| 162 | Qmomentum=G4LorentzVector(GaussianPt(AveragePt2,maxPtSquare),0); |
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| 163 | |
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| 164 | Pt2=G4ThreeVector(Qmomentum.vect()).mag2(); |
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| 165 | //G4cout<<"Pt2 GeV^2 "<<(Pt2)/GeV/GeV<<G4endl; |
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| 166 | |
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| 167 | ProjMassT2=Mprojectile2+Pt2; |
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| 168 | ProjMassT =std::sqrt(ProjMassT2); |
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| 169 | |
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| 170 | TargMassT2=Mtarget2+Pt2; |
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| 171 | TargMassT =std::sqrt(TargMassT2); |
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| 172 | |
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| 173 | PZcms2=(S*S+ProjMassT2*ProjMassT2+ |
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| 174 | TargMassT2*TargMassT2- |
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| 175 | 2.*S*ProjMassT2-2.*S*TargMassT2- |
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| 176 | 2.*ProjMassT2*TargMassT2)/4./S; |
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| 177 | if(PZcms2 < 0 ) {PZcms2=0;}; |
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| 178 | PZcms =std::sqrt(PZcms2); |
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| 179 | |
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| 180 | Pprojectile.setPz( PZcms); // Uzhi Proj can move backward |
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| 181 | Ptarget.setPz( -PZcms); // Uzhi Proj can move backward |
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| 182 | |
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| 183 | //G4cout << "Qplus / Qminus " << Qplus << " / " << Qminus<<G4endl; |
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| 184 | // G4cout << "pt2" << pt2 << G4endl; |
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| 185 | // G4cout << "Qmomentum " << Qmomentum << G4endl; |
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| 186 | // G4cout << " Masses (P/T) : " << (Pprojectile+Qmomentum).mag() << |
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| 187 | // " / " << (Ptarget-Qmomentum).mag() << G4endl; |
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| 188 | |
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| 189 | Pprojectile += Qmomentum; |
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| 190 | Ptarget -= Qmomentum; |
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| 191 | |
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| 192 | //G4cout << "Pprojectile with Q : " << Pprojectile << G4endl; |
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| 193 | //G4cout << "Ptarget with Q : " << Ptarget << G4endl; |
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| 194 | |
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| 195 | // G4cout << "Projectile back: " << toLab * Pprojectile << G4endl; |
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| 196 | // G4cout << "Target back: " << toLab * Ptarget << G4endl; |
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| 197 | |
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| 198 | // Transform back and update SplitableHadron Participant. |
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| 199 | Pprojectile.transform(toLab); |
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| 200 | Ptarget.transform(toLab); |
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| 201 | |
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| 202 | //G4cout << "Pprojectile with Q M: " << Pprojectile<<" "<< Pprojectile.mag() << G4endl; |
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| 203 | //G4cout << "Ptarget with Q M: " << Ptarget <<" "<< Ptarget.mag() << G4endl; |
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| 204 | |
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| 205 | //G4cout << "Target mass " << Ptarget.mag() << G4endl; |
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| 206 | |
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| 207 | //G4cout << "Projectile mass " << Pprojectile.mag() << G4endl; |
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| 208 | |
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| 209 | G4double ZcoordinateOfCurrentInteraction = target->GetPosition().z(); |
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| 210 | // It is assumed that nucleon z-coordinates are ordered on increasing ----------- |
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| 211 | |
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| 212 | G4double betta_z=projectile->Get4Momentum().pz()/projectile->Get4Momentum().e(); |
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| 213 | |
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| 214 | G4double ZcoordinateOfPreviousCollision=projectile->GetPosition().z(); |
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| 215 | if(projectile->GetSoftCollisionCount()==0) { |
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| 216 | projectile->SetTimeOfCreation(0.); |
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| 217 | target->SetTimeOfCreation(0.); |
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| 218 | ZcoordinateOfPreviousCollision=ZcoordinateOfCurrentInteraction; |
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| 219 | } |
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| 220 | |
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| 221 | G4ThreeVector thePosition(projectile->GetPosition().x(), |
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| 222 | projectile->GetPosition().y(), |
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| 223 | ZcoordinateOfCurrentInteraction); |
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| 224 | projectile->SetPosition(thePosition); |
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| 225 | |
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| 226 | G4double TimeOfPreviousCollision=projectile->GetTimeOfCreation(); |
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| 227 | G4double TimeOfCurrentCollision=TimeOfPreviousCollision+ |
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| 228 | (ZcoordinateOfCurrentInteraction-ZcoordinateOfPreviousCollision)/betta_z; |
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| 229 | |
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| 230 | projectile->SetTimeOfCreation(TimeOfCurrentCollision); |
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| 231 | target->SetTimeOfCreation(TimeOfCurrentCollision); |
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| 232 | |
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| 233 | projectile->Set4Momentum(Pprojectile); |
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| 234 | target->Set4Momentum(Ptarget); |
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| 235 | |
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| 236 | projectile->IncrementCollisionCount(1); |
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| 237 | target->IncrementCollisionCount(1); |
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| 238 | |
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| 239 | return true; |
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| 240 | } |
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| 241 | |
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| 242 | |
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| 243 | // --------- private methods ---------------------- |
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| 244 | |
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| 245 | G4ThreeVector G4ElasticHNScattering::GaussianPt(G4double AveragePt2, G4double maxPtSquare) const |
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| 246 | { // @@ this method is used in FTFModel as well. Should go somewhere common! |
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| 247 | |
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| 248 | G4double Pt2; |
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| 249 | Pt2 = -AveragePt2 * std::log(1. + G4UniformRand() * |
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| 250 | (std::exp(-maxPtSquare/AveragePt2)-1.)); |
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| 251 | |
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| 252 | G4double Pt=std::sqrt(Pt2); |
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| 253 | G4double phi=G4UniformRand() * twopi; |
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| 254 | |
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| 255 | return G4ThreeVector (Pt*std::cos(phi), Pt*std::sin(phi), 0.); |
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| 256 | } |
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| 257 | |
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| 258 | G4ElasticHNScattering::G4ElasticHNScattering(const G4ElasticHNScattering &) |
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| 259 | { |
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| 260 | throw G4HadronicException(__FILE__, __LINE__, "G4ElasticHNScattering copy contructor not meant to be called"); |
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| 261 | } |
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| 262 | |
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| 263 | |
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| 264 | G4ElasticHNScattering::~G4ElasticHNScattering() |
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| 265 | { |
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| 266 | } |
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| 267 | |
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| 268 | |
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| 269 | const G4ElasticHNScattering & G4ElasticHNScattering::operator=(const G4ElasticHNScattering &) |
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| 270 | { |
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| 271 | throw G4HadronicException(__FILE__, __LINE__, "G4ElasticHNScattering = operator meant to be called"); |
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| 272 | return *this; |
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| 273 | } |
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| 274 | |
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| 275 | |
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| 276 | int G4ElasticHNScattering::operator==(const G4ElasticHNScattering &) const |
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| 277 | { |
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| 278 | throw G4HadronicException(__FILE__, __LINE__, "G4ElasticHNScattering == operator meant to be called"); |
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| 279 | return false; |
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| 280 | } |
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| 281 | |
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| 282 | int G4ElasticHNScattering::operator!=(const G4ElasticHNScattering &) const |
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| 283 | { |
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| 284 | throw G4HadronicException(__FILE__, __LINE__, "G4ElasticHNScattering != operator meant to be called"); |
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| 285 | return true; |
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| 286 | } |
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