Geant4 11.1.1
Toolkit for the simulation of the passage of particles through matter
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Classes | Public Member Functions | List of all members
G4FTFAnnihilation Class Reference

#include <G4FTFAnnihilation.hh>

Public Member Functions

 G4FTFAnnihilation ()
 
virtual ~G4FTFAnnihilation ()
 
virtual G4bool Annihilate (G4VSplitableHadron *aPartner, G4VSplitableHadron *bPartner, G4VSplitableHadron *&AdditionalString, G4FTFParameters *theParameters) const
 

Detailed Description

Definition at line 49 of file G4FTFAnnihilation.hh.

Constructor & Destructor Documentation

◆ G4FTFAnnihilation()

G4FTFAnnihilation::G4FTFAnnihilation ( )

Definition at line 76 of file G4FTFAnnihilation.cc.

76{}

◆ ~G4FTFAnnihilation()

G4FTFAnnihilation::~G4FTFAnnihilation ( )
virtual

Definition at line 81 of file G4FTFAnnihilation.cc.

81{}

Member Function Documentation

◆ Annihilate()

G4bool G4FTFAnnihilation::Annihilate ( G4VSplitableHadron *  aPartner,
G4VSplitableHadron *  bPartner,
G4VSplitableHadron *&  AdditionalString,
G4FTFParameters *  theParameters 
) const
virtual

Definition at line 86 of file G4FTFAnnihilation.cc.

89 {
90
91 #ifdef debugFTFannih
92 G4cout << "---------------------------- Annihilation----------------" << G4endl;
93 #endif
94
95 CommonVariables common;
96
97 // Projectile parameters
98 common.Pprojectile = projectile->Get4Momentum();
99 G4int ProjectilePDGcode = projectile->GetDefinition()->GetPDGEncoding();
100 if ( ProjectilePDGcode > 0 ) {
101 target->SetStatus( 3 );
102 return false;
103 }
104 G4double M0projectile2 = common.Pprojectile.mag2();
105
106 // Target parameters
107 G4int TargetPDGcode = target->GetDefinition()->GetPDGEncoding();
108 common.Ptarget = target->Get4Momentum();
109 G4double M0target2 = common.Ptarget.mag2();
110
111 #ifdef debugFTFannih
112 G4cout << "PDG codes " << ProjectilePDGcode << " " << TargetPDGcode << G4endl
113 << "Pprojec " << common.Pprojectile << " " << common.Pprojectile.mag() << G4endl
114 << "Ptarget " << common.Ptarget << " " << common.Ptarget.mag() << G4endl
115 << "M0 proj target " << std::sqrt( M0projectile2 )
116 << " " << std::sqrt( M0target2 ) << G4endl;
117 #endif
118
119 // Kinematical properties of the interactions
120 G4LorentzVector Psum = common.Pprojectile + common.Ptarget; // 4-momentum in CMS
121 common.S = Psum.mag2();
122 common.SqrtS = std::sqrt( common.S );
123 #ifdef debugFTFannih
124 G4cout << "Psum SqrtS S " << Psum << " " << common.SqrtS << " " << common.S << G4endl;
125 #endif
126
127 // Transform momenta to cms and then rotate parallel to z axis
128 G4LorentzRotation toCms( -1*Psum.boostVector() );
129 G4LorentzVector Ptmp( toCms*common.Pprojectile );
130 toCms.rotateZ( -1*Ptmp.phi() );
131 toCms.rotateY( -1*Ptmp.theta() );
132 common.toLab = toCms.inverse();
133
134 if ( G4UniformRand() <= G4Pow::GetInstance()->powA( 1880.0/common.SqrtS, 4.0 ) ) {
135 common.RotateStrings = true;
136 common.RandomRotation.rotateZ( 2.0*pi*G4UniformRand() );
137 common.RandomRotation.rotateY( std::acos( 2.0*G4UniformRand() - 1.0 ) );
138 common.RandomRotation.rotateZ( 2.0*pi*G4UniformRand() );
139 }
140
141 G4double MesonProdThreshold = projectile->GetDefinition()->GetPDGMass() +
142 target->GetDefinition()->GetPDGMass() +
143 ( 2.0*140.0 + 16.0 )*MeV; // 2 Mpi + DeltaE
144 G4double Prel2 = sqr(common.S) + sqr(M0projectile2) + sqr(M0target2)
145 - 2.0*( common.S*(M0projectile2 + M0target2) + M0projectile2*M0target2 );
146 Prel2 /= common.S;
147 G4double X_a = 0.0, X_b = 0.0, X_c = 0.0, X_d = 0.0;
148 if ( Prel2 <= 0.0 ) {
149 // Annihilation at rest! Values are copied from Parameters
150 X_a = 625.1; // mb // 3-shirt diagram
151 X_b = 0.0; // mb // anti-quark-quark annihilation
152 X_c = 49.989; // mb // 2 Q-Qbar string creation
153 X_d = 6.614; // mb // One Q-Qbar string
154 #ifdef debugFTFannih
155 G4cout << "Annih at Rest X a b c d " << X_a << " " << X_b << " " << X_c << " " << X_d
156 << G4endl;
157 #endif
158 } else { // Annihilation in flight!
159 G4double FlowF = 1.0 / std::sqrt( Prel2 )*GeV;
160 // Process cross sections
161 X_a = 25.0*FlowF; // mb 3-shirt diagram
162 if ( common.SqrtS < MesonProdThreshold ) {
163 X_b = 3.13 + 140.0*G4Pow::GetInstance()->powA( ( MesonProdThreshold - common.SqrtS )/GeV, 2.5 );
164 } else {
165 X_b = 6.8*GeV / common.SqrtS; // mb anti-quark-quark annihilation
166 }
167 if ( projectile->GetDefinition()->GetPDGMass() + target->GetDefinition()->GetPDGMass()
168 > common.SqrtS ) {
169 X_b = 0.0;
170 }
171 // This can be in an interaction of low energy anti-baryon with off-shell nuclear nucleon
172 X_c = 2.0 * FlowF * sqr( projectile->GetDefinition()->GetPDGMass() +
173 target->GetDefinition()->GetPDGMass() ) / common.S; // mb re-arrangement of
174 // 2 quarks and 2 anti-quarks
175 X_d = 23.3*GeV*GeV / common.S; // mb anti-quark-quark string creation
176 #ifdef debugFTFannih
177 G4cout << "Annih in Flight X a b c d " << X_a << " " << X_b << " " << X_c << " " << X_d
178 << G4endl << "SqrtS MesonProdThreshold " << common.SqrtS << " " << MesonProdThreshold
179 << G4endl;
180 #endif
181 }
182
183 G4bool isUnknown = false;
184 if ( TargetPDGcode == 2212 || TargetPDGcode == 2214 ) { // Target proton or Delta+
185 if ( ProjectilePDGcode == -2212 || ProjectilePDGcode == -2214 ) { // anti_proton or anti_Delta+
186 X_b *= 5.0; X_c *= 5.0; X_d *= 6.0; // Pbar P
187 } else if ( ProjectilePDGcode == -2112 || ProjectilePDGcode == -2114 ) { // anti_neutron or anti_Delta0
188 X_b *= 4.0; X_c *= 4.0; X_d *= 4.0; // NeutrBar P
189 } else if ( ProjectilePDGcode == -3122 ) { // anti_Lambda (no anti_Lambda* in PDG)
190 X_b *= 3.0; X_c *= 3.0; X_d *= 2.0; // LambdaBar P
191 } else if ( ProjectilePDGcode == -3112 ) { // anti_Sigma- (no anti_Sigma*- in G4)
192 X_b *= 2.0; X_c *= 2.0; X_d *= 0.0; // Sigma-Bar P
193 } else if ( ProjectilePDGcode == -3212 ) { // anti_Sigma0 (no anti_Sigma*0 in G4)
194 X_b *= 3.0; X_c *= 3.0; X_d *= 2.0; // Sigma0Bar P
195 } else if ( ProjectilePDGcode == -3222 ) { // anti_Sigma+ (no anti_Sigma*+ in G4)
196 X_b *= 4.0; X_c *= 4.0; X_d *= 2.0; // Sigma+Bar P
197 } else if ( ProjectilePDGcode == -3312 ) { // anti_Xi- (no anti_Xi*- in G4)
198 X_b *= 1.0; X_c *= 1.0; X_d *= 0.0; // Xi-Bar P
199 } else if ( ProjectilePDGcode == -3322 ) { // anti_Xi0 (no anti_Xi*0 in G4)
200 X_b *= 2.0; X_c *= 2.0; X_d *= 0.0; // Xi0Bar P
201 } else if ( ProjectilePDGcode == -3334 ) { // anti_Omega- (no anti_Omega*- in PDG)
202 X_b *= 0.0; X_c *= 0.0; X_d *= 0.0; // Omega-Bar P
203 } else {
204 isUnknown = true;
205 }
206 } else if ( TargetPDGcode == 2112 || TargetPDGcode == 2114 ) { // Target neutron or Delta0
207 if ( ProjectilePDGcode == -2212 || ProjectilePDGcode == -2214 ) { // anti_proton or anti_Delta+
208 X_b *= 4.0; X_c *= 4.0; X_d *= 4.0; // Pbar N
209 } else if ( ProjectilePDGcode == -2112 || ProjectilePDGcode == -2114 ) { // anti_neutron or anti_Delta0
210 X_b *= 5.0; X_c *= 5.0; X_d *= 6.0; // NeutrBar N
211 } else if ( ProjectilePDGcode == -3122 ) { // anti_Lambda (no anti_Lambda* in PDG)
212 X_b *= 3.0; X_c *= 3.0; X_d *= 2.0; // LambdaBar N
213 } else if ( ProjectilePDGcode == -3112 ) { // anti_Sigma- (no anti_Sigma*- in G4)
214 X_b *= 4.0; X_c *= 4.0; X_d *= 2.0; // Sigma-Bar N
215 } else if ( ProjectilePDGcode == -3212 ) { // anti_Sigma0 (no anti_Sigma*0 in G4)
216 X_b *= 3.0; X_c *= 3.0; X_d *= 2.0; // Sigma0Bar N
217 } else if ( ProjectilePDGcode == -3222 ) { // anti_Sigma+ (no anti_Sigma*+ in G4)
218 X_b *= 2.0; X_c *= 2.0; X_d *= 0.0; // Sigma+Bar N
219 } else if ( ProjectilePDGcode == -3312 ) { // anti_Xi- (no anti_Xi*- in G4)
220 X_b *= 2.0; X_c *= 2.0; X_d *= 0.0; // Xi-Bar N
221 } else if ( ProjectilePDGcode == -3322 ) { // anti_Xi0 (no anti_Xi*0 in G4)
222 X_b *= 1.0; X_c *= 1.0; X_d *= 0.0; // Xi0Bar N
223 } else if ( ProjectilePDGcode == -3334 ) { // anti_Omega- (no anti_Omega*- in PDG)
224 X_b *= 0.0; X_c *= 0.0; X_d *= 0.0; // Omega-Bar N
225 } else {
226 isUnknown = true;
227 }
228 } else {
229 isUnknown = true;
230 }
231 if ( isUnknown ) {
232 G4cout << "Unknown anti-baryon for FTF annihilation: PDGcodes - "
233 << ProjectilePDGcode << " " << TargetPDGcode << G4endl;
234 }
235
236 #ifdef debugFTFannih
237 G4cout << "Annih Actual X a b c d " << X_a << " " << X_b << " " << X_c << " " << X_d << G4endl;
238 #endif
239
240 G4double Xannihilation = X_a + X_b + X_c + X_d;
241
242 // Projectile unpacking
243 UnpackBaryon( ProjectilePDGcode, common.AQ[0], common.AQ[1], common.AQ[2] );
244
245 // Target unpacking
246 UnpackBaryon( TargetPDGcode, common.Q[0], common.Q[1], common.Q[2] );
247
248 G4double Ksi = G4UniformRand();
249
250 if ( Ksi < X_a / Xannihilation ) {
251 return Create3QuarkAntiQuarkStrings( projectile, target, AdditionalString, theParameters, common );
252 }
253
254 G4int resultCode = 99;
255 if ( Ksi < (X_a + X_b) / Xannihilation ) {
256 resultCode = Create1DiquarkAntiDiquarkString( projectile, target, common );
257 if ( resultCode == 0 ) {
258 return true;
259 } else if ( resultCode == 99 ) {
260 return false;
261 }
262 }
263
264 if ( Ksi < ( X_a + X_b + X_c ) / Xannihilation ) {
265 resultCode = Create2QuarkAntiQuarkStrings( projectile, target, theParameters, common );
266 if ( resultCode == 0 ) {
267 return true;
268 } else if ( resultCode == 99 ) {
269 return false;
270 }
271 }
272
273 if ( Ksi < ( X_a + X_b + X_c + X_d ) / Xannihilation ) {
274 return Create1QuarkAntiQuarkString( projectile, target, theParameters, common );
275 }
276
277 return true;
278}
G4double
double G4double
Definition: G4Types.hh:83
G4bool
bool G4bool
Definition: G4Types.hh:86
G4int
int G4int
Definition: G4Types.hh:85
G4endl
#define G4endl
Definition: G4ios.hh:57
G4cout
G4GLOB_DLL std::ostream G4cout
G4UniformRand
#define G4UniformRand()
Definition: Randomize.hh:52
CLHEP::HepLorentzVector::boostVector
Hep3Vector boostVector() const
Definition: LorentzVector.cc:173
G4Pow::GetInstance
static G4Pow * GetInstance()
Definition: G4Pow.cc:41
G4Pow::powA
G4double powA(G4double A, G4double y) const
Definition: G4Pow.hh:230
sqr
T sqr(const T &x)
Definition: templates.hh:128
The documentation for this class was generated from the following files: