Several corrections. By A.Morsch
[u/mrichter/AliRoot.git] / EVGEN / AliGenPythia.cxx
CommitLineData
fe4da5cc 1#include "AliGenerator.h"
2#include "AliGenPythia.h"
3#include "TGeant3.h"
4#include "AliRun.h"
5#include "AliPythia.h"
6#include <TDirectory.h>
7#include <TFile.h>
8#include <TTree.h>
9#include <stdlib.h>
10#include <AliPythia.h>
11#include <TMCParticle.h>
12#include <GParticle.h>
13 ClassImp(AliGenPythia)
14
15AliGenPythia::AliGenPythia()
16 :AliGenerator()
17{
18}
19
20AliGenPythia::AliGenPythia(Int_t npart)
21 :AliGenerator(npart)
22{
23// default charm production at 5. 5 TeV
24// semimuonic decay
25// structure function GRVHO
26//
27 fXsection = 0.;
28 fParentSelect.Set(5);
29 fChildSelect.Set(5);
30 for (Int_t i=0; i<5; i++) fParentSelect[i]=fChildSelect[i]=0;
31 SetProcess();
32 SetStrucFunc();
33 ForceDecay();
34 SetPtHard();
35 SetEnergyCMS();
36}
37
38AliGenPythia::~AliGenPythia()
39{
40}
41
42void AliGenPythia::Init()
43{
44 SetMC(new AliPythia());
45 fPythia=(AliPythia*) fgMCEvGen;
46//
47 fParentWeight=1./Float_t(fNpart);
48//
49// Forward Paramters to the AliPythia object
50 fPythia->DefineParticles();
fe4da5cc 51 fPythia->SetCKIN(3,fPtHardMin);
52 fPythia->SetCKIN(4,fPtHardMax);
53 fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
5be1fe76 54 fPythia->ForceDecay(fForceDecay);
fe4da5cc 55 fPythia->LuList(0);
56 fPythia->PyStat(2);
57// Parent and Children Selection
58 switch (fProcess)
59 {
60 case charm:
61
62 fParentSelect[0]=411;
63 fParentSelect[1]=421;
64 fParentSelect[2]=431;
65 fParentSelect[3]=4122;
66 break;
67 case charm_unforced:
68
69 fParentSelect[0]=411;
70 fParentSelect[1]=421;
71 fParentSelect[2]=431;
72 fParentSelect[3]=4122;
73 break;
74 case beauty:
75 fParentSelect[0]=511;
76 fParentSelect[1]=521;
77 fParentSelect[2]=531;
78 fParentSelect[3]=5122;
79 break;
80 case beauty_unforced:
81 fParentSelect[0]=511;
82 fParentSelect[1]=521;
83 fParentSelect[2]=531;
84 fParentSelect[3]=5122;
85 break;
86 case jpsi_chi:
87 case jpsi:
88 fParentSelect[0]=443;
89 break;
5be1fe76 90 case mb:
91 break;
fe4da5cc 92 }
93
94 switch (fForceDecay)
95 {
96 case semielectronic:
97 case dielectron:
98 case b_jpsi_dielectron:
99 case b_psip_dielectron:
100 fChildSelect[0]=11;
101 break;
102 case semimuonic:
103 case dimuon:
104 case b_jpsi_dimuon:
105 case b_psip_dimuon:
5be1fe76 106 case pitomu:
107 case katomu:
fe4da5cc 108 fChildSelect[0]=13;
109 break;
110 }
111}
112
113void AliGenPythia::Generate()
114{
115 AliMC* pMC = AliMC::GetMC();
116
5be1fe76 117 Float_t polar[3] = {0,0,0};
118 Float_t origin[3]= {0,0,0};
119 Float_t origin_p[3]= {0,0,0};
120 Float_t origin0[3]= {0,0,0};
121 Float_t p[3], p_p[4], random[6];
122// converts from mm/c to s
123 const Float_t kconv=0.001/2.999792458e8;
fe4da5cc 124
125
126//
fe4da5cc 127 Int_t nt=0;
5be1fe76 128 Int_t nt_p=0;
fe4da5cc 129 Int_t jev=0;
130 Int_t j;
131
132 fTrials=0;
133 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
134 if(fVertexSmear==perEvent) {
135 pMC->Rndm(random,6);
136 for (j=0;j<3;j++) {
137 origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
138 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
139 fPythia->SetMSTP(151,0);
140 }
141 } else if (fVertexSmear==perTrack) {
142 fPythia->SetMSTP(151,0);
143 for (j=0;j<3;j++) {
144 fPythia->SetPARP(151+j, fOsigma[j]*10.);
145 }
146 }
fe4da5cc 147 while(1)
148 {
149 fPythia->PyEvnt();
150 fTrials++;
151 TObjArray* particles = fPythia->GetPrimaries() ;
152 Int_t np = particles->GetEntriesFast();
153 printf("\n **************************************************%d\n",np);
154 Int_t nc=0;
155 if (np == 0 ) continue;
5be1fe76 156 if (fProcess != mb) {
157 for (Int_t i = 0; i<np; i++) {
158 TMCParticle * iparticle = (TMCParticle *) particles->At(i);
159 Int_t kf = iparticle->GetKF();
160 fChildWeight=(fPythia->GetBraPart(kf))*fParentWeight;
fe4da5cc 161//
162// Parent
5be1fe76 163 if (ParentSelected(TMath::Abs(kf))) {
164 if (KinematicSelection(iparticle)) {
165 if (nc==0) {
166//
167// Store information concerning the hard scattering process
168//
169 Float_t mass_p = fPythia->GetPARI(13);
170 Float_t pt_p = fPythia->GetPARI(17);
171 Float_t y_p = fPythia->GetPARI(37);
172 Float_t xmt_p = sqrt(pt_p*pt_p+mass_p*mass_p);
173 Float_t ty = Float_t(TMath::TanH(y_p));
174 p_p[0] = pt_p;
175 p_p[1] = 0;
176 p_p[2] = xmt_p*ty/sqrt(1.-ty*ty);
177 p_p[3] = mass_p;
178 gAlice->SetTrack(0,-1,-1,
179 p_p,origin_p,polar,
180 0,"Hard Scat.",nt_p,fParentWeight);
181 gAlice->KeepTrack(nt_p);
182 }
183 nc++;
fe4da5cc 184//
185// store parent track information
5be1fe76 186 p[0]=iparticle->GetPx();
187 p[1]=iparticle->GetPy();
188 p[2]=iparticle->GetPz();
189 origin[0]=origin0[0]+iparticle->GetVx()/10;
190 origin[1]=origin0[1]+iparticle->GetVy()/10;
191 origin[2]=origin0[2]+iparticle->GetVz()/10;
fe4da5cc 192
5be1fe76 193 Int_t ifch=iparticle->GetFirstChild();
194 Int_t ilch=iparticle->GetLastChild();
195 if (ifch !=0 && ilch !=0) {
196 gAlice->SetTrack(0,nt_p,fPythia->GetGeantCode(kf),
197 p,origin,polar,
198 0,"Primary",nt,fParentWeight);
199 gAlice->KeepTrack(nt);
200 Int_t iparent = nt;
fe4da5cc 201//
202// Children
203
5be1fe76 204 for (Int_t j=ifch; j<=ilch; j++)
205 {
206 TMCParticle * ichild =
207 (TMCParticle *) particles->At(j-1);
208 Int_t kf = ichild->GetKF();
fe4da5cc 209//
210//
5be1fe76 211 if (ChildSelected(TMath::Abs(kf))) {
212 Int_t kg=fPythia->GetGeantCode(kf);
213 origin[0]=ichild->GetVx();
214 origin[1]=ichild->GetVy();
215 origin[2]=ichild->GetVz();
216 p[0]=ichild->GetPx();
217 p[1]=ichild->GetPy();
218 p[2]=ichild->GetPz();
219 Float_t tof=kconv*ichild->GetTime();
220 gAlice->SetTrack(fTrackIt, iparent, kg,
221 p,origin,polar,
222 tof,"Decay",nt,fChildWeight);
223 gAlice->KeepTrack(nt);
224 } // select child
225 } // child loop
226 }
227 } // kinematic selection
228 } // select particle
229 } // particle loop
230 } else {
231 for (Int_t i = 0; i<np; i++) {
232 TMCParticle * iparticle = (TMCParticle *) particles->At(i);
233 Int_t kf = iparticle->GetKF();
234 Int_t ks = iparticle->GetKS();
235 Int_t gc = fPythia->GetGeantCode(kf);
236 if (ks==1 && gc!=0 && KinematicSelection(iparticle)) {
237 nc++;
238//
239// store track information
240 p[0]=iparticle->GetPx();
241 p[1]=iparticle->GetPy();
242 p[2]=iparticle->GetPz();
243 origin[0]=origin0[0]+iparticle->GetVx()/10;
244 origin[1]=origin0[1]+iparticle->GetVy()/10;
245 origin[2]=origin0[2]+iparticle->GetVz()/10;
246 Float_t tof=kconv*iparticle->GetTime();
247 gAlice->SetTrack(fTrackIt,-1,gc,p,origin,polar,
248 tof,"Primary",nt);
249 gAlice->KeepTrack(nt);
250 } // select particle
251 } // particle loop
252 printf("\n I've put %i particles on the stack \n",nc);
253 } // mb ?
fe4da5cc 254 if (nc > 0) {
5be1fe76 255 jev+=nc;
fe4da5cc 256 if (jev >= fNpart) {
257 fKineBias=Float_t(fNpart)/Float_t(fTrials);
258 printf("\n Trials: %i\n",fTrials);
259 break;
260 }
261 }
262 } // event loop
263// adjust weight due to kinematic selection
264 AdjustWeights();
265// get cross-section
266 fXsection=fPythia->GetPARI(1);
267}
268
269Bool_t AliGenPythia::ParentSelected(Int_t ip)
270{
271 for (Int_t i=0; i<5; i++)
272 {
273 if (fParentSelect[i]==ip) return kTRUE;
274 }
275 return kFALSE;
276}
277
278Bool_t AliGenPythia::ChildSelected(Int_t ip)
279{
280 for (Int_t i=0; i<5; i++)
281 {
282 if (fChildSelect[i]==ip) return kTRUE;
283 }
284 return kFALSE;
285}
286
287Bool_t AliGenPythia::KinematicSelection(TMCParticle *particle)
288{
289 Float_t px=particle->GetPx();
290 Float_t py=particle->GetPy();
291 Float_t pz=particle->GetPz();
292 Float_t e=particle->GetEnergy();
293
294//
295// transverse momentum cut
296 Float_t pt=TMath::Sqrt(px*px+py*py);
297 if (pt > fPtMax || pt < fPtMin)
298 {
299// printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
300 return kFALSE;
301 }
302//
303// momentum cut
304 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
305 if (p > fPMax || p < fPMin)
306 {
307// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
308 return kFALSE;
309 }
310
311//
312// theta cut
5be1fe76 313 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
fe4da5cc 314 if (theta > fThetaMax || theta < fThetaMin)
315 {
316// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
317 return kFALSE;
318 }
319
320//
321// rapidity cut
322 Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
323 if (y > fYMax || y < fYMin)
324 {
325// printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
326 return kFALSE;
327 }
328
329//
330// phi cut
331 Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)))+TMath::Pi();
332 if (phi > fPhiMax || phi < fPhiMin)
333 {
334// printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
335 return kFALSE;
336 }
337
338 return kTRUE;
339}
340void AliGenPythia::AdjustWeights()
341{
342 TClonesArray *PartArray = gAlice->Particles();
343 GParticle *Part;
344 Int_t ntrack=gAlice->GetNtrack();
345 for (Int_t i=0; i<ntrack; i++) {
346 Part= (GParticle*) PartArray->UncheckedAt(i);
347 Part->SetWgt(Part->GetWgt()*fKineBias);
348 }
349}
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