1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
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12 * about the suitability of this software for any purpose. It is *
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14 **************************************************************************/
18 // Utility class to make simple Glauber type calculations
19 // for SYMMETRIC collision geometries (AA):
20 // Impact parameter, production points, reaction plane dependence
22 // The SimulateTrigger method can be used for simple MB and hard-process
23 // (binary scaling) trigger studies.
25 // Some basic quantities can be visualized directly.
27 // The default set-up for PbPb or AUAu collisions can be read from a file
28 // calling Init(1) or Init(2) if you want to read Almonds too.
30 // ***** If you change settings dont forget to call init afterwards, *****
31 // ***** in order to update the formulas with the new parameters. *****
33 // Author: andreas.morsch@cern.ch
34 //=================== Added by A. Dainese 11/02/04 ===========================
35 // Calculate path length for a parton with production point (x0,y0)
36 // and propagation direction (ux=cos(phi0),uy=sin(phi0))
37 // in a collision with impact parameter b and functions that make use
39 //=================== Added by A. Dainese 05/03/04 ===========================
40 // Calculation of line integrals I0 and I1
41 // integral0 = \int_0^ellCut dl*(T_A*T_B)(x0+l*ux,y0+l*uy)
42 // integral1 = \int_0^ellCut dl*l*(T_A*T_B)(x0+l*ux,y0+l*uy)
43 // mostly for use in the Quenching class
44 //=================== Added by C. Loizdes 27/03/04 ===========================
45 // Handling of AuAu collisions
46 // More get/set functions
47 // Comments, units and clearing of code
51 #include "AliFastGlauber.h"
63 #include <Riostream.h>
65 ClassImp(AliFastGlauber)
67 Float_t AliFastGlauber::fgBMax = 0.;
68 TF1* AliFastGlauber::fgWSb = NULL;
69 TF2* AliFastGlauber::fgWSbz = NULL;
70 TF1* AliFastGlauber::fgWSz = NULL;
71 TF1* AliFastGlauber::fgWSta = NULL;
72 TF2* AliFastGlauber::fgWStarfi = NULL;
73 TF2* AliFastGlauber::fgWAlmond = NULL;
74 TF1* AliFastGlauber::fgWStaa = NULL;
75 TF1* AliFastGlauber::fgWSgeo = NULL;
76 TF1* AliFastGlauber::fgWSbinary = NULL;
77 TF1* AliFastGlauber::fgWSN = NULL;
78 TF1* AliFastGlauber::fgWPathLength0 = NULL;
79 TF1* AliFastGlauber::fgWPathLength = NULL;
80 TF1* AliFastGlauber::fgWEnergyDensity = NULL;
81 TF1* AliFastGlauber::fgWIntRadius = NULL;
82 TF2* AliFastGlauber::fgWKParticipants = NULL;
83 TF1* AliFastGlauber::fgWParticipants = NULL;
84 TF2* AliFastGlauber::fgWAlmondCurrent = NULL;
85 TF2* AliFastGlauber::fgWAlmondFixedB[40];
86 const Int_t AliFastGlauber::fgkMCInts = 100000;
87 Int_t AliFastGlauber::fgCounter = 0;
89 AliFastGlauber::AliFastGlauber():
102 // Default Constructor
105 Error("AliFastGlauber","More than one instance (%d) is not supported, check your code!",fgCounter);
109 SetLengthDefinition();
113 AliFastGlauber::AliFastGlauber(const AliFastGlauber & gl)
131 AliFastGlauber::~AliFastGlauber()
135 for(Int_t k=0; k<40; k++) delete fgWAlmondFixedB[k];
138 void AliFastGlauber::SetAuAuRhic()
140 //Set all parameters for RHIC
141 SetWoodSaxonParametersAu();
142 SetHardCrossSection();
143 SetNNCrossSection(42);
145 SetFileName("$(ALICE_ROOT)/FASTSIM/data/glauberAuAu.root");
148 void AliFastGlauber::SetPbPbLHC()
150 //Set all parameters for LHC
151 SetWoodSaxonParametersPb();
152 SetHardCrossSection();
158 void AliFastGlauber::Init(Int_t mode)
161 // mode = 0; all functions are calculated
162 // mode = 1; overlap function is read from file (for Pb-Pb only)
163 // mode = 2; interaction almond functions are read from file
164 // USE THIS FOR PATH LENGTH CALC.!
174 fgWSb = new TF1("WSb", WSb, 0, fgBMax, 4);
175 fgWSb->SetParameter(0, fWSr0);
176 fgWSb->SetParameter(1, fWSd);
177 fgWSb->SetParameter(2, fWSw);
178 fgWSb->SetParameter(3, fWSn);
180 fgWSbz = new TF2("WSbz", WSbz, 0, fgBMax, 0, fgBMax, 4);
181 fgWSbz->SetParameter(0, fWSr0);
182 fgWSbz->SetParameter(1, fWSd);
183 fgWSbz->SetParameter(2, fWSw);
184 fgWSbz->SetParameter(3, fWSn);
186 fgWSz = new TF1("WSz", WSz, 0, fgBMax, 5);
187 fgWSz->SetParameter(0, fWSr0);
188 fgWSz->SetParameter(1, fWSd);
189 fgWSz->SetParameter(2, fWSw);
190 fgWSz->SetParameter(3, fWSn);
195 fgWSta = new TF1("WSta", WSta, 0., fgBMax, 0);
200 fgWStarfi = new TF2("WStarfi", WStarfi, 0., fgBMax, 0., TMath::Pi(), 1);
201 fgWStarfi->SetParameter(0, 0.);
202 fgWStarfi->SetNpx(200);
203 fgWStarfi->SetNpy(20);
206 // Participants Kernel
208 fgWKParticipants = new TF2("WKParticipants", WKParticipants, 0., fgBMax, 0., TMath::Pi(), 3);
209 fgWKParticipants->SetParameter(0, 0.);
210 fgWKParticipants->SetParameter(1, fSigmaNN);
211 fgWKParticipants->SetParameter(2, fA);
212 fgWKParticipants->SetNpx(200);
213 fgWKParticipants->SetNpy(20);
216 // Overlap and Participants
219 fgWStaa = new TF1("WStaa", WStaa, 0., fgBMax, 1);
220 fgWStaa->SetNpx(100);
221 fgWStaa->SetParameter(0,fA);
222 fgWStaa->SetNpx(100);
223 fgWParticipants = new TF1("WParticipants", WParticipants, 0., fgBMax, 2);
224 fgWParticipants->SetParameter(0, fSigmaNN);
225 fgWParticipants->SetParameter(1, fA);
226 fgWParticipants->SetNpx(100);
228 Info("Init","Reading overlap function from file %s",fName.Data());
229 TFile* f = new TFile(fName.Data());
231 Fatal("Init", "Could not open file %s",fName.Data());
233 fgWStaa = (TF1*) f->Get("WStaa");
234 fgWParticipants = (TF1*) f->Get("WParticipants");
241 fgWEnergyDensity = new TF1("WEnergyDensity", WEnergyDensity, 0., 2. * fWSr0, 1);
242 fgWEnergyDensity->SetParameter(0, fWSr0 + 1.);
245 // Geometrical Cross-Section
247 fgWSgeo = new TF1("WSgeo", WSgeo, 0., fgBMax, 1);
248 fgWSgeo->SetParameter(0,fSigmaNN); //mbarn
249 fgWSgeo->SetNpx(100);
252 // Hard cross section (binary collisions)
254 fgWSbinary = new TF1("WSbinary", WSbinary, 0., fgBMax, 1);
255 fgWSbinary->SetParameter(0, fSigmaHard); //mbarn
256 fgWSbinary->SetNpx(100);
259 // Hard collisions per event
261 fgWSN = new TF1("WSN", WSN, 0., fgBMax, 1);
265 // Almond shaped interaction region
267 fgWAlmond = new TF2("WAlmond", WAlmond, -fgBMax, fgBMax, -fgBMax, fgBMax, 1);
268 fgWAlmond->SetParameter(0, 0.);
269 fgWAlmond->SetNpx(200);
270 fgWAlmond->SetNpy(200);
273 Info("Init","Reading interaction almonds from file: %s",fName.Data());
274 Char_t almondName[100];
275 TFile* ff = new TFile(fName.Data());
276 for(Int_t k=0; k<40; k++) {
277 sprintf(almondName,"WAlmondFixedB%d",k);
278 fgWAlmondCurrent = (TF2*)ff->Get(almondName);
279 fgWAlmondFixedB[k] = fgWAlmondCurrent;
284 fgWIntRadius = new TF1("WIntRadius", WIntRadius, 0., fgBMax, 1);
285 fgWIntRadius->SetParameter(0, 0.);
288 // Path Length as a function of Phi
290 fgWPathLength0 = new TF1("WPathLength0", WPathLength0, -TMath::Pi(), TMath::Pi(), 2);
291 fgWPathLength0->SetParameter(0, 0.);
292 fgWPathLength0->SetParameter(1, 0.); //Pathlength definition
294 fgWPathLength = new TF1("WPathLength", WPathLength, -TMath::Pi(), TMath::Pi(), 3);
295 fgWPathLength->SetParameter(0, 0.); //Impact Parameter
296 fgWPathLength->SetParameter(1, 1000.); //Number of interactions used for average
297 fgWPathLength->SetParameter(2, 0); //Pathlength definition
300 void AliFastGlauber::Reset() const
303 // Reset dynamic allocated formulas
304 // in case init is called twice
306 if(fgWSb) delete fgWSb;
307 if(fgWSbz) delete fgWSbz;
308 if(fgWSz) delete fgWSz;
309 if(fgWSta) delete fgWSta;
310 if(fgWStarfi) delete fgWStarfi;
311 if(fgWAlmond) delete fgWAlmond;
312 if(fgWStaa) delete fgWStaa;
313 if(fgWSgeo) delete fgWSgeo;
314 if(fgWSbinary) delete fgWSbinary;
315 if(fgWSN) delete fgWSN;
316 if(fgWPathLength0) delete fgWPathLength0;
317 if(fgWPathLength) delete fgWPathLength;
318 if(fgWEnergyDensity) delete fgWEnergyDensity;
319 if(fgWIntRadius) delete fgWIntRadius;
320 if(fgWKParticipants) delete fgWKParticipants;
321 if(fgWParticipants) delete fgWParticipants;
324 void AliFastGlauber::DrawWSb() const
327 // Draw Wood-Saxon Nuclear Density Function
329 TCanvas *c1 = new TCanvas("c1","Wood Saxon",400,10,600,700);
331 Double_t max=fgWSb->GetMaximum(0,fgBMax)*1.01;
332 TH2F *h2f=new TH2F("h2fwsb","Wood Saxon: #rho(r) = n (1-#omega(r/r_{0})^2)/(1+exp((r-r_{0})/d)) [fm^{-3}]",2,0,fgBMax,2,0,max);
334 h2f->GetXaxis()->SetTitle("r [fm]");
335 h2f->GetYaxis()->SetNoExponent(kTRUE);
336 h2f->GetYaxis()->SetTitle("#rho [fm^{-3}]");
339 TLegend *l1a = new TLegend(0.45,0.6,.90,0.8);
340 l1a->SetFillStyle(0);
341 l1a->SetBorderSize(0);
343 sprintf(label,"r_{0} = %.2f fm",fWSr0);
344 l1a->AddEntry(fgWSb,label,"");
345 sprintf(label,"d = %.2f fm",fWSd);
346 l1a->AddEntry(fgWSb,label,"");
347 sprintf(label,"n = %.2e fm^{-3}",fWSn);
348 l1a->AddEntry(fgWSb,label,"");
349 sprintf(label,"#omega = %.2f",fWSw);
350 l1a->AddEntry(fgWSb,label,"");
355 void AliFastGlauber::DrawOverlap() const
358 // Draw Overlap Function
360 TCanvas *c2 = new TCanvas("c2","Overlap",400,10,600,700);
362 Double_t max=fgWStaa->GetMaximum(0,fgBMax)*1.01;
363 TH2F *h2f=new TH2F("h2ftaa","Overlap function: T_{AB} [mbarn^{-1}]",2,0,fgBMax,2,0, max);
365 h2f->GetXaxis()->SetTitle("b [fm]");
366 h2f->GetYaxis()->SetTitle("T_{AB} [mbarn^{-1}]");
368 fgWStaa->Draw("same");
371 void AliFastGlauber::DrawParticipants() const
374 // Draw Number of Participants Npart
376 TCanvas *c3 = new TCanvas("c3","Participants",400,10,600,700);
378 Double_t max=fgWParticipants->GetMaximum(0,fgBMax)*1.01;
379 TH2F *h2f=new TH2F("h2fpart","Number of Participants",2,0,fgBMax,2,0,max);
381 h2f->GetXaxis()->SetTitle("b [fm]");
382 h2f->GetYaxis()->SetTitle("N_{part}");
384 fgWParticipants->Draw("same");
385 TLegend *l1a = new TLegend(0.50,0.75,.90,0.9);
386 l1a->SetFillStyle(0);
387 l1a->SetBorderSize(0);
389 sprintf(label,"#sigma^{inel.}_{NN} = %.1f mbarn",fSigmaNN);
390 l1a->AddEntry(fgWParticipants,label,"");
395 void AliFastGlauber::DrawThickness() const
398 // Draw Thickness Function
400 TCanvas *c4 = new TCanvas("c4","Thickness",400,10,600,700);
402 Double_t max=fgWSta->GetMaximum(0,fgBMax)*1.01;
403 TH2F *h2f=new TH2F("h2fta","Thickness function: T_{A} [fm^{-2}]",2,0,fgBMax,2,0,max);
405 h2f->GetXaxis()->SetTitle("b [fm]");
406 h2f->GetYaxis()->SetTitle("T_{A} [fm^{-2}]");
408 fgWSta->Draw("same");
411 void AliFastGlauber::DrawGeo() const
414 // Draw Geometrical Cross-Section
416 TCanvas *c5 = new TCanvas("c5","Geometrical Cross-Section",400,10,600,700);
418 Double_t max=fgWSgeo->GetMaximum(0,fgBMax)*1.01;
419 TH2F *h2f=new TH2F("h2fgeo","Differential Geometrical Cross-Section: d#sigma^{geo}_{AB}/db [fm]",2,0,fgBMax,2,0,max);
421 h2f->GetXaxis()->SetTitle("b [fm]");
422 h2f->GetYaxis()->SetTitle("d#sigma^{geo}_{AB}/db [fm]");
424 fgWSgeo->Draw("same");
425 TLegend *l1a = new TLegend(0.10,0.8,.40,0.9);
426 l1a->SetFillStyle(0);
427 l1a->SetBorderSize(0);
429 sprintf(label,"#sigma_{NN}^{inel.} = %.1f mbarn",fSigmaNN);
430 l1a->AddEntry(fgWSgeo,label,"");
435 void AliFastGlauber::DrawBinary() const
438 // Draw Binary Cross-Section
440 TCanvas *c6 = new TCanvas("c6","Binary Cross-Section",400,10,600,700);
442 Double_t max=fgWSbinary->GetMaximum(0,fgBMax)*1.01;
443 TH2F *h2f=new TH2F("h2fbinary","Differential Binary Cross-Section: #sigma^{hard}_{NN} dT_{AB}/db [fm]",2,0,fgBMax,2,0,max);
445 h2f->GetXaxis()->SetTitle("b [fm]");
446 h2f->GetYaxis()->SetTitle("d#sigma^{hard}_{AB}/db [fm]");
448 fgWSbinary->Draw("same");
449 TLegend *l1a = new TLegend(0.50,0.8,.90,0.9);
450 l1a->SetFillStyle(0);
451 l1a->SetBorderSize(0);
453 sprintf(label,"#sigma_{NN}^{hard} = %.1f mbarn",fSigmaHard);
454 l1a->AddEntry(fgWSb,label,"");
459 void AliFastGlauber::DrawN() const
462 // Draw Binaries per event (Ncoll)
464 TCanvas *c7 = new TCanvas("c7","Binaries per event",400,10,600,700);
466 Double_t max=fgWSN->GetMaximum(0,fgBMax)*1.01;
467 TH2F *h2f=new TH2F("h2fhardcols","Number of hard collisions: T_{AB} #sigma^{hard}_{NN}/#sigma_{AB}^{geo}",2,0,fgBMax,2,0,max);
469 h2f->GetXaxis()->SetTitle("b [fm]");
470 h2f->GetYaxis()->SetTitle("N_{coll}");
473 TLegend *l1a = new TLegend(0.50,0.75,.90,0.9);
474 l1a->SetFillStyle(0);
475 l1a->SetBorderSize(0);
477 sprintf(label,"#sigma^{hard}_{NN} = %.1f mbarn",fSigmaHard);
478 l1a->AddEntry(fgWSN,label,"");
479 sprintf(label,"#sigma^{inel.}_{NN} = %.1f mbarn",fSigmaNN);
480 l1a->AddEntry(fgWSN,label,"");
485 void AliFastGlauber::DrawKernel(Double_t b) const
490 TCanvas *c8 = new TCanvas("c8","Kernel",400,10,600,700);
492 fgWStarfi->SetParameter(0, b);
493 TH2F *h2f=new TH2F("h2fkernel","Kernel of Overlap function: d^{2}T_{AB}/dr/d#phi [fm^{-3}]",2,0,fgBMax,2,0,TMath::Pi());
495 h2f->GetXaxis()->SetTitle("r [fm]");
496 h2f->GetYaxis()->SetTitle("#phi [rad]");
498 fgWStarfi->Draw("same");
499 TLegend *l1a = new TLegend(0.65,0.8,.90,0.9);
500 l1a->SetFillStyle(0);
501 l1a->SetBorderSize(0);
503 sprintf(label,"b = %.1f fm",b);
504 l1a->AddEntry(fgWStarfi,label,"");
509 void AliFastGlauber::DrawAlmond(Double_t b) const
512 // Draw Interaction Almond
514 TCanvas *c9 = new TCanvas("c9","Almond",400,10,600,700);
516 fgWAlmond->SetParameter(0, b);
517 TH2F *h2f=new TH2F("h2falmond","Interaction Almond [fm^{-4}]",2,0,fgBMax,2,0,fgBMax);
519 h2f->GetXaxis()->SetTitle("x [fm]");
520 h2f->GetYaxis()->SetTitle("y [fm]");
522 fgWAlmond->Draw("same");
523 TLegend *l1a = new TLegend(0.65,0.8,.90,0.9);
524 l1a->SetFillStyle(0);
525 l1a->SetBorderSize(0);
527 sprintf(label,"b = %.1f fm",b);
528 l1a->AddEntry(fgWAlmond,label,"");
533 void AliFastGlauber::DrawEnergyDensity() const
536 // Draw energy density
538 TCanvas *c10 = new TCanvas("c10","Energy Density",400, 10, 600, 700);
540 fgWEnergyDensity->SetMinimum(0.);
541 Double_t max=fgWEnergyDensity->GetMaximum(0,fgWEnergyDensity->GetParameter(0))*1.01;
542 TH2F *h2f=new TH2F("h2fenergydens","Energy density",2,0,fgBMax,2,0,max);
544 h2f->GetXaxis()->SetTitle("b [fm]");
545 h2f->GetYaxis()->SetTitle("fm^{-4}");
547 fgWEnergyDensity->Draw("same");
551 void AliFastGlauber::DrawPathLength0(Double_t b, Int_t iopt) const
556 TCanvas *c11 = new TCanvas("c11","Path Length",400,10,600,700);
558 fgWPathLength0->SetParameter(0, b);
559 fgWPathLength0->SetParameter(1, Double_t(iopt));
560 fgWPathLength0->SetMinimum(0.);
561 fgWPathLength0->SetMaximum(10.);
562 TH2F *h2f=new TH2F("h2fpathlength0","Path length",2,-TMath::Pi(), TMath::Pi(),2,0,10.);
564 h2f->GetXaxis()->SetTitle("#phi [rad]");
565 h2f->GetYaxis()->SetTitle("l [fm]");
567 fgWPathLength0->Draw("same");
570 void AliFastGlauber::DrawPathLength(Double_t b , Int_t ni, Int_t iopt) const
575 TCanvas *c12 = new TCanvas("c12","Path Length",400,10,600,700);
577 fgWAlmond->SetParameter(0, b);
578 fgWPathLength->SetParameter(0, b);
579 fgWPathLength->SetParameter(1, Double_t (ni));
580 fgWPathLength->SetParameter(2, Double_t (iopt));
581 fgWPathLength->SetMinimum(0.);
582 fgWPathLength->SetMaximum(10.);
583 TH2F *h2f=new TH2F("h2fpathlength","Path length",2,-TMath::Pi(), TMath::Pi(),2,0,10.);
585 h2f->GetXaxis()->SetTitle("#phi [rad]");
586 h2f->GetYaxis()->SetTitle("l [fm]");
588 fgWPathLength->Draw("same");
591 void AliFastGlauber::DrawIntRadius(Double_t b) const
594 // Draw Interaction Radius
596 TCanvas *c13 = new TCanvas("c13","Interaction Radius",400,10,600,700);
598 fgWIntRadius->SetParameter(0, b);
599 fgWIntRadius->SetMinimum(0);
600 Double_t max=fgWIntRadius->GetMaximum(0,fgBMax)*1.01;
601 TH2F *h2f=new TH2F("h2fintradius","Interaction Density",2,0.,fgBMax,2,0,max);
603 h2f->GetXaxis()->SetTitle("r [fm]");
604 h2f->GetYaxis()->SetTitle("[fm^{-3}]");
606 fgWIntRadius->Draw("same");
609 Double_t AliFastGlauber::WSb(Double_t* x, Double_t* par)
612 // Woods-Saxon Parameterisation
613 // as a function of radius (xx)
615 const Double_t kxx = x[0]; //fm
616 const Double_t kr0 = par[0]; //fm
617 const Double_t kd = par[1]; //fm
618 const Double_t kw = par[2]; //no units
619 const Double_t kn = par[3]; //fm^-3 (used to normalize integral to one)
620 Double_t y = kn * (1.+kw*(kxx/kr0)*(kxx/kr0))/(1.+TMath::Exp((kxx-kr0)/kd));
624 Double_t AliFastGlauber::WSbz(Double_t* x, Double_t* par)
627 // Wood Saxon Parameterisation
628 // as a function of z and b
630 const Double_t kbb = x[0]; //fm
631 const Double_t kzz = x[1]; //fm
632 const Double_t kr0 = par[0]; //fm
633 const Double_t kd = par[1]; //fm
634 const Double_t kw = par[2]; //no units
635 const Double_t kn = par[3]; //fm^-3 (used to normalize integral to one)
636 const Double_t kxx = TMath::Sqrt(kbb*kbb+kzz*kzz);
637 Double_t y = kn * (1.+kw*(kxx/kr0)*(kxx/kr0))/(1.+TMath::Exp((kxx-kr0)/kd));
641 Double_t AliFastGlauber::WSz(Double_t* x, Double_t* par)
644 // Wood Saxon Parameterisation
645 // as a function of z for fixed b
647 const Double_t kzz = x[0]; //fm
648 const Double_t kr0 = par[0]; //fm
649 const Double_t kd = par[1]; //fm
650 const Double_t kw = par[2]; //no units
651 const Double_t kn = par[3]; //fm^-3 (used to normalize integral to one)
652 const Double_t kbb = par[4]; //fm
653 const Double_t kxx = TMath::Sqrt(kbb*kbb+kzz*kzz);
654 Double_t y = kn * (1.+kw*(kxx/kr0)*(kxx/kr0))/(1.+TMath::Exp((kxx-kr0)/kd));
658 Double_t AliFastGlauber::WSta(Double_t* x, Double_t* /*par*/)
661 // Thickness function T_A
662 // as a function of b
664 const Double_t kb = x[0];
665 fgWSz->SetParameter(4, kb);
666 Double_t y = 2. * fgWSz->Integral(0., fgBMax);
670 Double_t AliFastGlauber::WStarfi(Double_t* x, Double_t* par)
673 // Kernel for overlap function: T_A(s)*T_A(s-b)
674 // as a function of r and phi
675 const Double_t kr1 = x[0];
676 const Double_t kphi = x[1];
677 const Double_t kb = par[0];
678 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
679 Double_t y = kr1 * fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
683 Double_t AliFastGlauber::WStaa(Double_t* x, Double_t* par)
687 // T_{AB}=Int d2s T_A(s)*T_B(s-b)
688 // as a function of b
689 // (normalized to fA*fB)
691 const Double_t kb = x[0];
692 const Double_t ka = par[0];
693 fgWStarfi->SetParameter(0, kb);
695 // root integration seems to fail
705 Double_t y = 2. * 208. * 208. * fgWStarfi->IntegralMultiple(2, al, bl, 0.001, err);
706 printf("WStaa: %.5e %.5e %.5e\n", b, y, err);
715 for (Int_t i = 0; i < fgkMCInts; i++)
718 const Double_t kphi = TMath::Pi() * gRandom->Rndm();
719 const Double_t kb1 = fgBMax * gRandom->Rndm();
720 y += fgWStarfi->Eval(kb1, kphi);
722 y *= 2. * TMath::Pi() * fgBMax / fgkMCInts; //fm^-2
723 y *= ka * ka * 0.1; //mbarn^-1
727 Double_t AliFastGlauber::WKParticipants(Double_t* x, Double_t* par)
730 // Kernel for number of participants
731 // as a function of r and phi
733 const Double_t kr1 = x[0];
734 const Double_t kphi = x[1];
735 const Double_t kb = par[0]; //fm
736 const Double_t ksig = par[1]; //mbarn
737 const Double_t ka = par[2]; //mass number
738 const Double_t kr2 = TMath::Sqrt(kr1*kr1 +kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
739 const Double_t kxsi = fgWSta->Eval(kr2) * ksig * 0.1; //no units
741 Double_t y=(1-TMath::Power((1-xsi),aa))
744 Double_t sum = ka * kxsi;
746 for (Int_t i = 1; i <= ka; i++)
749 sum *= (-kxsi) * a / Float_t(i+1);
752 y *= kr1 * fgWSta->Eval(kr1);
756 Double_t AliFastGlauber::WParticipants(Double_t* x, Double_t* par)
759 // Number of Participants as
762 const Double_t kb = x[0];
763 const Double_t ksig = par[0]; //mbarn
764 const Double_t ka = par[1]; //mass number
765 fgWKParticipants->SetParameter(0, kb);
766 fgWKParticipants->SetParameter(1, ksig);
767 fgWKParticipants->SetParameter(2, ka);
773 for (Int_t i = 0; i < fgkMCInts; i++)
775 const Double_t kphi = TMath::Pi() * gRandom->Rndm();
776 const Double_t kb1 = fgBMax * gRandom->Rndm();
777 y += fgWKParticipants->Eval(kb1, kphi);
779 y *= 2. * ka * 2. * TMath::Pi() * fgBMax / fgkMCInts;
783 Double_t AliFastGlauber::WSgeo(Double_t* x, Double_t* par)
786 // Geometrical Cross-Section
787 // as a function of b
789 const Double_t kb = x[0]; //fm
790 const Double_t ksigNN = par[0]; //mbarn
791 const Double_t ktaa = fgWStaa->Eval(kb); //mbarn^-1
792 Double_t y = 2. * TMath::Pi() * kb * (1. - TMath::Exp(- ksigNN * ktaa));
796 Double_t AliFastGlauber::WSbinary(Double_t* x, Double_t* par)
799 // Number of binary hard collisions
800 // as a function of b
802 const Double_t kb = x[0]; //fm
803 const Double_t ksig = par[0]; //mbarn
804 const Double_t ktaa = fgWStaa->Eval(kb); //mbarn^-1
805 Double_t y = 2. * TMath::Pi() * kb * ksig * ktaa;
809 Double_t AliFastGlauber::WSN(Double_t* x, Double_t* /*par*/)
812 // Number of hard processes per event
813 // as a function of b
814 const Double_t kb = x[0];
815 Double_t y = fgWSbinary->Eval(kb)/fgWSgeo->Eval(kb);
819 Double_t AliFastGlauber::WEnergyDensity(Double_t* x, Double_t* par)
822 // Initial energy density
823 // as a function of the impact parameter
825 const Double_t kb = x[0];
826 const Double_t krA = par[0];
828 // Attention: area of transverse reaction zone in hard-sphere approximation !
829 const Double_t krA2=krA*krA;
830 const Double_t kb2=kb*kb;
831 const Double_t ksaa = (TMath::Pi() - 2. * TMath::ASin(kb/ 2./ krA)) * krA2
832 - kb * TMath::Sqrt(krA2 - kb2/ 4.); //fm^2
833 const Double_t ktaa = fgWStaa->Eval(kb); //mbarn^-1
834 Double_t y=ktaa/ksaa*10;
838 Double_t AliFastGlauber::WAlmond(Double_t* x, Double_t* par)
841 // Almond shaped interaction region
842 // as a function of cartesian x,y.
844 const Double_t kb = par[0];
845 const Double_t kxx = x[0] + kb/2.;
846 const Double_t kyy = x[1];
847 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
848 const Double_t kphi = TMath::ATan2(kyy,kxx);
849 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
851 // Interaction probability calculated as product of thicknesses
853 Double_t y = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
857 Double_t AliFastGlauber::WIntRadius(Double_t* x, Double_t* par)
860 // Average interaction density over radius
861 // at which interaction takes place
862 // as a function of radius
864 const Double_t kr = x[0];
865 const Double_t kb = par[0];
866 fgWAlmond->SetParameter(0, kb);
867 // Average over phi in small steps
868 const Double_t kdphi = 2. * TMath::Pi() / 100.;
871 for (Int_t i = 0; i < 100; i++) {
872 const Double_t kxx = kr * TMath::Cos(phi);
873 const Double_t kyy = kr * TMath::Sin(phi);
874 y += fgWAlmond->Eval(kxx,kyy);
877 // Result multiplied by Jacobian (2 pi r)
878 y *= 2. * TMath::Pi() * kr / 100.;
882 Double_t AliFastGlauber::WPathLength0(Double_t* x, Double_t* par)
885 // Path Length as a function of phi
886 // for interaction point fixed at (0,0)
887 // as a function of phi-direction
889 // Phi direction in Almond
890 const Double_t kphi0 = x[0];
891 const Double_t kb = par[0];
892 // Path Length definition
893 const Int_t kiopt = Int_t(par[1]);
895 // Step along radial direction phi
896 const Int_t kNp = 100; // Steps in r
897 const Double_t kDr = fgBMax/kNp;
901 for (Int_t i = 0; i < kNp; i++) {
903 // Transform into target frame
905 const Double_t kxx = r * TMath::Cos(kphi0) + kb / 2.;
906 const Double_t kyy = r * TMath::Sin(kphi0);
907 const Double_t kphi = TMath::ATan2(kyy, kxx);
908 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
909 // Radius in projectile frame
910 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
911 const Double_t ky = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
919 if (!kiopt) // My length definition (is exact for hard disk)
920 if(w) y= 2. * rw / w;
922 const Double_t knorm=fgWSta->Eval(1e-4);
923 if(knorm) y = TMath::Sqrt(2. * rw * kDr / knorm / knorm);
928 Double_t AliFastGlauber::WPathLength(Double_t* x, Double_t* par)
931 // Path Length as a function of phi
932 // Interaction point from random distribution
933 // as a function of the phi-direction
934 const Double_t kphi0 = x[0];
935 const Double_t kb = par[0];
936 fgWAlmond->SetParameter(0, kb);
937 const Int_t kNpi = Int_t (par[1]); //Number of interactions
938 const Int_t kiopt = Int_t(par[2]); //Path Length definition
943 const Int_t kNp = 100;
944 const Double_t kDr = fgBMax/Double_t(kNp);
945 Double_t l = 0.; // Path length
946 for (Int_t in = 0; in < kNpi; in ++) {
951 fgWAlmond->GetRandom2(x0, y0);
953 const Double_t kr0 = TMath::Sqrt(x0*x0 + y0*y0);
954 const Int_t knps = Int_t ((fgBMax - kr0)/kDr) - 1;
958 for (Int_t i = 0; (i < knps ); i++) {
959 // Transform into target frame
960 const Double_t kxx = x0 + r * TMath::Cos(kphi0) + kb / 2.;
961 const Double_t kyy = y0 + r * TMath::Sin(kphi0);
962 const Double_t kphi = TMath::ATan2(kyy, kxx);
963 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
964 // Radius in projectile frame
965 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
966 const Double_t ky = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
972 // Average over interactions
974 if(w) l += (2. * rw / w);
976 const Double_t knorm=fgWSta->Eval(1e-4);
977 if(knorm) l+= 2. * rw * kDr / knorm / knorm;
984 ret=TMath::Sqrt( l / kNpi);
988 Double_t AliFastGlauber::CrossSection(Double_t b1, Double_t b2) const
991 // Return the geometrical cross-section integrated from b1 to b2
993 return fgWSgeo->Integral(b1, b2)*10.; //mbarn
996 Double_t AliFastGlauber::HardCrossSection(Double_t b1, Double_t b2) const
999 // Return the hard cross-section integrated from b1 to b2
1001 return fgWSbinary->Integral(b1, b2)*10.; //mbarn
1004 Double_t AliFastGlauber::FractionOfHardCrossSection(Double_t b1, Double_t b2) const
1007 // Return fraction of hard cross-section integrated from b1 to b2
1009 return fgWSbinary->Integral(b1, b2)/fgWSbinary->Integral(0., 100.);
1012 Double_t AliFastGlauber::NHard(Double_t b1, Double_t b2) const
1015 // Number of binary hard collisions
1016 // as a function of b (nucl/ex/0302016 eq. 19)
1018 const Double_t kshard=HardCrossSection(b1,b2);
1019 const Double_t ksgeo=CrossSection(b1,b2);
1021 return kshard/ksgeo;
1025 Double_t AliFastGlauber::Binaries(Double_t b) const
1028 // Return number of binary hard collisions normalized to 1 at b=0
1031 return fgWSN->Eval(b)/fgWSN->Eval(1e-4);
1034 Double_t AliFastGlauber::MeanOverlap(Double_t b1, Double_t b2)
1037 // Calculate the mean overlap for impact parameter range b1 .. b2
1043 while (b < b2-0.005) {
1044 Double_t nc = GetNumberOfCollisions(b);
1045 sum += 10. * fgWStaa->Eval(b) * fgWSgeo->Eval(b) * 0.01 / (1. - TMath::Exp(-nc));
1046 sumc += 10. * fgWSgeo->Eval(b) * 0.01;
1049 return (sum / CrossSection(b1, b2));
1053 Double_t AliFastGlauber::MeanNumberOfCollisionsPerEvent(Double_t b1, Double_t b2)
1056 // Calculate the mean number of collisions per event for impact parameter range b1 .. b2
1062 while (b < b2-0.005) {
1063 Double_t nc = GetNumberOfCollisions(b);
1064 sum += nc / (1. - TMath::Exp(-nc)) * 10. * fgWSgeo->Eval(b) * 0.01;
1065 sumc += 10. * fgWSgeo->Eval(b) * 0.01;
1068 return (sum / CrossSection(b1, b2));
1072 Double_t AliFastGlauber::GetNumberOfBinaries(Double_t b) const
1075 // Return number of binary hard collisions at b
1078 return fgWSN->Eval(b);
1081 Double_t AliFastGlauber::Participants(Double_t b) const
1084 // Return the number of participants normalized to 1 at b=0
1087 return (fgWParticipants->Eval(b)/fgWParticipants->Eval(1e-4));
1090 Double_t AliFastGlauber::GetNumberOfParticipants(Double_t b) const
1093 // Return the number of participants for impact parameter b
1096 return (fgWParticipants->Eval(b));
1099 Double_t AliFastGlauber::GetNumberOfCollisions(Double_t b) const
1102 // Return the number of collisions for impact parameter b
1105 return (fgWStaa->Eval(b)*fSigmaNN);
1108 Double_t AliFastGlauber::GetNumberOfCollisionsPerEvent(Double_t b) const
1111 // Return the number of collisions per event (at least one collision)
1112 // for impact parameter b
1114 Double_t n = GetNumberOfCollisions(b);
1116 return (n / (1. - TMath::Exp(- n)));
1122 void AliFastGlauber::SimulateTrigger(Int_t n)
1125 // Simulates Trigger
1127 TH1F* mbtH = new TH1F("mbtH", "MB Trigger b-Distribution", 100, 0., 20.);
1128 TH1F* hdtH = new TH1F("hdtH", "Hard Trigger b-Distribution", 100, 0., 20.);
1129 TH1F* mbmH = new TH1F("mbmH", "MB Trigger Multiplicity Distribution", 100, 0., 8000.);
1130 TH1F* hdmH = new TH1F("hdmH", "Hard Trigger Multiplicity Distribution", 100, 0., 8000.);
1132 mbtH->SetXTitle("b [fm]");
1133 hdtH->SetXTitle("b [fm]");
1134 mbmH->SetXTitle("Multiplicity");
1135 hdmH->SetXTitle("Multiplicity");
1137 TCanvas *c0 = new TCanvas("c0","Trigger Simulation",400,10,600,700);
1139 TCanvas *c1 = new TCanvas("c1","Trigger Simulation",400,10,600,700);
1145 for (Int_t iev = 0; iev < n; iev++)
1148 GetRandom(b, p, mult);
1151 mbmH->Fill(mult, 1.);
1152 hdmH->Fill(mult, p);
1168 void AliFastGlauber::GetRandom(Float_t& b, Float_t& p, Float_t& mult)
1171 // Gives back a random impact parameter, hard trigger probability and multiplicity
1173 b = fgWSgeo->GetRandom();
1174 const Float_t kmu = fgWSN->Eval(b);
1175 p = 1.-TMath::Exp(-kmu);
1176 mult = 6000./fgWSN->Eval(1.) * kmu;
1179 void AliFastGlauber::GetRandom(Int_t& bin, Bool_t& hard)
1182 // Gives back a random impact parameter bin, and hard trigger decission
1184 const Float_t kb = fgWSgeo->GetRandom();
1185 const Float_t kmu = fgWSN->Eval(kb) * fSigmaHard;
1186 const Float_t kp = 1.-TMath::Exp(-kmu);
1189 } else if (kb < 8.6) {
1191 } else if (kb < 11.2) {
1193 } else if (kb < 13.2) {
1195 } else if (kb < 15.0) {
1201 const Float_t kr = gRandom->Rndm();
1202 if (kr < kp) hard = kTRUE;
1205 Double_t AliFastGlauber::GetRandomImpactParameter(Double_t bmin, Double_t bmax)
1208 // Gives back a random impact parameter in the range bmin .. bmax
1211 while(b < bmin || b > bmax)
1212 b = fgWSgeo->GetRandom();
1216 void AliFastGlauber::StoreFunctions() const
1219 // Store in file functions
1221 TFile* ff = new TFile(fName.Data(),"recreate");
1222 fgWStaa->Write("WStaa");
1223 fgWParticipants->Write("WParticipants");
1228 //=================== Added by A. Dainese 11/02/04 ===========================
1230 void AliFastGlauber::StoreAlmonds() const
1234 // 40 almonds for b = (0.25+k*0.5) fm (k=0->39)
1236 Char_t almondName[100];
1237 TFile* ff = new TFile(fName.Data(),"update");
1238 for(Int_t k=0; k<40; k++) {
1239 sprintf(almondName,"WAlmondFixedB%d",k);
1240 Double_t b = 0.25+k*0.5;
1241 Info("StoreAlmonds"," b = %f\n",b);
1242 fgWAlmond->SetParameter(0,b);
1243 fgWAlmond->Write(almondName);
1249 void AliFastGlauber::SetCentralityClass(Double_t xsecFrLow,Double_t xsecFrUp)
1252 // Set limits of centrality class as fractions
1253 // of the geomtrical cross section
1255 if(xsecFrLow>1. || xsecFrUp>1. || xsecFrLow>xsecFrUp) {
1256 Error("SetCentralityClass", "Please set 0 <= xsecFrLow <= xsecFrUp <= 1\n");
1260 Double_t bLow=0.,bUp=0.;
1262 const Double_t knorm=fgWSgeo->Integral(0.,100.);
1263 while(xsecFr<xsecFrLow) {
1264 xsecFr = fgWSgeo->Integral(0.,bLow)/knorm;
1268 while(xsecFr<xsecFrUp) {
1269 xsecFr = fgWSgeo->Integral(0.,bUp)/knorm;
1273 Info("SetCentralityClass", "Centrality class: %4.2f-%4.2f; %4.1f < b < %4.1f fm",
1274 xsecFrLow,xsecFrUp,bLow,bUp);
1275 fgWSbinary->SetRange(bLow,bUp);
1281 void AliFastGlauber::GetRandomBHard(Double_t& b)
1284 // Get random impact parameter according to distribution of
1285 // hard (binary) cross-section, in the range defined by the centrality class
1287 b = fgWSbinary->GetRandom();
1288 Int_t bin = 2*(Int_t)b;
1289 if( (b-(Int_t)b) > 0.5) bin++;
1290 fgWAlmondCurrent = fgWAlmondFixedB[bin];
1294 void AliFastGlauber::GetRandomXY(Double_t& x,Double_t& y)
1297 // Get random position of parton production point according to
1298 // product of thickness functions
1300 fgWAlmondCurrent->GetRandom2(x,y);
1304 void AliFastGlauber::GetRandomPhi(Double_t& phi)
1307 // Get random parton azimuthal propagation direction
1309 phi = 2.*TMath::Pi()*gRandom->Rndm();
1313 Double_t AliFastGlauber::CalculateLength(Double_t b,Double_t x0,Double_t y0,Double_t phi0)
1316 // Calculate path length for a parton with production point (x0,y0)
1317 // and propagation direction (ux=cos(phi0),uy=sin(phi0))
1318 // in a collision with impact parameter b
1321 // number of steps in l
1322 const Int_t kNp = 100;
1323 const Double_t kDl = fgBMax/Double_t(kNp);
1329 // ell = 2 * \int_0^\infty dl*l*(T_A*T_B)(x0+l*ux,y0+l*uy) /
1330 // \int_0^\infty dl*(T_A*T_B)(x0+l*ux,y0+l*uy)
1334 const Double_t kr0 = TMath::Sqrt(x0*x0 + y0*y0);
1335 const Int_t knps = Int_t ((fgBMax - kr0)/kDl) - 1;
1337 Double_t integral1 = 0.;
1338 Double_t integral2 = 0.;
1340 for (Int_t i = 0; i < knps; i++) {
1342 // Transform into target frame
1343 const Double_t kxx = x0 + l * TMath::Cos(phi0) + b / 2.;
1344 const Double_t kyy = y0 + l * TMath::Sin(phi0);
1345 const Double_t kphi = TMath::ATan2(kyy, kxx);
1346 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
1347 // Radius in projectile frame
1348 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + b*b - 2.*kr1*b*TMath::Cos(kphi));
1349 const Double_t kprodTATB = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
1351 integral1 += kprodTATB * l * kDl;
1352 integral2 += kprodTATB * kDl;
1358 ell = (2. * integral1 / integral2);
1360 } else if(fEllDef==2) {
1364 // ell = \int_0^\infty dl*
1365 // \Theta((T_A*T_B)(x0+l*ux,y0+l*uy)-0.5*(T_A*T_B)(0,0))
1369 const Double_t kr0 = TMath::Sqrt(x0*x0 + y0*y0);
1370 const Int_t knps = Int_t ((fgBMax - kr0)/kDl) - 1;
1371 const Double_t kprodTATBHalfMax = 0.5*fgWAlmondCurrent->Eval(0.,0.);
1374 Double_t integral = 0.;
1375 for (Int_t i = 0; i < knps; i++) {
1376 // Transform into target frame
1377 const Double_t kxx = x0 + l * TMath::Cos(phi0) + b / 2.;
1378 const Double_t kyy = y0 + l * TMath::Sin(phi0);
1379 const Double_t kphi = TMath::ATan2(kyy, kxx);
1380 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
1381 // Radius in projectile frame
1382 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + b*b - 2.*kr1*b*TMath::Cos(kphi));
1383 const Double_t kprodTATB = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
1384 if(kprodTATB>kprodTATBHalfMax) integral += kDl;
1387 Double_t ell = integral;
1390 Error("CalculateLength","Wrong length definition setting: %d !\n",fEllDef);
1395 void AliFastGlauber::GetLengthAndPhi(Double_t& ell,Double_t& phi,Double_t b)
1398 // Return length from random b, x0, y0, phi0
1401 Double_t x0,y0,phi0;
1402 if(b<0.) GetRandomBHard(b);
1406 ell = CalculateLength(b,x0,y0,phi0);
1410 void AliFastGlauber::GetLength(Double_t& ell,Double_t b)
1413 // Return length from random b, x0, y0, phi0
1416 GetLengthAndPhi(ell,phi,b);
1420 void AliFastGlauber::GetLengthsBackToBackAndPhi(Double_t& ell1,Double_t& ell2,Double_t &phi,Double_t b)
1423 // Return 2 lengths back to back from random b, x0, y0, phi0
1426 Double_t x0,y0,phi0;
1427 if(b<0.) GetRandomBHard(b);
1430 const Double_t kphi0plusPi = phi0+TMath::Pi();
1432 ell1 = CalculateLength(b,x0,y0,phi0);
1433 ell2 = CalculateLength(b,x0,y0,kphi0plusPi);
1437 void AliFastGlauber::GetLengthsBackToBack(Double_t& ell1,Double_t& ell2,
1441 // Return 2 lengths back to back from random b, x0, y0, phi0
1444 GetLengthsBackToBackAndPhi(ell1,ell2,phi,b);
1448 void AliFastGlauber::GetLengthsForPythia(Int_t n,Double_t* phi,Double_t* ell, Double_t b)
1451 // Returns lenghts for n partons with azimuthal angles phi[n]
1452 // from random b, x0, y0
1455 if(b < 0.) GetRandomBHard(b);
1457 for(Int_t i = 0; i< n; i++) ell[i] = CalculateLength(b,x0,y0,phi[i]);
1461 void AliFastGlauber::PlotBDistr(Int_t n)
1464 // Plot distribution of n impact parameters
1467 TH1F *hB = new TH1F("hB","dN/db",100,0,fgBMax);
1468 hB->SetXTitle("b [fm]");
1469 hB->SetYTitle("dN/db [a.u.]");
1470 hB->SetFillColor(3);
1471 for(Int_t i=0; i<n; i++) {
1475 TCanvas *cB = new TCanvas("cB","Impact parameter distribution",0,0,500,500);
1481 void AliFastGlauber::PlotLengthDistr(Int_t n,Bool_t save,const char *fname)
1484 // Plot length distribution
1487 TH1F *hEll = new TH1F("hEll","Length distribution",64,-0.5,15);
1488 hEll->SetXTitle("Transverse path length, L [fm]");
1489 hEll->SetYTitle("Probability");
1490 hEll->SetFillColor(2);
1491 for(Int_t i=0; i<n; i++) {
1495 hEll->Scale(1/(Double_t)n);
1496 TCanvas *cL = new TCanvas("cL","Length distribution",0,0,500,500);
1501 TFile *f = new TFile(fname,"recreate");
1508 void AliFastGlauber::PlotLengthB2BDistr(Int_t n,Bool_t save,const char *fname)
1511 // Plot lengths back-to-back distributions
1514 TH2F *hElls = new TH2F("hElls","Lengths back-to-back",100,0,15,100,0,15);
1515 hElls->SetXTitle("Transverse path length, L [fm]");
1516 hElls->SetYTitle("Transverse path length, L [fm]");
1517 for(Int_t i=0; i<n; i++) {
1518 GetLengthsBackToBack(ell1,ell2);
1519 hElls->Fill(ell1,ell2);
1521 hElls->Scale(1/(Double_t)n);
1522 TCanvas *cLs = new TCanvas("cLs","Length back-to-back distribution",0,0,500,500);
1523 gStyle->SetPalette(1,0);
1525 hElls->Draw("col,Z");
1527 TFile *f = new TFile(fname,"recreate");
1534 void AliFastGlauber::PlotAlmonds() const
1537 // Plot almonds for some impact parameters
1539 TCanvas *c = new TCanvas("c","Almonds",0,0,500,500);
1540 gStyle->SetPalette(1,0);
1543 fgWAlmondFixedB[0]->Draw("cont1");
1545 fgWAlmondFixedB[10]->Draw("cont1");
1547 fgWAlmondFixedB[20]->Draw("cont1");
1549 fgWAlmondFixedB[30]->Draw("cont1");
1553 //=================== Added by A. Dainese 05/03/04 ===========================
1555 void AliFastGlauber::CalculateI0I1(Double_t& integral0,Double_t& integral1,
1556 Double_t b,Double_t x0,Double_t y0,
1557 Double_t phi0,Double_t ellCut) const
1560 // Calculate integrals:
1561 // integral0 = \int_0^ellCut dl*(T_A*T_B)(x0+l*ux,y0+l*uy)
1562 // integral1 = \int_0^ellCut dl*l*(T_A*T_B)(x0+l*ux,y0+l*uy)
1564 // for a parton with production point (x0,y0)
1565 // and propagation direction (ux=cos(phi0),uy=sin(phi0))
1566 // in a collision with impact parameter b
1569 // number of steps in l
1570 const Int_t kNp = 100;
1571 const Double_t kDl = fgBMax/Double_t(kNp);
1574 const Double_t kr0 = TMath::Sqrt(x0 * x0 + y0 * y0);
1575 const Int_t knps = Int_t ((fgBMax - kr0)/kDl) - 1;
1582 while((i < knps) && (l < ellCut)) {
1583 // Transform into target frame
1584 const Double_t kxx = x0 + l * TMath::Cos(phi0) + b / 2.;
1585 const Double_t kyy = y0 + l * TMath::Sin(phi0);
1586 const Double_t kphi = TMath::ATan2(kyy, kxx);
1587 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
1588 // Radius in projectile frame
1589 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + b*b - 2.*kr1*b*TMath::Cos(kphi));
1590 const Double_t kprodTATB = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
1591 integral0 += kprodTATB * kDl;
1592 integral1 += kprodTATB * l * kDl;
1599 void AliFastGlauber::GetI0I1AndPhi(Double_t& integral0,Double_t& integral1,
1601 Double_t ellCut,Double_t b)
1604 // Return I0 and I1 from random b, x0, y0, phi0
1607 Double_t x0,y0,phi0;
1608 if(b<0.) GetRandomBHard(b);
1612 CalculateI0I1(integral0,integral1,b,x0,y0,phi0,ellCut);
1616 void AliFastGlauber::GetI0I1(Double_t& integral0,Double_t& integral1,
1617 Double_t ellCut,Double_t b)
1620 // Return I0 and I1 from random b, x0, y0, phi0
1623 GetI0I1AndPhi(integral0,integral1,phi,ellCut,b);
1627 void AliFastGlauber::GetI0I1BackToBackAndPhi(Double_t& integral01,Double_t& integral11,
1628 Double_t& integral02,Double_t& integral12,
1630 Double_t ellCut,Double_t b)
1633 // Return 2 pairs of I0 and I1 back to back from random b, x0, y0, phi0
1636 Double_t x0,y0,phi0;
1637 if(b<0.) GetRandomBHard(b);
1641 const Double_t kphi0plusPi = phi0+TMath::Pi();
1642 CalculateI0I1(integral01,integral11,b,x0,y0,phi0,ellCut);
1643 CalculateI0I1(integral02,integral12,b,x0,y0,kphi0plusPi,ellCut);
1647 void AliFastGlauber::GetI0I1BackToBackAndPhiAndXY(Double_t& integral01,Double_t& integral11,
1648 Double_t& integral02,Double_t& integral12,
1649 Double_t& phi,Double_t &x,Double_t &y,
1650 Double_t ellCut,Double_t b)
1653 // Return 2 pairs of I0 and I1 back to back from random b, x0, y0, phi0
1656 Double_t x0,y0,phi0;
1657 if(b<0.) GetRandomBHard(b);
1660 phi = phi0; x=x0; y=y0;
1661 const Double_t kphi0plusPi = phi0+TMath::Pi();
1662 CalculateI0I1(integral01,integral11,b,x0,y0,phi0,ellCut);
1663 CalculateI0I1(integral02,integral12,b,x0,y0,kphi0plusPi,ellCut);
1667 void AliFastGlauber::GetI0I1BackToBack(Double_t& integral01,Double_t& integral11,
1668 Double_t& integral02,Double_t& integral12,
1669 Double_t ellCut,Double_t b)
1672 // Return 2 pairs of I0 and I1 back to back from random b, x0, y0, phi0
1675 GetI0I1BackToBackAndPhi(integral01,integral11,integral02,integral12,
1680 void AliFastGlauber::GetI0I1ForPythia(Int_t n,Double_t* phi,
1681 Double_t* integral0,Double_t* integral1,
1682 Double_t ellCut,Double_t b)
1685 // Returns I0 and I1 pairs for n partons with azimuthal angles phi[n]
1686 // from random b, x0, y0
1689 if(b<0.) GetRandomBHard(b);
1691 for(Int_t i=0; i<n; i++)
1692 CalculateI0I1(integral0[i],integral1[i],b,x0,y0,phi[i],ellCut);
1696 void AliFastGlauber::GetI0I1ForPythiaAndXY(Int_t n,Double_t* phi,
1697 Double_t* integral0,Double_t* integral1,
1698 Double_t &x,Double_t& y,
1699 Double_t ellCut,Double_t b)
1702 // Returns I0 and I1 pairs for n partons with azimuthal angles phi[n]
1703 // from random b, x0, y0 and return x0,y0
1706 if(b<0.) GetRandomBHard(b);
1708 for(Int_t i=0; i<n; i++)
1709 CalculateI0I1(integral0[i],integral1[i],b,x0,y0,phi[i],ellCut);
1715 void AliFastGlauber::PlotI0I1Distr(Int_t n,Double_t ellCut,
1716 Bool_t save,const char *fname)
1719 // Plot I0-I1 distribution
1722 TH2F *hI0I1s = new TH2F("hI0I1s","I_{0} versus I_{1}",1000,0,0.001,1000,0,0.01);
1723 hI0I1s->SetXTitle("I_{0} [fm^{-3}]");
1724 hI0I1s->SetYTitle("I_{1} [fm^{-2}]");
1726 TH1F *hI0 = new TH1F("hI0","I_{0} = #hat{q}L / k",
1728 hI0->SetXTitle("I_{0} [fm^{-3}]");
1729 hI0->SetYTitle("Probability");
1730 hI0->SetFillColor(3);
1731 TH1F *hI1 = new TH1F("hI1","I_{1} = #omega_{c} / k",
1733 hI1->SetXTitle("I_{1} [fm^{-2}]");
1734 hI1->SetYTitle("Probability");
1735 hI1->SetFillColor(4);
1736 TH1F *h2 = new TH1F("h2","2 I_{1}^{2}/I_{0} = R / k",
1738 h2->SetXTitle("2 I_{1}^{2}/I_{0} [fm^{-1}]");
1739 h2->SetYTitle("Probability");
1740 h2->SetFillColor(2);
1741 TH1F *h3 = new TH1F("h3","2 I_{1}/I_{0} = L",
1743 h3->SetXTitle("2 I_{1}/I_{0} [fm]");
1744 h3->SetYTitle("Probability");
1745 h3->SetFillColor(5);
1746 TH1F *h4 = new TH1F("h4","I_{0}^{2}/(2 I_{1}) = #hat{q} / k",
1748 h4->SetXTitle("I_{0}^{2}/(2 I_{1}) [fm^{-4}]");
1749 h4->SetYTitle("Probability");
1750 h4->SetFillColor(7);
1752 for(Int_t i=0; i<n; i++) {
1753 GetI0I1(i0,i1,ellCut);
1754 hI0I1s->Fill(i0,i1);
1757 h2->Fill(2.*i1*i1/i0);
1759 h4->Fill(i0*i0/2./i1);
1761 hI0->Scale(1/(Double_t)n);
1762 hI1->Scale(1/(Double_t)n);
1763 h2->Scale(1/(Double_t)n);
1764 h3->Scale(1/(Double_t)n);
1765 h4->Scale(1/(Double_t)n);
1766 hI0I1s->Scale(1/(Double_t)n);
1768 TCanvas *cI0I1 = new TCanvas("cI0I1","I0 and I1",0,0,900,700);
1781 gStyle->SetPalette(1,0);
1782 hI0I1s->Draw("col,Z");
1785 TFile *f = new TFile(fname,"recreate");
1797 void AliFastGlauber::PlotI0I1B2BDistr(Int_t n,Double_t ellCut,
1798 Bool_t save,const char *fname)
1801 // Plot I0-I1 back-to-back distributions
1803 Double_t i01,i11,i02,i12;
1804 TH2F *hI0s = new TH2F("hI0s","I_{0}'s back-to-back",100,0,100,100,0,100);
1805 hI0s->SetXTitle("I_{0} [fm^{-3}]");
1806 hI0s->SetYTitle("I_{0} [fm^{-3}]");
1807 TH2F *hI1s = new TH2F("hI1s","I_{1}'s back-to-back",100,0,100,100,0,100);
1808 hI1s->SetXTitle("I_{1} [fm^{-2}]");
1809 hI1s->SetYTitle("I_{1} [fm^{-2}]");
1811 for(Int_t i=0; i<n; i++) {
1812 GetI0I1BackToBack(i01,i11,i02,i12,ellCut);
1813 hI0s->Fill(i01,i02);
1814 hI1s->Fill(i11,i12);
1816 hI0s->Scale(1/(Double_t)n);
1817 hI1s->Scale(1/(Double_t)n);
1819 TCanvas *cI0I1s = new TCanvas("cI0I1s","I0 and I1 back-to-back distributions",0,0,800,400);
1820 gStyle->SetPalette(1,0);
1821 cI0I1s->Divide(2,1);
1823 hI0s->Draw("col,Z");
1825 hI1s->Draw("col,Z");
1828 TFile *f = new TFile(fname,"recreate");
1836 AliFastGlauber& AliFastGlauber::operator=(const AliFastGlauber& rhs)
1838 // Assignment operator
1843 void AliFastGlauber::Copy(TObject&) const
1848 Fatal("Copy","Not implemented!\n");