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. *
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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"
53 #include <Riostream.h>
66 ClassImp(AliFastGlauber)
68 Float_t AliFastGlauber::fgBMax = 0.;
69 TF1* AliFastGlauber::fgWSb = NULL;
70 TF2* AliFastGlauber::fgWSbz = NULL;
71 TF1* AliFastGlauber::fgWSz = NULL;
72 TF1* AliFastGlauber::fgWSta = NULL;
73 TF2* AliFastGlauber::fgWStarfi = NULL;
74 TF2* AliFastGlauber::fgWAlmond = NULL;
75 TF1* AliFastGlauber::fgWStaa = NULL;
76 TF1* AliFastGlauber::fgWSgeo = NULL;
77 TF1* AliFastGlauber::fgWSbinary = NULL;
78 TF1* AliFastGlauber::fgWSN = NULL;
79 TF1* AliFastGlauber::fgWPathLength0 = NULL;
80 TF1* AliFastGlauber::fgWPathLength = NULL;
81 TF1* AliFastGlauber::fgWEnergyDensity = NULL;
82 TF1* AliFastGlauber::fgWIntRadius = NULL;
83 TF2* AliFastGlauber::fgWKParticipants = NULL;
84 TF1* AliFastGlauber::fgWParticipants = NULL;
85 TF2* AliFastGlauber::fgWAlmondCurrent = NULL;
86 TF2* AliFastGlauber::fgWAlmondFixedB[40];
87 const Int_t AliFastGlauber::fgkMCInts = 100000;
88 Int_t AliFastGlauber::fgCounter = 0;
90 AliFastGlauber::AliFastGlauber():
103 // Default Constructor
106 Error("AliFastGlauber","More than one instance (%d) is not supported, check your code!",fgCounter);
110 SetLengthDefinition();
114 AliFastGlauber::AliFastGlauber(const AliFastGlauber & gl)
132 AliFastGlauber::~AliFastGlauber()
136 for(Int_t k=0; k<40; k++) delete fgWAlmondFixedB[k];
139 void AliFastGlauber::SetAuAuRhic()
141 //Set all parameters for RHIC
142 SetWoodSaxonParametersAu();
143 SetHardCrossSection();
144 SetNNCrossSection(42);
146 SetFileName("$(ALICE_ROOT)/FASTSIM/data/glauberAuAu.root");
149 void AliFastGlauber::SetPbPbLHC()
151 //Set all parameters for LHC
152 SetWoodSaxonParametersPb();
153 SetHardCrossSection();
159 void AliFastGlauber::Init(Int_t mode)
162 // mode = 0; all functions are calculated
163 // mode = 1; overlap function is read from file (for Pb-Pb only)
164 // mode = 2; interaction almond functions are read from file
165 // USE THIS FOR PATH LENGTH CALC.!
175 fgWSb = new TF1("WSb", WSb, 0, fgBMax, 4);
176 fgWSb->SetParameter(0, fWSr0);
177 fgWSb->SetParameter(1, fWSd);
178 fgWSb->SetParameter(2, fWSw);
179 fgWSb->SetParameter(3, fWSn);
181 fgWSbz = new TF2("WSbz", WSbz, 0, fgBMax, 0, fgBMax, 4);
182 fgWSbz->SetParameter(0, fWSr0);
183 fgWSbz->SetParameter(1, fWSd);
184 fgWSbz->SetParameter(2, fWSw);
185 fgWSbz->SetParameter(3, fWSn);
187 fgWSz = new TF1("WSz", WSz, 0, fgBMax, 5);
188 fgWSz->SetParameter(0, fWSr0);
189 fgWSz->SetParameter(1, fWSd);
190 fgWSz->SetParameter(2, fWSw);
191 fgWSz->SetParameter(3, fWSn);
196 fgWSta = new TF1("WSta", WSta, 0., fgBMax, 0);
201 fgWStarfi = new TF2("WStarfi", WStarfi, 0., fgBMax, 0., TMath::Pi(), 1);
202 fgWStarfi->SetParameter(0, 0.);
203 fgWStarfi->SetNpx(200);
204 fgWStarfi->SetNpy(20);
207 // Participants Kernel
209 fgWKParticipants = new TF2("WKParticipants", WKParticipants, 0., fgBMax, 0., TMath::Pi(), 3);
210 fgWKParticipants->SetParameter(0, 0.);
211 fgWKParticipants->SetParameter(1, fSigmaNN);
212 fgWKParticipants->SetParameter(2, fA);
213 fgWKParticipants->SetNpx(200);
214 fgWKParticipants->SetNpy(20);
217 // Overlap and Participants
220 fgWStaa = new TF1("WStaa", WStaa, 0., fgBMax, 1);
221 fgWStaa->SetNpx(100);
222 fgWStaa->SetParameter(0,fA);
223 fgWStaa->SetNpx(100);
224 fgWParticipants = new TF1("WParticipants", WParticipants, 0., fgBMax, 2);
225 fgWParticipants->SetParameter(0, fSigmaNN);
226 fgWParticipants->SetParameter(1, fA);
227 fgWParticipants->SetNpx(100);
229 Info("Init","Reading overlap function from file %s",fName.Data());
230 TFile* f = new TFile(fName.Data());
232 Fatal("Init", "Could not open file %s",fName.Data());
234 fgWStaa = (TF1*) f->Get("WStaa");
235 fgWParticipants = (TF1*) f->Get("WParticipants");
242 fgWEnergyDensity = new TF1("WEnergyDensity", WEnergyDensity, 0., 2. * fWSr0, 1);
243 fgWEnergyDensity->SetParameter(0, fWSr0 + 1.);
246 // Geometrical Cross-Section
248 fgWSgeo = new TF1("WSgeo", WSgeo, 0., fgBMax, 1);
249 fgWSgeo->SetParameter(0,fSigmaNN); //mbarn
250 fgWSgeo->SetNpx(100);
253 // Hard cross section (binary collisions)
255 fgWSbinary = new TF1("WSbinary", WSbinary, 0., fgBMax, 1);
256 fgWSbinary->SetParameter(0, fSigmaHard); //mbarn
257 fgWSbinary->SetNpx(100);
260 // Hard collisions per event
262 fgWSN = new TF1("WSN", WSN, 0., fgBMax, 1);
266 // Almond shaped interaction region
268 fgWAlmond = new TF2("WAlmond", WAlmond, -fgBMax, fgBMax, -fgBMax, fgBMax, 1);
269 fgWAlmond->SetParameter(0, 0.);
270 fgWAlmond->SetNpx(200);
271 fgWAlmond->SetNpy(200);
274 Info("Init","Reading interaction almonds from file: %s",fName.Data());
275 Char_t almondName[100];
276 TFile* ff = new TFile(fName.Data());
277 for(Int_t k=0; k<40; k++) {
278 sprintf(almondName,"WAlmondFixedB%d",k);
279 fgWAlmondCurrent = (TF2*)ff->Get(almondName);
280 fgWAlmondFixedB[k] = fgWAlmondCurrent;
285 fgWIntRadius = new TF1("WIntRadius", WIntRadius, 0., fgBMax, 1);
286 fgWIntRadius->SetParameter(0, 0.);
289 // Path Length as a function of Phi
291 fgWPathLength0 = new TF1("WPathLength0", WPathLength0, -TMath::Pi(), TMath::Pi(), 2);
292 fgWPathLength0->SetParameter(0, 0.);
293 fgWPathLength0->SetParameter(1, 0.); //Pathlength definition
295 fgWPathLength = new TF1("WPathLength", WPathLength, -TMath::Pi(), TMath::Pi(), 3);
296 fgWPathLength->SetParameter(0, 0.); //Impact Parameter
297 fgWPathLength->SetParameter(1, 1000.); //Number of interactions used for average
298 fgWPathLength->SetParameter(2, 0); //Pathlength definition
301 void AliFastGlauber::Reset() const
304 // Reset dynamic allocated formulas
305 // in case init is called twice
307 if(fgWSb) delete fgWSb;
308 if(fgWSbz) delete fgWSbz;
309 if(fgWSz) delete fgWSz;
310 if(fgWSta) delete fgWSta;
311 if(fgWStarfi) delete fgWStarfi;
312 if(fgWAlmond) delete fgWAlmond;
313 if(fgWStaa) delete fgWStaa;
314 if(fgWSgeo) delete fgWSgeo;
315 if(fgWSbinary) delete fgWSbinary;
316 if(fgWSN) delete fgWSN;
317 if(fgWPathLength0) delete fgWPathLength0;
318 if(fgWPathLength) delete fgWPathLength;
319 if(fgWEnergyDensity) delete fgWEnergyDensity;
320 if(fgWIntRadius) delete fgWIntRadius;
321 if(fgWKParticipants) delete fgWKParticipants;
322 if(fgWParticipants) delete fgWParticipants;
325 void AliFastGlauber::DrawWSb() const
328 // Draw Wood-Saxon Nuclear Density Function
330 TCanvas *c1 = new TCanvas("c1","Wood Saxon",400,10,600,700);
332 Double_t max=fgWSb->GetMaximum(0,fgBMax)*1.01;
333 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);
335 h2f->GetXaxis()->SetTitle("r [fm]");
336 h2f->GetYaxis()->SetNoExponent(kTRUE);
337 h2f->GetYaxis()->SetTitle("#rho [fm^{-3}]");
340 TLegend *l1a = new TLegend(0.45,0.6,.90,0.8);
341 l1a->SetFillStyle(0);
342 l1a->SetBorderSize(0);
344 sprintf(label,"r_{0} = %.2f fm",fWSr0);
345 l1a->AddEntry(fgWSb,label,"");
346 sprintf(label,"d = %.2f fm",fWSd);
347 l1a->AddEntry(fgWSb,label,"");
348 sprintf(label,"n = %.2e fm^{-3}",fWSn);
349 l1a->AddEntry(fgWSb,label,"");
350 sprintf(label,"#omega = %.2f",fWSw);
351 l1a->AddEntry(fgWSb,label,"");
356 void AliFastGlauber::DrawOverlap() const
359 // Draw Overlap Function
361 TCanvas *c2 = new TCanvas("c2","Overlap",400,10,600,700);
363 Double_t max=fgWStaa->GetMaximum(0,fgBMax)*1.01;
364 TH2F *h2f=new TH2F("h2ftaa","Overlap function: T_{AB} [mbarn^{-1}]",2,0,fgBMax,2,0, max);
366 h2f->GetXaxis()->SetTitle("b [fm]");
367 h2f->GetYaxis()->SetTitle("T_{AB} [mbarn^{-1}]");
369 fgWStaa->Draw("same");
372 void AliFastGlauber::DrawParticipants() const
375 // Draw Number of Participants Npart
377 TCanvas *c3 = new TCanvas("c3","Participants",400,10,600,700);
379 Double_t max=fgWParticipants->GetMaximum(0,fgBMax)*1.01;
380 TH2F *h2f=new TH2F("h2fpart","Number of Participants",2,0,fgBMax,2,0,max);
382 h2f->GetXaxis()->SetTitle("b [fm]");
383 h2f->GetYaxis()->SetTitle("N_{part}");
385 fgWParticipants->Draw("same");
386 TLegend *l1a = new TLegend(0.50,0.75,.90,0.9);
387 l1a->SetFillStyle(0);
388 l1a->SetBorderSize(0);
390 sprintf(label,"#sigma^{inel.}_{NN} = %.1f mbarn",fSigmaNN);
391 l1a->AddEntry(fgWParticipants,label,"");
396 void AliFastGlauber::DrawThickness() const
399 // Draw Thickness Function
401 TCanvas *c4 = new TCanvas("c4","Thickness",400,10,600,700);
403 Double_t max=fgWSta->GetMaximum(0,fgBMax)*1.01;
404 TH2F *h2f=new TH2F("h2fta","Thickness function: T_{A} [fm^{-2}]",2,0,fgBMax,2,0,max);
406 h2f->GetXaxis()->SetTitle("b [fm]");
407 h2f->GetYaxis()->SetTitle("T_{A} [fm^{-2}]");
409 fgWSta->Draw("same");
412 void AliFastGlauber::DrawGeo() const
415 // Draw Geometrical Cross-Section
417 TCanvas *c5 = new TCanvas("c5","Geometrical Cross-Section",400,10,600,700);
419 Double_t max=fgWSgeo->GetMaximum(0,fgBMax)*1.01;
420 TH2F *h2f=new TH2F("h2fgeo","Differential Geometrical Cross-Section: d#sigma^{geo}_{AB}/db [fm]",2,0,fgBMax,2,0,max);
422 h2f->GetXaxis()->SetTitle("b [fm]");
423 h2f->GetYaxis()->SetTitle("d#sigma^{geo}_{AB}/db [fm]");
425 fgWSgeo->Draw("same");
426 TLegend *l1a = new TLegend(0.10,0.8,.40,0.9);
427 l1a->SetFillStyle(0);
428 l1a->SetBorderSize(0);
430 sprintf(label,"#sigma_{NN}^{inel.} = %.1f mbarn",fSigmaNN);
431 l1a->AddEntry(fgWSgeo,label,"");
436 void AliFastGlauber::DrawBinary() const
439 // Draw Binary Cross-Section
441 TCanvas *c6 = new TCanvas("c6","Binary Cross-Section",400,10,600,700);
443 Double_t max=fgWSbinary->GetMaximum(0,fgBMax)*1.01;
444 TH2F *h2f=new TH2F("h2fbinary","Differential Binary Cross-Section: #sigma^{hard}_{NN} dT_{AB}/db [fm]",2,0,fgBMax,2,0,max);
446 h2f->GetXaxis()->SetTitle("b [fm]");
447 h2f->GetYaxis()->SetTitle("d#sigma^{hard}_{AB}/db [fm]");
449 fgWSbinary->Draw("same");
450 TLegend *l1a = new TLegend(0.50,0.8,.90,0.9);
451 l1a->SetFillStyle(0);
452 l1a->SetBorderSize(0);
454 sprintf(label,"#sigma_{NN}^{hard} = %.1f mbarn",fSigmaHard);
455 l1a->AddEntry(fgWSb,label,"");
460 void AliFastGlauber::DrawN() const
463 // Draw Binaries per event (Ncoll)
465 TCanvas *c7 = new TCanvas("c7","Binaries per event",400,10,600,700);
467 Double_t max=fgWSN->GetMaximum(0,fgBMax)*1.01;
468 TH2F *h2f=new TH2F("h2fhardcols","Number of hard collisions: T_{AB} #sigma^{hard}_{NN}/#sigma_{AB}^{geo}",2,0,fgBMax,2,0,max);
470 h2f->GetXaxis()->SetTitle("b [fm]");
471 h2f->GetYaxis()->SetTitle("N_{coll}");
474 TLegend *l1a = new TLegend(0.50,0.75,.90,0.9);
475 l1a->SetFillStyle(0);
476 l1a->SetBorderSize(0);
478 sprintf(label,"#sigma^{hard}_{NN} = %.1f mbarn",fSigmaHard);
479 l1a->AddEntry(fgWSN,label,"");
480 sprintf(label,"#sigma^{inel.}_{NN} = %.1f mbarn",fSigmaNN);
481 l1a->AddEntry(fgWSN,label,"");
486 void AliFastGlauber::DrawKernel(Double_t b) const
491 TCanvas *c8 = new TCanvas("c8","Kernel",400,10,600,700);
493 fgWStarfi->SetParameter(0, b);
494 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());
496 h2f->GetXaxis()->SetTitle("r [fm]");
497 h2f->GetYaxis()->SetTitle("#phi [rad]");
499 fgWStarfi->Draw("same");
500 TLegend *l1a = new TLegend(0.65,0.8,.90,0.9);
501 l1a->SetFillStyle(0);
502 l1a->SetBorderSize(0);
504 sprintf(label,"b = %.1f fm",b);
505 l1a->AddEntry(fgWStarfi,label,"");
510 void AliFastGlauber::DrawAlmond(Double_t b) const
513 // Draw Interaction Almond
515 TCanvas *c9 = new TCanvas("c9","Almond",400,10,600,700);
517 fgWAlmond->SetParameter(0, b);
518 TH2F *h2f=new TH2F("h2falmond","Interaction Almond [fm^{-4}]",2,0,fgBMax,2,0,fgBMax);
520 h2f->GetXaxis()->SetTitle("x [fm]");
521 h2f->GetYaxis()->SetTitle("y [fm]");
523 fgWAlmond->Draw("same");
524 TLegend *l1a = new TLegend(0.65,0.8,.90,0.9);
525 l1a->SetFillStyle(0);
526 l1a->SetBorderSize(0);
528 sprintf(label,"b = %.1f fm",b);
529 l1a->AddEntry(fgWAlmond,label,"");
534 void AliFastGlauber::DrawEnergyDensity() const
537 // Draw energy density
539 TCanvas *c10 = new TCanvas("c10","Energy Density",400, 10, 600, 700);
541 fgWEnergyDensity->SetMinimum(0.);
542 Double_t max=fgWEnergyDensity->GetMaximum(0,fgWEnergyDensity->GetParameter(0))*1.01;
543 TH2F *h2f=new TH2F("h2fenergydens","Energy density",2,0,fgBMax,2,0,max);
545 h2f->GetXaxis()->SetTitle("b [fm]");
546 h2f->GetYaxis()->SetTitle("fm^{-4}");
548 fgWEnergyDensity->Draw("same");
552 void AliFastGlauber::DrawPathLength0(Double_t b, Int_t iopt) const
557 TCanvas *c11 = new TCanvas("c11","Path Length",400,10,600,700);
559 fgWPathLength0->SetParameter(0, b);
560 fgWPathLength0->SetParameter(1, Double_t(iopt));
561 fgWPathLength0->SetMinimum(0.);
562 fgWPathLength0->SetMaximum(10.);
563 TH2F *h2f=new TH2F("h2fpathlength0","Path length",2,-TMath::Pi(), TMath::Pi(),2,0,10.);
565 h2f->GetXaxis()->SetTitle("#phi [rad]");
566 h2f->GetYaxis()->SetTitle("l [fm]");
568 fgWPathLength0->Draw("same");
571 void AliFastGlauber::DrawPathLength(Double_t b , Int_t ni, Int_t iopt) const
576 TCanvas *c12 = new TCanvas("c12","Path Length",400,10,600,700);
578 fgWAlmond->SetParameter(0, b);
579 fgWPathLength->SetParameter(0, b);
580 fgWPathLength->SetParameter(1, Double_t (ni));
581 fgWPathLength->SetParameter(2, Double_t (iopt));
582 fgWPathLength->SetMinimum(0.);
583 fgWPathLength->SetMaximum(10.);
584 TH2F *h2f=new TH2F("h2fpathlength","Path length",2,-TMath::Pi(), TMath::Pi(),2,0,10.);
586 h2f->GetXaxis()->SetTitle("#phi [rad]");
587 h2f->GetYaxis()->SetTitle("l [fm]");
589 fgWPathLength->Draw("same");
592 void AliFastGlauber::DrawIntRadius(Double_t b) const
595 // Draw Interaction Radius
597 TCanvas *c13 = new TCanvas("c13","Interaction Radius",400,10,600,700);
599 fgWIntRadius->SetParameter(0, b);
600 fgWIntRadius->SetMinimum(0);
601 Double_t max=fgWIntRadius->GetMaximum(0,fgBMax)*1.01;
602 TH2F *h2f=new TH2F("h2fintradius","Interaction Density",2,0.,fgBMax,2,0,max);
604 h2f->GetXaxis()->SetTitle("r [fm]");
605 h2f->GetYaxis()->SetTitle("[fm^{-3}]");
607 fgWIntRadius->Draw("same");
610 Double_t AliFastGlauber::WSb(Double_t* x, Double_t* par)
613 // Woods-Saxon Parameterisation
614 // as a function of radius (xx)
616 const Double_t kxx = x[0]; //fm
617 const Double_t kr0 = par[0]; //fm
618 const Double_t kd = par[1]; //fm
619 const Double_t kw = par[2]; //no units
620 const Double_t kn = par[3]; //fm^-3 (used to normalize integral to one)
621 Double_t y = kn * (1.+kw*(kxx/kr0)*(kxx/kr0))/(1.+TMath::Exp((kxx-kr0)/kd));
625 Double_t AliFastGlauber::WSbz(Double_t* x, Double_t* par)
628 // Wood Saxon Parameterisation
629 // as a function of z and b
631 const Double_t kbb = x[0]; //fm
632 const Double_t kzz = x[1]; //fm
633 const Double_t kr0 = par[0]; //fm
634 const Double_t kd = par[1]; //fm
635 const Double_t kw = par[2]; //no units
636 const Double_t kn = par[3]; //fm^-3 (used to normalize integral to one)
637 const Double_t kxx = TMath::Sqrt(kbb*kbb+kzz*kzz);
638 Double_t y = kn * (1.+kw*(kxx/kr0)*(kxx/kr0))/(1.+TMath::Exp((kxx-kr0)/kd));
642 Double_t AliFastGlauber::WSz(Double_t* x, Double_t* par)
645 // Wood Saxon Parameterisation
646 // as a function of z for fixed b
648 const Double_t kzz = x[0]; //fm
649 const Double_t kr0 = par[0]; //fm
650 const Double_t kd = par[1]; //fm
651 const Double_t kw = par[2]; //no units
652 const Double_t kn = par[3]; //fm^-3 (used to normalize integral to one)
653 const Double_t kbb = par[4]; //fm
654 const Double_t kxx = TMath::Sqrt(kbb*kbb+kzz*kzz);
655 Double_t y = kn * (1.+kw*(kxx/kr0)*(kxx/kr0))/(1.+TMath::Exp((kxx-kr0)/kd));
659 Double_t AliFastGlauber::WSta(Double_t* x, Double_t* /*par*/)
662 // Thickness function T_A
663 // as a function of b
665 const Double_t kb = x[0];
666 fgWSz->SetParameter(4, kb);
667 Double_t y = 2. * fgWSz->Integral(0., fgBMax);
671 Double_t AliFastGlauber::WStarfi(Double_t* x, Double_t* par)
674 // Kernel for overlap function: T_A(s)*T_A(s-b)
675 // as a function of r and phi
676 const Double_t kr1 = x[0];
677 const Double_t kphi = x[1];
678 const Double_t kb = par[0];
679 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
680 Double_t y = kr1 * fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
684 Double_t AliFastGlauber::WStaa(Double_t* x, Double_t* par)
688 // T_{AB}=Int d2s T_A(s)*T_B(s-b)
689 // as a function of b
690 // (normalized to fA*fB)
692 const Double_t kb = x[0];
693 const Double_t ka = par[0];
694 fgWStarfi->SetParameter(0, kb);
696 // root integration seems to fail
706 Double_t y = 2. * 208. * 208. * fgWStarfi->IntegralMultiple(2, al, bl, 0.001, err);
707 printf("WStaa: %.5e %.5e %.5e\n", b, y, err);
716 for (Int_t i = 0; i < fgkMCInts; i++)
719 const Double_t kphi = TMath::Pi() * gRandom->Rndm();
720 const Double_t kb1 = fgBMax * gRandom->Rndm();
721 y += fgWStarfi->Eval(kb1, kphi);
723 y *= 2. * TMath::Pi() * fgBMax / fgkMCInts; //fm^-2
724 y *= ka * ka * 0.1; //mbarn^-1
728 Double_t AliFastGlauber::WKParticipants(Double_t* x, Double_t* par)
731 // Kernel for number of participants
732 // as a function of r and phi
734 const Double_t kr1 = x[0];
735 const Double_t kphi = x[1];
736 const Double_t kb = par[0]; //fm
737 const Double_t ksig = par[1]; //mbarn
738 const Double_t ka = par[2]; //mass number
739 const Double_t kr2 = TMath::Sqrt(kr1*kr1 +kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
740 const Double_t kxsi = fgWSta->Eval(kr2) * ksig * 0.1; //no units
742 Double_t y=(1-TMath::Power((1-xsi),aa))
745 Double_t sum = ka * kxsi;
747 for (Int_t i = 1; i <= ka; i++)
750 sum *= (-kxsi) * a / Float_t(i+1);
753 y *= kr1 * fgWSta->Eval(kr1);
757 Double_t AliFastGlauber::WParticipants(Double_t* x, Double_t* par)
760 // Number of Participants as
763 const Double_t kb = x[0];
764 const Double_t ksig = par[0]; //mbarn
765 const Double_t ka = par[1]; //mass number
766 fgWKParticipants->SetParameter(0, kb);
767 fgWKParticipants->SetParameter(1, ksig);
768 fgWKParticipants->SetParameter(2, ka);
774 for (Int_t i = 0; i < fgkMCInts; i++)
776 const Double_t kphi = TMath::Pi() * gRandom->Rndm();
777 const Double_t kb1 = fgBMax * gRandom->Rndm();
778 y += fgWKParticipants->Eval(kb1, kphi);
780 y *= 2. * ka * 2. * TMath::Pi() * fgBMax / fgkMCInts;
784 Double_t AliFastGlauber::WSgeo(Double_t* x, Double_t* par)
787 // Geometrical Cross-Section
788 // as a function of b
790 const Double_t kb = x[0]; //fm
791 const Double_t ksigNN = par[0]; //mbarn
792 const Double_t ktaa = fgWStaa->Eval(kb); //mbarn^-1
793 Double_t y = 2. * TMath::Pi() * kb * (1. - TMath::Exp(- ksigNN * ktaa));
797 Double_t AliFastGlauber::WSbinary(Double_t* x, Double_t* par)
800 // Number of binary hard collisions
801 // as a function of b
803 const Double_t kb = x[0]; //fm
804 const Double_t ksig = par[0]; //mbarn
805 const Double_t ktaa = fgWStaa->Eval(kb); //mbarn^-1
806 Double_t y = 2. * TMath::Pi() * kb * ksig * ktaa;
810 Double_t AliFastGlauber::WSN(Double_t* x, Double_t* /*par*/)
813 // Number of hard processes per event
814 // as a function of b
815 const Double_t kb = x[0];
816 Double_t y = fgWSbinary->Eval(kb)/fgWSgeo->Eval(kb);
820 Double_t AliFastGlauber::WEnergyDensity(Double_t* x, Double_t* par)
823 // Initial energy density
824 // as a function of the impact parameter
826 const Double_t kb = x[0];
827 const Double_t krA = par[0];
829 // Attention: area of transverse reaction zone in hard-sphere approximation !
830 const Double_t krA2=krA*krA;
831 const Double_t kb2=kb*kb;
832 const Double_t ksaa = (TMath::Pi() - 2. * TMath::ASin(kb/ 2./ krA)) * krA2
833 - kb * TMath::Sqrt(krA2 - kb2/ 4.); //fm^2
834 const Double_t ktaa = fgWStaa->Eval(kb); //mbarn^-1
835 Double_t y=ktaa/ksaa*10;
839 Double_t AliFastGlauber::WAlmond(Double_t* x, Double_t* par)
842 // Almond shaped interaction region
843 // as a function of cartesian x,y.
845 const Double_t kb = par[0];
846 const Double_t kxx = x[0] + kb/2.;
847 const Double_t kyy = x[1];
848 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
849 const Double_t kphi = TMath::ATan2(kyy,kxx);
850 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
852 // Interaction probability calculated as product of thicknesses
854 Double_t y = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
858 Double_t AliFastGlauber::WIntRadius(Double_t* x, Double_t* par)
861 // Average interaction density over radius
862 // at which interaction takes place
863 // as a function of radius
865 const Double_t kr = x[0];
866 const Double_t kb = par[0];
867 fgWAlmond->SetParameter(0, kb);
868 // Average over phi in small steps
869 const Double_t kdphi = 2. * TMath::Pi() / 100.;
872 for (Int_t i = 0; i < 100; i++) {
873 const Double_t kxx = kr * TMath::Cos(phi);
874 const Double_t kyy = kr * TMath::Sin(phi);
875 y += fgWAlmond->Eval(kxx,kyy);
878 // Result multiplied by Jacobian (2 pi r)
879 y *= 2. * TMath::Pi() * kr / 100.;
883 Double_t AliFastGlauber::WPathLength0(Double_t* x, Double_t* par)
886 // Path Length as a function of phi
887 // for interaction point fixed at (0,0)
888 // as a function of phi-direction
890 // Phi direction in Almond
891 const Double_t kphi0 = x[0];
892 const Double_t kb = par[0];
893 // Path Length definition
894 const Int_t kiopt = Int_t(par[1]);
896 // Step along radial direction phi
897 const Int_t kNp = 100; // Steps in r
898 const Double_t kDr = fgBMax/kNp;
902 for (Int_t i = 0; i < kNp; i++) {
904 // Transform into target frame
906 const Double_t kxx = r * TMath::Cos(kphi0) + kb / 2.;
907 const Double_t kyy = r * TMath::Sin(kphi0);
908 const Double_t kphi = TMath::ATan2(kyy, kxx);
909 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
910 // Radius in projectile frame
911 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
912 const Double_t ky = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
920 if (!kiopt) // My length definition (is exact for hard disk)
921 if(w) y= 2. * rw / w;
923 const Double_t knorm=fgWSta->Eval(1e-4);
924 if(knorm) y = TMath::Sqrt(2. * rw * kDr / knorm / knorm);
929 Double_t AliFastGlauber::WPathLength(Double_t* x, Double_t* par)
932 // Path Length as a function of phi
933 // Interaction point from random distribution
934 // as a function of the phi-direction
935 const Double_t kphi0 = x[0];
936 const Double_t kb = par[0];
937 fgWAlmond->SetParameter(0, kb);
938 const Int_t kNpi = Int_t (par[1]); //Number of interactions
939 const Int_t kiopt = Int_t(par[2]); //Path Length definition
944 const Int_t kNp = 100;
945 const Double_t kDr = fgBMax/Double_t(kNp);
946 Double_t l = 0.; // Path length
947 for (Int_t in = 0; in < kNpi; in ++) {
952 fgWAlmond->GetRandom2(x0, y0);
954 const Double_t kr0 = TMath::Sqrt(x0*x0 + y0*y0);
955 const Int_t knps = Int_t ((fgBMax - kr0)/kDr) - 1;
959 for (Int_t i = 0; (i < knps ); i++) {
960 // Transform into target frame
961 const Double_t kxx = x0 + r * TMath::Cos(kphi0) + kb / 2.;
962 const Double_t kyy = y0 + r * TMath::Sin(kphi0);
963 const Double_t kphi = TMath::ATan2(kyy, kxx);
964 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
965 // Radius in projectile frame
966 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + kb*kb - 2.*kr1*kb*TMath::Cos(kphi));
967 const Double_t ky = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
973 // Average over interactions
975 if(w) l += (2. * rw / w);
977 const Double_t knorm=fgWSta->Eval(1e-4);
978 if(knorm) l+= 2. * rw * kDr / knorm / knorm;
985 ret=TMath::Sqrt( l / kNpi);
989 Double_t AliFastGlauber::CrossSection(Double_t b1, Double_t b2) const
992 // Return the geometrical cross-section integrated from b1 to b2
994 return fgWSgeo->Integral(b1, b2)*10.; //mbarn
997 Double_t AliFastGlauber::HardCrossSection(Double_t b1, Double_t b2) const
1000 // Return the hard cross-section integrated from b1 to b2
1002 return fgWSbinary->Integral(b1, b2)*10.; //mbarn
1005 Double_t AliFastGlauber::FractionOfHardCrossSection(Double_t b1, Double_t b2) const
1008 // Return fraction of hard cross-section integrated from b1 to b2
1010 return fgWSbinary->Integral(b1, b2)/fgWSbinary->Integral(0., 100.);
1013 Double_t AliFastGlauber::NHard(Double_t b1, Double_t b2) const
1016 // Number of binary hard collisions
1017 // as a function of b (nucl/ex/0302016 eq. 19)
1019 const Double_t kshard=HardCrossSection(b1,b2);
1020 const Double_t ksgeo=CrossSection(b1,b2);
1022 return kshard/ksgeo;
1026 Double_t AliFastGlauber::Binaries(Double_t b) const
1029 // Return number of binary hard collisions normalized to 1 at b=0
1032 return fgWSN->Eval(b)/fgWSN->Eval(1e-4);
1035 Double_t AliFastGlauber::MeanOverlap(Double_t b1, Double_t b2)
1038 // Calculate the mean overlap for impact parameter range b1 .. b2
1044 while (b < b2-0.005) {
1045 Double_t nc = GetNumberOfCollisions(b);
1046 sum += 10. * fgWStaa->Eval(b) * fgWSgeo->Eval(b) * 0.01 / (1. - TMath::Exp(-nc));
1047 sumc += 10. * fgWSgeo->Eval(b) * 0.01;
1050 return (sum / CrossSection(b1, b2));
1054 Double_t AliFastGlauber::MeanNumberOfCollisionsPerEvent(Double_t b1, Double_t b2)
1057 // Calculate the mean number of collisions per event for impact parameter range b1 .. b2
1063 while (b < b2-0.005) {
1064 Double_t nc = GetNumberOfCollisions(b);
1065 sum += nc / (1. - TMath::Exp(-nc)) * 10. * fgWSgeo->Eval(b) * 0.01;
1066 sumc += 10. * fgWSgeo->Eval(b) * 0.01;
1069 return (sum / CrossSection(b1, b2));
1073 Double_t AliFastGlauber::GetNumberOfBinaries(Double_t b) const
1076 // Return number of binary hard collisions at b
1079 return fgWSN->Eval(b);
1082 Double_t AliFastGlauber::Participants(Double_t b) const
1085 // Return the number of participants normalized to 1 at b=0
1088 return (fgWParticipants->Eval(b)/fgWParticipants->Eval(1e-4));
1091 Double_t AliFastGlauber::GetNumberOfParticipants(Double_t b) const
1094 // Return the number of participants for impact parameter b
1097 return (fgWParticipants->Eval(b));
1100 Double_t AliFastGlauber::GetNumberOfCollisions(Double_t b) const
1103 // Return the number of collisions for impact parameter b
1106 return (fgWStaa->Eval(b)*fSigmaNN);
1109 Double_t AliFastGlauber::GetNumberOfCollisionsPerEvent(Double_t b) const
1112 // Return the number of collisions per event (at least one collision)
1113 // for impact parameter b
1115 Double_t n = GetNumberOfCollisions(b);
1117 return (n / (1. - TMath::Exp(- n)));
1123 void AliFastGlauber::SimulateTrigger(Int_t n)
1126 // Simulates Trigger
1128 TH1F* mbtH = new TH1F("mbtH", "MB Trigger b-Distribution", 100, 0., 20.);
1129 TH1F* hdtH = new TH1F("hdtH", "Hard Trigger b-Distribution", 100, 0., 20.);
1130 TH1F* mbmH = new TH1F("mbmH", "MB Trigger Multiplicity Distribution", 100, 0., 8000.);
1131 TH1F* hdmH = new TH1F("hdmH", "Hard Trigger Multiplicity Distribution", 100, 0., 8000.);
1133 mbtH->SetXTitle("b [fm]");
1134 hdtH->SetXTitle("b [fm]");
1135 mbmH->SetXTitle("Multiplicity");
1136 hdmH->SetXTitle("Multiplicity");
1138 TCanvas *c0 = new TCanvas("c0","Trigger Simulation",400,10,600,700);
1140 TCanvas *c1 = new TCanvas("c1","Trigger Simulation",400,10,600,700);
1146 for (Int_t iev = 0; iev < n; iev++)
1149 GetRandom(b, p, mult);
1152 mbmH->Fill(mult, 1.);
1153 hdmH->Fill(mult, p);
1169 void AliFastGlauber::GetRandom(Float_t& b, Float_t& p, Float_t& mult)
1172 // Gives back a random impact parameter, hard trigger probability and multiplicity
1174 b = fgWSgeo->GetRandom();
1175 const Float_t kmu = fgWSN->Eval(b);
1176 p = 1.-TMath::Exp(-kmu);
1177 mult = 6000./fgWSN->Eval(1.) * kmu;
1180 void AliFastGlauber::GetRandom(Int_t& bin, Bool_t& hard)
1183 // Gives back a random impact parameter bin, and hard trigger decission
1185 const Float_t kb = fgWSgeo->GetRandom();
1186 const Float_t kmu = fgWSN->Eval(kb) * fSigmaHard;
1187 const Float_t kp = 1.-TMath::Exp(-kmu);
1190 } else if (kb < 8.6) {
1192 } else if (kb < 11.2) {
1194 } else if (kb < 13.2) {
1196 } else if (kb < 15.0) {
1202 const Float_t kr = gRandom->Rndm();
1203 if (kr < kp) hard = kTRUE;
1206 Double_t AliFastGlauber::GetRandomImpactParameter(Double_t bmin, Double_t bmax)
1209 // Gives back a random impact parameter in the range bmin .. bmax
1212 while(b < bmin || b > bmax)
1213 b = fgWSgeo->GetRandom();
1217 void AliFastGlauber::StoreFunctions() const
1220 // Store in file functions
1222 TFile* ff = new TFile(fName.Data(),"recreate");
1223 fgWStaa->Write("WStaa");
1224 fgWParticipants->Write("WParticipants");
1229 //=================== Added by A. Dainese 11/02/04 ===========================
1231 void AliFastGlauber::StoreAlmonds() const
1235 // 40 almonds for b = (0.25+k*0.5) fm (k=0->39)
1237 Char_t almondName[100];
1238 TFile* ff = new TFile(fName.Data(),"update");
1239 for(Int_t k=0; k<40; k++) {
1240 sprintf(almondName,"WAlmondFixedB%d",k);
1241 Double_t b = 0.25+k*0.5;
1242 Info("StoreAlmonds"," b = %f\n",b);
1243 fgWAlmond->SetParameter(0,b);
1244 fgWAlmond->Write(almondName);
1250 void AliFastGlauber::SetCentralityClass(Double_t xsecFrLow,Double_t xsecFrUp)
1253 // Set limits of centrality class as fractions
1254 // of the geomtrical cross section
1256 if(xsecFrLow>1. || xsecFrUp>1. || xsecFrLow>xsecFrUp) {
1257 Error("SetCentralityClass", "Please set 0 <= xsecFrLow <= xsecFrUp <= 1\n");
1261 Double_t bLow=0.,bUp=0.;
1263 const Double_t knorm=fgWSgeo->Integral(0.,100.);
1264 while(xsecFr<xsecFrLow) {
1265 xsecFr = fgWSgeo->Integral(0.,bLow)/knorm;
1269 while(xsecFr<xsecFrUp) {
1270 xsecFr = fgWSgeo->Integral(0.,bUp)/knorm;
1274 Info("SetCentralityClass", "Centrality class: %4.2f-%4.2f; %4.1f < b < %4.1f fm",
1275 xsecFrLow,xsecFrUp,bLow,bUp);
1276 fgWSbinary->SetRange(bLow,bUp);
1282 void AliFastGlauber::GetRandomBHard(Double_t& b)
1285 // Get random impact parameter according to distribution of
1286 // hard (binary) cross-section, in the range defined by the centrality class
1288 b = fgWSbinary->GetRandom();
1289 Int_t bin = 2*(Int_t)b;
1290 if( (b-(Int_t)b) > 0.5) bin++;
1291 fgWAlmondCurrent = fgWAlmondFixedB[bin];
1295 void AliFastGlauber::GetRandomXY(Double_t& x,Double_t& y)
1298 // Get random position of parton production point according to
1299 // product of thickness functions
1301 fgWAlmondCurrent->GetRandom2(x,y);
1305 void AliFastGlauber::GetRandomPhi(Double_t& phi)
1308 // Get random parton azimuthal propagation direction
1310 phi = 2.*TMath::Pi()*gRandom->Rndm();
1314 Double_t AliFastGlauber::CalculateLength(Double_t b,Double_t x0,Double_t y0,Double_t phi0)
1317 // Calculate path length for a parton with production point (x0,y0)
1318 // and propagation direction (ux=cos(phi0),uy=sin(phi0))
1319 // in a collision with impact parameter b
1322 // number of steps in l
1323 const Int_t kNp = 100;
1324 const Double_t kDl = fgBMax/Double_t(kNp);
1330 // ell = 2 * \int_0^\infty dl*l*(T_A*T_B)(x0+l*ux,y0+l*uy) /
1331 // \int_0^\infty dl*(T_A*T_B)(x0+l*ux,y0+l*uy)
1335 const Double_t kr0 = TMath::Sqrt(x0*x0 + y0*y0);
1336 const Int_t knps = Int_t ((fgBMax - kr0)/kDl) - 1;
1338 Double_t integral1 = 0.;
1339 Double_t integral2 = 0.;
1341 for (Int_t i = 0; i < knps; i++) {
1343 // Transform into target frame
1344 const Double_t kxx = x0 + l * TMath::Cos(phi0) + b / 2.;
1345 const Double_t kyy = y0 + l * TMath::Sin(phi0);
1346 const Double_t kphi = TMath::ATan2(kyy, kxx);
1347 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
1348 // Radius in projectile frame
1349 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + b*b - 2.*kr1*b*TMath::Cos(kphi));
1350 const Double_t kprodTATB = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
1352 integral1 += kprodTATB * l * kDl;
1353 integral2 += kprodTATB * kDl;
1359 ell = (2. * integral1 / integral2);
1361 } else if(fEllDef==2) {
1365 // ell = \int_0^\infty dl*
1366 // \Theta((T_A*T_B)(x0+l*ux,y0+l*uy)-0.5*(T_A*T_B)(0,0))
1370 const Double_t kr0 = TMath::Sqrt(x0*x0 + y0*y0);
1371 const Int_t knps = Int_t ((fgBMax - kr0)/kDl) - 1;
1372 const Double_t kprodTATBHalfMax = 0.5*fgWAlmondCurrent->Eval(0.,0.);
1375 Double_t integral = 0.;
1376 for (Int_t i = 0; i < knps; i++) {
1377 // Transform into target frame
1378 const Double_t kxx = x0 + l * TMath::Cos(phi0) + b / 2.;
1379 const Double_t kyy = y0 + l * TMath::Sin(phi0);
1380 const Double_t kphi = TMath::ATan2(kyy, kxx);
1381 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
1382 // Radius in projectile frame
1383 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + b*b - 2.*kr1*b*TMath::Cos(kphi));
1384 const Double_t kprodTATB = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
1385 if(kprodTATB>kprodTATBHalfMax) integral += kDl;
1388 Double_t ell = integral;
1391 Error("CalculateLength","Wrong length definition setting: %d !\n",fEllDef);
1396 void AliFastGlauber::GetLengthAndPhi(Double_t& ell,Double_t& phi,Double_t b)
1399 // Return length from random b, x0, y0, phi0
1402 Double_t x0,y0,phi0;
1403 if(b<0.) GetRandomBHard(b);
1407 ell = CalculateLength(b,x0,y0,phi0);
1411 void AliFastGlauber::GetLength(Double_t& ell,Double_t b)
1414 // Return length from random b, x0, y0, phi0
1417 GetLengthAndPhi(ell,phi,b);
1421 void AliFastGlauber::GetLengthsBackToBackAndPhi(Double_t& ell1,Double_t& ell2,Double_t &phi,Double_t b)
1424 // Return 2 lengths back to back from random b, x0, y0, phi0
1427 Double_t x0,y0,phi0;
1428 if(b<0.) GetRandomBHard(b);
1431 const Double_t kphi0plusPi = phi0+TMath::Pi();
1433 ell1 = CalculateLength(b,x0,y0,phi0);
1434 ell2 = CalculateLength(b,x0,y0,kphi0plusPi);
1438 void AliFastGlauber::GetLengthsBackToBack(Double_t& ell1,Double_t& ell2,
1442 // Return 2 lengths back to back from random b, x0, y0, phi0
1445 GetLengthsBackToBackAndPhi(ell1,ell2,phi,b);
1449 void AliFastGlauber::GetLengthsForPythia(Int_t n,Double_t* phi,Double_t* ell, Double_t b)
1452 // Returns lenghts for n partons with azimuthal angles phi[n]
1453 // from random b, x0, y0
1456 if(b < 0.) GetRandomBHard(b);
1458 for(Int_t i = 0; i< n; i++) ell[i] = CalculateLength(b,x0,y0,phi[i]);
1462 void AliFastGlauber::PlotBDistr(Int_t n)
1465 // Plot distribution of n impact parameters
1468 TH1F *hB = new TH1F("hB","dN/db",100,0,fgBMax);
1469 hB->SetXTitle("b [fm]");
1470 hB->SetYTitle("dN/db [a.u.]");
1471 hB->SetFillColor(3);
1472 for(Int_t i=0; i<n; i++) {
1476 TCanvas *cB = new TCanvas("cB","Impact parameter distribution",0,0,500,500);
1482 void AliFastGlauber::PlotLengthDistr(Int_t n,Bool_t save,const char *fname)
1485 // Plot length distribution
1488 TH1F *hEll = new TH1F("hEll","Length distribution",64,-0.5,15);
1489 hEll->SetXTitle("Transverse path length, L [fm]");
1490 hEll->SetYTitle("Probability");
1491 hEll->SetFillColor(2);
1492 for(Int_t i=0; i<n; i++) {
1496 hEll->Scale(1/(Double_t)n);
1497 TCanvas *cL = new TCanvas("cL","Length distribution",0,0,500,500);
1502 TFile *f = new TFile(fname,"recreate");
1509 void AliFastGlauber::PlotLengthB2BDistr(Int_t n,Bool_t save,const char *fname)
1512 // Plot lengths back-to-back distributions
1515 TH2F *hElls = new TH2F("hElls","Lengths back-to-back",100,0,15,100,0,15);
1516 hElls->SetXTitle("Transverse path length, L [fm]");
1517 hElls->SetYTitle("Transverse path length, L [fm]");
1518 for(Int_t i=0; i<n; i++) {
1519 GetLengthsBackToBack(ell1,ell2);
1520 hElls->Fill(ell1,ell2);
1522 hElls->Scale(1/(Double_t)n);
1523 TCanvas *cLs = new TCanvas("cLs","Length back-to-back distribution",0,0,500,500);
1524 gStyle->SetPalette(1,0);
1526 hElls->Draw("col,Z");
1528 TFile *f = new TFile(fname,"recreate");
1535 void AliFastGlauber::PlotAlmonds() const
1538 // Plot almonds for some impact parameters
1540 TCanvas *c = new TCanvas("c","Almonds",0,0,500,500);
1541 gStyle->SetPalette(1,0);
1544 fgWAlmondFixedB[0]->Draw("cont1");
1546 fgWAlmondFixedB[10]->Draw("cont1");
1548 fgWAlmondFixedB[20]->Draw("cont1");
1550 fgWAlmondFixedB[30]->Draw("cont1");
1554 //=================== Added by A. Dainese 05/03/04 ===========================
1556 void AliFastGlauber::CalculateI0I1(Double_t& integral0,Double_t& integral1,
1557 Double_t b,Double_t x0,Double_t y0,
1558 Double_t phi0,Double_t ellCut) const
1561 // Calculate integrals:
1562 // integral0 = \int_0^ellCut dl*(T_A*T_B)(x0+l*ux,y0+l*uy)
1563 // integral1 = \int_0^ellCut dl*l*(T_A*T_B)(x0+l*ux,y0+l*uy)
1565 // for a parton with production point (x0,y0)
1566 // and propagation direction (ux=cos(phi0),uy=sin(phi0))
1567 // in a collision with impact parameter b
1570 // number of steps in l
1571 const Int_t kNp = 100;
1572 const Double_t kDl = fgBMax/Double_t(kNp);
1575 const Double_t kr0 = TMath::Sqrt(x0 * x0 + y0 * y0);
1576 const Int_t knps = Int_t ((fgBMax - kr0)/kDl) - 1;
1583 while((i < knps) && (l < ellCut)) {
1584 // Transform into target frame
1585 const Double_t kxx = x0 + l * TMath::Cos(phi0) + b / 2.;
1586 const Double_t kyy = y0 + l * TMath::Sin(phi0);
1587 const Double_t kphi = TMath::ATan2(kyy, kxx);
1588 const Double_t kr1 = TMath::Sqrt(kxx*kxx + kyy*kyy);
1589 // Radius in projectile frame
1590 const Double_t kr2 = TMath::Sqrt(kr1*kr1 + b*b - 2.*kr1*b*TMath::Cos(kphi));
1591 const Double_t kprodTATB = fgWSta->Eval(kr1) * fgWSta->Eval(kr2);
1592 integral0 += kprodTATB * kDl;
1593 integral1 += kprodTATB * l * kDl;
1600 void AliFastGlauber::GetI0I1AndPhi(Double_t& integral0,Double_t& integral1,
1602 Double_t ellCut,Double_t b)
1605 // Return I0 and I1 from random b, x0, y0, phi0
1608 Double_t x0,y0,phi0;
1609 if(b<0.) GetRandomBHard(b);
1613 CalculateI0I1(integral0,integral1,b,x0,y0,phi0,ellCut);
1617 void AliFastGlauber::GetI0I1(Double_t& integral0,Double_t& integral1,
1618 Double_t ellCut,Double_t b)
1621 // Return I0 and I1 from random b, x0, y0, phi0
1624 GetI0I1AndPhi(integral0,integral1,phi,ellCut,b);
1628 void AliFastGlauber::GetI0I1BackToBackAndPhi(Double_t& integral01,Double_t& integral11,
1629 Double_t& integral02,Double_t& integral12,
1631 Double_t ellCut,Double_t b)
1634 // Return 2 pairs of I0 and I1 back to back from random b, x0, y0, phi0
1637 Double_t x0,y0,phi0;
1638 if(b<0.) GetRandomBHard(b);
1642 const Double_t kphi0plusPi = phi0+TMath::Pi();
1643 CalculateI0I1(integral01,integral11,b,x0,y0,phi0,ellCut);
1644 CalculateI0I1(integral02,integral12,b,x0,y0,kphi0plusPi,ellCut);
1648 void AliFastGlauber::GetI0I1BackToBackAndPhiAndXY(Double_t& integral01,Double_t& integral11,
1649 Double_t& integral02,Double_t& integral12,
1650 Double_t& phi,Double_t &x,Double_t &y,
1651 Double_t ellCut,Double_t b)
1654 // Return 2 pairs of I0 and I1 back to back from random b, x0, y0, phi0
1657 Double_t x0,y0,phi0;
1658 if(b<0.) GetRandomBHard(b);
1661 phi = phi0; x=x0; y=y0;
1662 const Double_t kphi0plusPi = phi0+TMath::Pi();
1663 CalculateI0I1(integral01,integral11,b,x0,y0,phi0,ellCut);
1664 CalculateI0I1(integral02,integral12,b,x0,y0,kphi0plusPi,ellCut);
1668 void AliFastGlauber::GetI0I1BackToBack(Double_t& integral01,Double_t& integral11,
1669 Double_t& integral02,Double_t& integral12,
1670 Double_t ellCut,Double_t b)
1673 // Return 2 pairs of I0 and I1 back to back from random b, x0, y0, phi0
1676 GetI0I1BackToBackAndPhi(integral01,integral11,integral02,integral12,
1681 void AliFastGlauber::GetI0I1ForPythia(Int_t n,Double_t* phi,
1682 Double_t* integral0,Double_t* integral1,
1683 Double_t ellCut,Double_t b)
1686 // Returns I0 and I1 pairs for n partons with azimuthal angles phi[n]
1687 // from random b, x0, y0
1690 if(b<0.) GetRandomBHard(b);
1692 for(Int_t i=0; i<n; i++)
1693 CalculateI0I1(integral0[i],integral1[i],b,x0,y0,phi[i],ellCut);
1697 void AliFastGlauber::GetI0I1ForPythiaAndXY(Int_t n,Double_t* phi,
1698 Double_t* integral0,Double_t* integral1,
1699 Double_t &x,Double_t& y,
1700 Double_t ellCut,Double_t b)
1703 // Returns I0 and I1 pairs for n partons with azimuthal angles phi[n]
1704 // from random b, x0, y0 and return x0,y0
1707 if(b<0.) GetRandomBHard(b);
1709 for(Int_t i=0; i<n; i++)
1710 CalculateI0I1(integral0[i],integral1[i],b,x0,y0,phi[i],ellCut);
1716 void AliFastGlauber::PlotI0I1Distr(Int_t n,Double_t ellCut,
1717 Bool_t save,const char *fname)
1720 // Plot I0-I1 distribution
1723 TH2F *hI0I1s = new TH2F("hI0I1s","I_{0} versus I_{1}",1000,0,0.001,1000,0,0.01);
1724 hI0I1s->SetXTitle("I_{0} [fm^{-3}]");
1725 hI0I1s->SetYTitle("I_{1} [fm^{-2}]");
1727 TH1F *hI0 = new TH1F("hI0","I_{0} = #hat{q}L / k",
1729 hI0->SetXTitle("I_{0} [fm^{-3}]");
1730 hI0->SetYTitle("Probability");
1731 hI0->SetFillColor(3);
1732 TH1F *hI1 = new TH1F("hI1","I_{1} = #omega_{c} / k",
1734 hI1->SetXTitle("I_{1} [fm^{-2}]");
1735 hI1->SetYTitle("Probability");
1736 hI1->SetFillColor(4);
1737 TH1F *h2 = new TH1F("h2","2 I_{1}^{2}/I_{0} = R / k",
1739 h2->SetXTitle("2 I_{1}^{2}/I_{0} [fm^{-1}]");
1740 h2->SetYTitle("Probability");
1741 h2->SetFillColor(2);
1742 TH1F *h3 = new TH1F("h3","2 I_{1}/I_{0} = L",
1744 h3->SetXTitle("2 I_{1}/I_{0} [fm]");
1745 h3->SetYTitle("Probability");
1746 h3->SetFillColor(5);
1747 TH1F *h4 = new TH1F("h4","I_{0}^{2}/(2 I_{1}) = #hat{q} / k",
1749 h4->SetXTitle("I_{0}^{2}/(2 I_{1}) [fm^{-4}]");
1750 h4->SetYTitle("Probability");
1751 h4->SetFillColor(7);
1753 for(Int_t i=0; i<n; i++) {
1754 GetI0I1(i0,i1,ellCut);
1755 hI0I1s->Fill(i0,i1);
1758 h2->Fill(2.*i1*i1/i0);
1760 h4->Fill(i0*i0/2./i1);
1762 hI0->Scale(1/(Double_t)n);
1763 hI1->Scale(1/(Double_t)n);
1764 h2->Scale(1/(Double_t)n);
1765 h3->Scale(1/(Double_t)n);
1766 h4->Scale(1/(Double_t)n);
1767 hI0I1s->Scale(1/(Double_t)n);
1769 TCanvas *cI0I1 = new TCanvas("cI0I1","I0 and I1",0,0,900,700);
1782 gStyle->SetPalette(1,0);
1783 hI0I1s->Draw("col,Z");
1786 TFile *f = new TFile(fname,"recreate");
1798 void AliFastGlauber::PlotI0I1B2BDistr(Int_t n,Double_t ellCut,
1799 Bool_t save,const char *fname)
1802 // Plot I0-I1 back-to-back distributions
1804 Double_t i01,i11,i02,i12;
1805 TH2F *hI0s = new TH2F("hI0s","I_{0}'s back-to-back",100,0,100,100,0,100);
1806 hI0s->SetXTitle("I_{0} [fm^{-3}]");
1807 hI0s->SetYTitle("I_{0} [fm^{-3}]");
1808 TH2F *hI1s = new TH2F("hI1s","I_{1}'s back-to-back",100,0,100,100,0,100);
1809 hI1s->SetXTitle("I_{1} [fm^{-2}]");
1810 hI1s->SetYTitle("I_{1} [fm^{-2}]");
1812 for(Int_t i=0; i<n; i++) {
1813 GetI0I1BackToBack(i01,i11,i02,i12,ellCut);
1814 hI0s->Fill(i01,i02);
1815 hI1s->Fill(i11,i12);
1817 hI0s->Scale(1/(Double_t)n);
1818 hI1s->Scale(1/(Double_t)n);
1820 TCanvas *cI0I1s = new TCanvas("cI0I1s","I0 and I1 back-to-back distributions",0,0,800,400);
1821 gStyle->SetPalette(1,0);
1822 cI0I1s->Divide(2,1);
1824 hI0s->Draw("col,Z");
1826 hI1s->Draw("col,Z");
1829 TFile *f = new TFile(fname,"recreate");
1837 AliFastGlauber& AliFastGlauber::operator=(const AliFastGlauber& rhs)
1839 // Assignment operator
1844 void AliFastGlauber::Copy(TObject&) const
1849 Fatal("Copy","Not implemented!\n");