2 /**************************************************************************
3 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
5 * Author: The ALICE Off-line Project. *
6 * Contributors are mentioned in the code where appropriate. *
8 * Permission to use, copy, modify and distribute this software and its *
9 * documentation strictly for non-commercial purposes is hereby granted *
10 * without fee, provided that the above copyright notice appears in all *
11 * copies and that both the copyright notice and this permission notice *
12 * appear in the supporting documentation. The authors make no claims *
13 * about the suitability of this software for any purpose. It is *
14 * provided "as is" without express or implied warranty. *
15 **************************************************************************/
17 /* $Id: AliPythia.cxx,v 1.40 2007/10/09 08:43:24 morsch Exp $ */
19 #include "AliPythia6.h"
21 #include "AliPythiaRndm.h"
22 #include "AliFastGlauber.h"
23 #include "AliQuenchingWeights.h"
26 #include "TParticle.h"
27 #include "PyquenCommon.h"
32 # define pyclus pyclus_
33 # define pycell pycell_
34 # define pyshow pyshow_
35 # define pyrobo pyrobo_
36 # define pyquen pyquen_
37 # define pyevnw pyevnw_
40 # define pyclus PYCLUS
41 # define pycell PYCELL
42 # define pyrobo PYROBO
43 # define pyquen PYQUEN
44 # define pyevnw PYEVNW
45 # define type_of_call _stdcall
48 extern "C" void type_of_call pyclus(Int_t & );
49 extern "C" void type_of_call pycell(Int_t & );
50 extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
51 extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
52 extern "C" void type_of_call pyquen(Double_t &, Int_t &, Double_t &);
53 extern "C" void type_of_call pyevnw();
56 //_____________________________________________________________________________
58 AliPythia6* AliPythia6::fgAliPythia=NULL;
60 AliPythia6::AliPythia6():
73 // Default Constructor
76 if (!AliPythiaRndm::GetPythiaRandom())
77 AliPythiaRndm::SetPythiaRandom(GetRandom());
79 fQuenchingWeights = 0;
82 AliPythia6::AliPythia6(const AliPythia6& pythia):
99 void AliPythia6::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc)
101 // Initialise the process to generate
102 if (!AliPythiaRndm::GetPythiaRandom())
103 AliPythiaRndm::SetPythiaRandom(GetRandom());
107 fStrucFunc = strucfunc;
108 //...Switch off decay of pi0, K0S, Lambda, Sigma+-, Xi0-, Omega-.
109 SetMDCY(Pycomp(111) ,1,0);
110 SetMDCY(Pycomp(310) ,1,0);
111 SetMDCY(Pycomp(3122),1,0);
112 SetMDCY(Pycomp(3112),1,0);
113 SetMDCY(Pycomp(3212),1,0);
114 SetMDCY(Pycomp(3222),1,0);
115 SetMDCY(Pycomp(3312),1,0);
116 SetMDCY(Pycomp(3322),1,0);
117 SetMDCY(Pycomp(3334),1,0);
118 // Select structure function
120 SetMSTP(51,AliStructFuncType::PDFsetIndex(strucfunc));
121 // Particles produced in string fragmentation point directly to either of the two endpoints
122 // of the string (depending in the side they were generated from).
126 // Pythia initialisation for selected processes//
130 for (Int_t i=1; i<= 200; i++) {
133 // select charm production
136 case kPyOldUEQ2ordered: //Old underlying events with Q2 ordered QCD processes
137 // Multiple interactions on.
139 // Double Gaussian matter distribution.
145 // Reference energy for pT0 and energy rescaling pace.
148 // String drawing almost completely minimizes string length.
151 // ISR and FSR activity.
157 case kPyOldUEQ2ordered2:
158 // Old underlying events with Q2 ordered QCD processes
159 // Multiple interactions on.
161 // Double Gaussian matter distribution.
167 // Reference energy for pT0 and energy rescaling pace.
169 SetPARP(90,0.16); // here is the difference with kPyOldUEQ2ordered
170 // String drawing almost completely minimizes string length.
173 // ISR and FSR activity.
180 // Old production mechanism: Old Popcorn
183 // (D=2) Like MSTJ(12)=2 but added prod ofthe 1er rank baryon
185 // (D=1)see can be used to form baryons (BARYON JUNCTION)
191 // heavy quark masses
221 case kPyCharmUnforced:
230 case kPyBeautyUnforced:
240 // Minimum Bias pp-Collisions
243 // select Pythia min. bias model
245 SetMSUB(92,1); // single diffraction AB-->XB
246 SetMSUB(93,1); // single diffraction AB-->AX
247 SetMSUB(94,1); // double diffraction
248 SetMSUB(95,1); // low pt production
253 case kPyMbWithDirectPhoton:
254 // Minimum Bias pp-Collisions with direct photon processes added
257 // select Pythia min. bias model
259 SetMSUB(92,1); // single diffraction AB-->XB
260 SetMSUB(93,1); // single diffraction AB-->AX
261 SetMSUB(94,1); // double diffraction
262 SetMSUB(95,1); // low pt production
275 // Minimum Bias pp-Collisions
278 // select Pythia min. bias model
280 SetMSUB(92,1); // single diffraction AB-->XB
281 SetMSUB(93,1); // single diffraction AB-->AX
282 SetMSUB(94,1); // double diffraction
283 SetMSUB(95,1); // low pt production
287 // Les Houches Working Group 05 Minimum Bias pp-Collisions: hep-ph/0604120
288 // -> Pythia 6.3 or above is needed
291 SetMSUB(92,1); // single diffraction AB-->XB
292 SetMSUB(93,1); // single diffraction AB-->AX
293 SetMSUB(94,1); // double diffraction
294 SetMSUB(95,1); // low pt production
295 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ6ll));
299 SetMSTP(81,1); // Multiple Interactions ON
300 SetMSTP(82,4); // Double Gaussian Model
303 SetPARP(82,2.3); // [GeV] PT_min at Ref. energy
304 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
305 SetPARP(84,0.5); // Core radius
306 SetPARP(85,0.9); // Regulates gluon prod. mechanism
307 SetPARP(90,0.2); // 2*epsilon (exponent in power law)
311 // Minimum Bias pp-Collisions
314 // select Pythia min. bias model
316 SetMSUB(95,1); // low pt production
323 SetMSTP(91,1);// Width (1=gaussian) primordial kT dist. inside hadrons
324 SetPARP(91,1.); // <kT^2> = PARP(91,1.)^2
325 SetPARP(93,5.); // Upper cut-off
327 SetPMAS(4,1,1.2); // Charm quark mass
328 SetPMAS(5,1,4.78); // Beauty quark mass
329 SetPARP(71,4.); // Defaut value
338 // Pythia Tune A (CDF)
340 SetPARP(67,2.5); // Regulates Initial State Radiation (value from best fit to D0 dijet analysis)
341 SetMSTP(82,4); // Double Gaussian Model
342 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
343 SetPARP(84,0.4); // Core radius
344 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
345 SetPARP(86,0.95); // Regulates gluon prod. mechanism
346 SetPARP(89,1800.); // [GeV] Ref. energy
347 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
352 case kPyCharmPbPbMNR:
354 case kPyDPlusPbPbMNR:
355 case kPyDPlusStrangePbPbMNR:
356 // Tuning of Pythia parameters aimed to get a resonable agreement
357 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
358 // c-cbar single inclusive and double differential distributions.
359 // This parameter settings are meant to work with Pb-Pb collisions
360 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
361 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
362 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
374 case kPyDPlusStrangepPbMNR:
375 // Tuning of Pythia parameters aimed to get a resonable agreement
376 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
377 // c-cbar single inclusive and double differential distributions.
378 // This parameter settings are meant to work with p-Pb collisions
379 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
380 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
381 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
394 case kPyDPlusStrangeppMNR:
395 // Tuning of Pythia parameters aimed to get a resonable agreement
396 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
397 // c-cbar single inclusive and double differential distributions.
398 // This parameter settings are meant to work with pp collisions
399 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
400 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
401 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
411 case kPyCharmppMNRwmi:
412 // Tuning of Pythia parameters aimed to get a resonable agreement
413 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
414 // c-cbar single inclusive and double differential distributions.
415 // This parameter settings are meant to work with pp collisions
416 // and with kCTEQ5L PDFs.
417 // Added multiple interactions according to ATLAS tune settings.
418 // To get a "reasonable" agreement with MNR results, events have to be
419 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
421 // To get a "perfect" agreement with MNR results, events have to be
422 // generated in four ptHard bins with the following relative
438 case kPyBeautyPbPbMNR:
439 // Tuning of Pythia parameters aimed to get a resonable agreement
440 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
441 // b-bbar single inclusive and double differential distributions.
442 // This parameter settings are meant to work with Pb-Pb collisions
443 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
444 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
445 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
457 case kPyBeautypPbMNR:
458 // Tuning of Pythia parameters aimed to get a resonable agreement
459 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
460 // b-bbar single inclusive and double differential distributions.
461 // This parameter settings are meant to work with p-Pb collisions
462 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
463 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
464 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
477 // Tuning of Pythia parameters aimed to get a resonable agreement
478 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
479 // b-bbar single inclusive and double differential distributions.
480 // This parameter settings are meant to work with pp collisions
481 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
482 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
483 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
497 case kPyBeautyppMNRwmi:
498 // Tuning of Pythia parameters aimed to get a resonable agreement
499 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
500 // b-bbar single inclusive and double differential distributions.
501 // This parameter settings are meant to work with pp collisions
502 // and with kCTEQ5L PDFs.
503 // Added multiple interactions according to ATLAS tune settings.
504 // To get a "reasonable" agreement with MNR results, events have to be
505 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
507 // To get a "perfect" agreement with MNR results, events have to be
508 // generated in four ptHard bins with the following relative
531 //Inclusive production of W+/-
537 // //f fbar -> gamma W+
544 // Initial/final parton shower on (Pythia default)
545 // With parton showers on we are generating "W inclusive process"
546 SetMSTP(61,1); //Initial QCD & QED showers on
547 SetMSTP(71,1); //Final QCD & QED showers on
553 //Inclusive production of Z
558 // // f fbar -> g Z/gamma
560 // // f fbar -> gamma Z/gamma
562 // // f g -> f Z/gamma
564 // // f gamma -> f Z/gamma
567 //only Z included, not gamma
570 // Initial/final parton shower on (Pythia default)
571 // With parton showers on we are generating "Z inclusive process"
572 SetMSTP(61,1); //Initial QCD & QED showers on
573 SetMSTP(71,1); //Final QCD & QED showers on
580 SetMSTP(41,1); // all resonance decays switched on
581 Initialize("CMS","p","p",fEcms);
585 Int_t AliPythia6::CheckedLuComp(Int_t kf)
587 // Check Lund particle code (for debugging)
592 void AliPythia6::SetNuclei(Int_t a1, Int_t a2)
594 // Treat protons as inside nuclei with mass numbers a1 and a2
595 // The MSTP array in the PYPARS common block is used to enable and
596 // select the nuclear structure functions.
597 // MSTP(52) : (D=1) choice of proton and nuclear structure-function library
598 // =1: internal PYTHIA acording to MSTP(51)
599 // =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
600 // If the following mass number both not equal zero, nuclear corrections of the stf are used.
601 // MSTP(192) : Mass number of nucleus side 1
602 // MSTP(193) : Mass number of nucleus side 2
609 AliPythia6* AliPythia6::Instance()
611 // Set random number generator
615 fgAliPythia = new AliPythia6();
620 void AliPythia6::PrintParticles()
622 // Print list of particl properties
624 char* name = new char[16];
625 for (Int_t kf=0; kf<1000000; kf++) {
626 for (Int_t c = 1; c > -2; c-=2) {
627 Int_t kc = Pycomp(c*kf);
629 Float_t mass = GetPMAS(kc,1);
630 Float_t width = GetPMAS(kc,2);
631 Float_t tau = GetPMAS(kc,4);
637 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
638 c*kf, name, mass, width, tau);
642 printf("\n Number of particles %d \n \n", np);
645 void AliPythia6::ResetDecayTable()
647 // Set default values for pythia decay switches
649 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
650 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
653 void AliPythia6::SetDecayTable()
655 // Set default values for pythia decay switches
658 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
659 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
662 void AliPythia6::Pyclus(Int_t& njet)
664 // Call Pythia clustering algorithm
669 void AliPythia6::Pycell(Int_t& njet)
671 // Call Pythia jet reconstruction algorithm
676 void AliPythia6::GetJet(Int_t i, Float_t& px, Float_t& py, Float_t& pz, Float_t& e)
680 px = GetPyjets()->P[0][n+i];
681 py = GetPyjets()->P[1][n+i];
682 pz = GetPyjets()->P[2][n+i];
683 e = GetPyjets()->P[3][n+i];
686 void AliPythia6::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
688 // Call Pythia showering
690 pyshow(ip1, ip2, qmax);
693 void AliPythia6::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
695 pyrobo(imi, ima, the, phi, bex, bey, bez);
700 void AliPythia6::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod, Float_t zmax, Int_t ngmax)
703 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
704 // (2) The nuclear geometry using the Glauber Model
707 fGlauber = AliFastGlauber::Instance();
709 fGlauber->SetCentralityClass(cMin, cMax);
711 fQuenchingWeights = new AliQuenchingWeights();
712 fQuenchingWeights->InitMult();
713 fQuenchingWeights->SetK(k);
714 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
721 void AliPythia6::Quench()
725 // Simple Jet Quenching routine:
726 // =============================
727 // The jet formed by all final state partons radiated by the parton created
728 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
729 // the initial parton reference frame:
730 // (E + p_z)new = (1-z) (E + p_z)old
735 // The lost momentum is first balanced by one gluon with virtuality > 0.
736 // Subsequently the gluon splits to yield two gluons with E = p.
740 static Float_t eMean = 0.;
741 static Int_t icall = 0;
746 Int_t klast[4] = {-1, -1, -1, -1};
748 Int_t numpart = fPyjets->N;
749 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
750 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
758 // Sore information about Primary partons
761 // 0, 1 partons from hard scattering
762 // 2, 3 partons from initial state radiation
764 for (Int_t i = 2; i <= 7; i++) {
766 // Skip gluons that participate in hard scattering
767 if (i == 4 || i == 5) continue;
768 // Gluons from hard Scattering
769 if (i == 6 || i == 7) {
771 pxq[j] = fPyjets->P[0][i];
772 pyq[j] = fPyjets->P[1][i];
773 pzq[j] = fPyjets->P[2][i];
774 eq[j] = fPyjets->P[3][i];
775 mq[j] = fPyjets->P[4][i];
777 // Gluons from initial state radiation
779 // Obtain 4-momentum vector from difference between original parton and parton after gluon
780 // radiation. Energy is calculated independently because initial state radition does not
781 // conserve strictly momentum and energy for each partonic system independently.
783 // Not very clean. Should be improved !
787 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
788 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
789 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
790 mq[j] = fPyjets->P[4][i];
791 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
794 // Calculate some kinematic variables
796 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
797 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
798 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
799 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
800 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
801 qPdg[j] = fPyjets->K[1][i];
807 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
809 for (Int_t j = 0; j < 4; j++) {
811 // Quench only central jets and with E > 10.
815 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
816 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
818 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
821 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
827 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
828 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
830 // Fractional energy loss
831 fZQuench[j] = eloss / eq[j];
833 // Avoid complete loss
835 if (fZQuench[j] > fZmax) fZQuench[j] = fZmax;
837 // Some debug printing
840 // printf("Initial parton # %3d, Type %3d Energy %10.3f Phi %10.3f Length %10.3f Loss %10.3f Kick %10.3f Mean: %10.3f %10.3f\n",
841 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
843 // fZQuench[j] = 0.8;
844 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
847 quenched[j] = (fZQuench[j] > 0.01);
852 Double_t pNew[1000][4];
859 for (Int_t isys = 0; isys < 4; isys++) {
860 // Skip to next system if not quenched.
861 if (!quenched[isys]) continue;
863 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
864 if (nGluon[isys] > fNGmax) nGluon[isys] = fNGmax;
865 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
866 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
872 Double_t pg[4] = {0., 0., 0., 0.};
875 // Loop on radiation events
877 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
880 for (Int_t k = 0; k < 4; k++)
887 for (Int_t i = 0; i < numpart; i++)
889 imo = fPyjets->K[2][i];
890 kst = fPyjets->K[0][i];
891 pdg = fPyjets->K[1][i];
895 // Quarks and gluons only
896 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
897 // Particles from hard scattering only
899 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
900 Int_t imom = imo % 1000;
901 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
902 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
905 // Skip comment lines
906 if (kst != 1 && kst != 2) continue;
909 px = fPyjets->P[0][i];
910 py = fPyjets->P[1][i];
911 pz = fPyjets->P[2][i];
912 e = fPyjets->P[3][i];
913 m = fPyjets->P[4][i];
914 pt = TMath::Sqrt(px * px + py * py);
915 p = TMath::Sqrt(px * px + py * py + pz * pz);
916 phi = TMath::Pi() + TMath::ATan2(-py, -px);
917 theta = TMath::ATan2(pt, pz);
920 // Save 4-momentum sum for balancing
931 // Fractional energy loss
932 Double_t z = zquench[index];
935 // Don't fully quench radiated gluons
938 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
943 // printf("z: %d %f\n", imo, z);
950 // Transform into frame in which initial parton is along z-axis
952 TVector3 v(px, py, pz);
953 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
954 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
956 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
957 Double_t mt2 = jt * jt + m * m;
960 // Kinematic limit on z
962 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
964 // Change light-cone kinematics rel. to initial parton
966 Double_t eppzOld = e + pl;
967 Double_t empzOld = e - pl;
969 Double_t eppzNew = (1. - z) * eppzOld;
970 Double_t empzNew = empzOld - mt2 * z / eppzOld;
971 Double_t eNew = 0.5 * (eppzNew + empzNew);
972 Double_t plNew = 0.5 * (eppzNew - empzNew);
976 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
977 Double_t mt2New = eppzNew * empzNew;
978 if (mt2New < 1.e-8) mt2New = 0.;
980 if (m * m > mt2New) {
982 // This should not happen
984 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
987 jtNew = TMath::Sqrt(mt2New - m * m);
990 // If pT is to small (probably a leading massive particle) we scale only the energy
991 // This can cause negative masses of the radiated gluon
992 // Let's hope for the best ...
994 eNew = TMath::Sqrt(plNew * plNew + mt2);
998 // Calculate new px, py
1004 pxNew = jtNew / jt * pxs;
1005 pyNew = jtNew / jt * pys;
1008 // Double_t dpx = pxs - pxNew;
1009 // Double_t dpy = pys - pyNew;
1010 // Double_t dpz = pl - plNew;
1011 // Double_t de = e - eNew;
1012 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
1013 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
1014 // printf("New mass (2) %e %e \n", pxNew, pyNew);
1018 TVector3 w(pxNew, pyNew, plNew);
1019 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
1020 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
1022 p1[index][0] += pxNew;
1023 p1[index][1] += pyNew;
1024 p1[index][2] += plNew;
1025 p1[index][3] += eNew;
1027 // Updated 4-momentum vectors
1029 pNew[icount][0] = pxNew;
1030 pNew[icount][1] = pyNew;
1031 pNew[icount][2] = plNew;
1032 pNew[icount][3] = eNew;
1037 // Check if there was phase-space for quenching
1040 if (icount == 0) quenched[isys] = kFALSE;
1041 if (!quenched[isys]) break;
1043 for (Int_t j = 0; j < 4; j++)
1045 p2[isys][j] = p0[isys][j] - p1[isys][j];
1047 p2[isys][4] = p2[isys][3] * p2[isys][3] - p2[isys][0] * p2[isys][0] - p2[isys][1] * p2[isys][1] - p2[isys][2] * p2[isys][2];
1048 if (p2[isys][4] > 0.) {
1049 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
1052 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
1053 printf("4-Momentum: %10.3e %10.3e %10.3e %10.3e %10.3e \n", p2[isys][0], p2[isys][1], p2[isys][2], p2[isys][3], p2[isys][4]);
1054 if (p2[isys][4] < -0.01) {
1055 printf("Negative mass squared !\n");
1056 // Here we have to put the gluon back to mass shell
1057 // This will lead to a small energy imbalance
1059 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
1068 printf("zHeavy lowered to %f\n", zHeavy);
1069 if (zHeavy < 0.01) {
1070 printf("No success ! \n");
1072 quenched[isys] = kFALSE;
1076 } // iteration on z (while)
1078 // Update event record
1079 for (Int_t k = 0; k < icount; k++) {
1080 // printf("%6d %6d %10.3e %10.3e %10.3e %10.3e\n", k, kNew[k], pNew[k][0],pNew[k][1], pNew[k][2], pNew[k][3] );
1081 fPyjets->P[0][kNew[k]] = pNew[k][0];
1082 fPyjets->P[1][kNew[k]] = pNew[k][1];
1083 fPyjets->P[2][kNew[k]] = pNew[k][2];
1084 fPyjets->P[3][kNew[k]] = pNew[k][3];
1091 if (!quenched[isys]) continue;
1093 // Last parton from shower i
1094 Int_t in = klast[isys];
1096 // Continue if no parton in shower i selected
1097 if (in == -1) continue;
1099 // If this is the second initial parton and it is behind the first move pointer by previous ish
1100 if (isys == 1 && klast[1] > klast[0]) in += ish;
1105 // How many additional gluons will be generated
1107 if (p2[isys][4] > 0.05) ish = 2;
1109 // Position of gluons
1111 if (iglu == 0) igMin = iGlu;
1114 (fPyjets->N) += ish;
1117 fPyjets->P[0][iGlu] = p2[isys][0];
1118 fPyjets->P[1][iGlu] = p2[isys][1];
1119 fPyjets->P[2][iGlu] = p2[isys][2];
1120 fPyjets->P[3][iGlu] = p2[isys][3];
1121 fPyjets->P[4][iGlu] = p2[isys][4];
1123 fPyjets->K[0][iGlu] = 1;
1124 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1125 fPyjets->K[1][iGlu] = 21;
1126 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1127 fPyjets->K[3][iGlu] = -1;
1128 fPyjets->K[4][iGlu] = -1;
1130 pg[0] += p2[isys][0];
1131 pg[1] += p2[isys][1];
1132 pg[2] += p2[isys][2];
1133 pg[3] += p2[isys][3];
1136 // Split gluon in rest frame.
1138 Double_t bx = p2[isys][0] / p2[isys][3];
1139 Double_t by = p2[isys][1] / p2[isys][3];
1140 Double_t bz = p2[isys][2] / p2[isys][3];
1141 Double_t pst = p2[isys][4] / 2.;
1143 // Isotropic decay ????
1144 Double_t cost = 2. * gRandom->Rndm() - 1.;
1145 Double_t sint = TMath::Sqrt((1.-cost)*(1.+cost));
1146 Double_t phis = 2. * TMath::Pi() * gRandom->Rndm();
1148 Double_t pz1 = pst * cost;
1149 Double_t pz2 = -pst * cost;
1150 Double_t pt1 = pst * sint;
1151 Double_t pt2 = -pst * sint;
1152 Double_t px1 = pt1 * TMath::Cos(phis);
1153 Double_t py1 = pt1 * TMath::Sin(phis);
1154 Double_t px2 = pt2 * TMath::Cos(phis);
1155 Double_t py2 = pt2 * TMath::Sin(phis);
1157 fPyjets->P[0][iGlu] = px1;
1158 fPyjets->P[1][iGlu] = py1;
1159 fPyjets->P[2][iGlu] = pz1;
1160 fPyjets->P[3][iGlu] = pst;
1161 fPyjets->P[4][iGlu] = 0.;
1163 fPyjets->K[0][iGlu] = 1 ;
1164 fPyjets->K[1][iGlu] = 21;
1165 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1166 fPyjets->K[3][iGlu] = -1;
1167 fPyjets->K[4][iGlu] = -1;
1169 fPyjets->P[0][iGlu+1] = px2;
1170 fPyjets->P[1][iGlu+1] = py2;
1171 fPyjets->P[2][iGlu+1] = pz2;
1172 fPyjets->P[3][iGlu+1] = pst;
1173 fPyjets->P[4][iGlu+1] = 0.;
1175 fPyjets->K[0][iGlu+1] = 1;
1176 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1177 fPyjets->K[1][iGlu+1] = 21;
1178 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1179 fPyjets->K[3][iGlu+1] = -1;
1180 fPyjets->K[4][iGlu+1] = -1;
1186 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1189 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1190 Double_t px, py, pz;
1191 px = fPyjets->P[0][ig];
1192 py = fPyjets->P[1][ig];
1193 pz = fPyjets->P[2][ig];
1194 TVector3 v(px, py, pz);
1195 v.RotateZ(-phiq[isys]);
1196 v.RotateY(-thetaq[isys]);
1197 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1198 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1199 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1200 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1201 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1202 pxs += jtKick * TMath::Cos(phiKick);
1203 pys += jtKick * TMath::Sin(phiKick);
1204 TVector3 w(pxs, pys, pzs);
1205 w.RotateY(thetaq[isys]);
1206 w.RotateZ(phiq[isys]);
1207 fPyjets->P[0][ig] = w.X();
1208 fPyjets->P[1][ig] = w.Y();
1209 fPyjets->P[2][ig] = w.Z();
1210 fPyjets->P[2][ig] = w.Mag();
1216 // Check energy conservation
1220 Double_t es = 14000.;
1222 for (Int_t i = 0; i < numpart; i++)
1224 kst = fPyjets->K[0][i];
1225 if (kst != 1 && kst != 2) continue;
1226 pxs += fPyjets->P[0][i];
1227 pys += fPyjets->P[1][i];
1228 pzs += fPyjets->P[2][i];
1229 es -= fPyjets->P[3][i];
1231 if (TMath::Abs(pxs) > 1.e-2 ||
1232 TMath::Abs(pys) > 1.e-2 ||
1233 TMath::Abs(pzs) > 1.e-1) {
1234 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1235 // Fatal("Quench()", "4-Momentum non-conservation");
1238 } // end quenching loop (systems)
1240 for (Int_t i = 0; i < numpart; i++)
1242 imo = fPyjets->K[2][i];
1244 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1251 void AliPythia6::Pyquen(Double_t a, Int_t ibf, Double_t b)
1253 // Igor Lokthine's quenching routine
1254 // http://lokhtin.web.cern.ch/lokhtin/pyquen/pyquen.txt
1259 void AliPythia6::SetPyquenParameters(Double_t t0, Double_t tau0, Int_t nf, Int_t iengl, Int_t iangl)
1261 // Set the parameters for the PYQUEN package.
1262 // See comments in PyquenCommon.h
1268 PYQPAR.iengl = iengl;
1269 PYQPAR.iangl = iangl;
1272 void AliPythia6::LoadEvent(AliStack* stack, Int_t flag, Int_t reHadr)
1275 // Load event into Pythia Common Block
1278 Int_t npart = stack -> GetNprimary();
1282 GetPyjets()->N = npart;
1284 n0 = GetPyjets()->N;
1285 GetPyjets()->N = n0 + npart;
1289 for (Int_t part = 0; part < npart; part++) {
1290 TParticle *mPart = stack->Particle(part);
1292 Int_t kf = mPart->GetPdgCode();
1293 Int_t ks = mPart->GetStatusCode();
1294 Int_t idf = mPart->GetFirstDaughter();
1295 Int_t idl = mPart->GetLastDaughter();
1298 if (ks == 11 || ks == 12) {
1305 Float_t px = mPart->Px();
1306 Float_t py = mPart->Py();
1307 Float_t pz = mPart->Pz();
1308 Float_t e = mPart->Energy();
1309 Float_t m = mPart->GetCalcMass();
1312 (GetPyjets())->P[0][part+n0] = px;
1313 (GetPyjets())->P[1][part+n0] = py;
1314 (GetPyjets())->P[2][part+n0] = pz;
1315 (GetPyjets())->P[3][part+n0] = e;
1316 (GetPyjets())->P[4][part+n0] = m;
1318 (GetPyjets())->K[1][part+n0] = kf;
1319 (GetPyjets())->K[0][part+n0] = ks;
1320 (GetPyjets())->K[3][part+n0] = idf + 1;
1321 (GetPyjets())->K[4][part+n0] = idl + 1;
1322 (GetPyjets())->K[2][part+n0] = mPart->GetFirstMother() + 1;
1327 void AliPythia6::Pyevnw()
1329 // New multiple interaction scenario
1333 void AliPythia6::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1335 // Return event specific quenching parameters
1338 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];
1342 void AliPythia6::ConfigHeavyFlavor()
1345 // Default configuration for Heavy Flavor production
1347 // All QCD processes
1351 // No multiple interactions
1355 // Initial/final parton shower on (Pythia default)
1359 // 2nd order alpha_s
1367 void AliPythia6::AtlasTuning()
1370 // Configuration for the ATLAS tuning
1371 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ5L));
1372 SetMSTP(81,1); // Multiple Interactions ON
1373 SetMSTP(82,4); // Double Gaussian Model
1374 SetPARP(81,1.9); // Min. pt for multiple interactions (default in 6.2-14)
1375 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
1376 SetPARP(89,1000.); // [GeV] Ref. energy
1377 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
1378 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
1379 SetPARP(84,0.5); // Core radius
1380 SetPARP(85,0.33); // Regulates gluon prod. mechanism
1381 SetPARP(86,0.66); // Regulates gluon prod. mechanism
1382 SetPARP(67,1); // Regulates Initial State Radiation
1385 void AliPythia6::SetPtHardRange(Float_t ptmin, Float_t ptmax)
1387 // Set the pt hard range
1392 void AliPythia6::SetYHardRange(Float_t ymin, Float_t ymax)
1394 // Set the y hard range
1400 void AliPythia6::SetFragmentation(Int_t flag)
1402 // Switch fragmentation on/off
1406 void AliPythia6::SetInitialAndFinalStateRadiation(Int_t flag1, Int_t flag2)
1408 // initial state radiation
1410 // final state radiation
1414 void AliPythia6::SetIntrinsicKt(Float_t kt)
1416 // Set the inreinsic kt
1420 SetPARP(93, 4. * kt);
1426 void AliPythia6::SwitchHFOff()
1428 // Switch off heavy flavor
1429 // Maximum number of quark flavours used in pdf
1431 // Maximum number of flavors that can be used in showers
1435 void AliPythia6::SetPycellParameters(Float_t etamax, Int_t neta, Int_t nphi,
1436 Float_t thresh, Float_t etseed, Float_t minet, Float_t r)
1438 // Set pycell parameters
1439 SetPARU(51, etamax);
1442 SetPARU(58, thresh);
1443 SetPARU(52, etseed);
1449 void AliPythia6::ModifiedSplitting()
1451 // Modified splitting probability as a model for quenching
1453 SetMSTJ(41, 1); // QCD radiation only
1454 SetMSTJ(42, 2); // angular ordering
1455 SetMSTJ(44, 2); // option to run alpha_s
1456 SetMSTJ(47, 0); // No correction back to hard scattering element
1457 SetMSTJ(50, 0); // No coherence in first branching
1458 SetPARJ(82, 1.); // Cut off for parton showers
1461 void AliPythia6::SwitchHadronisationOff()
1463 // Switch off hadronisarion
1467 void AliPythia6::SwitchHadronisationOn()
1469 // Switch on hadronisarion
1474 void AliPythia6::GetXandQ(Float_t& x1, Float_t& x2, Float_t& q)
1476 // Get x1, x2 and Q for this event
1483 Float_t AliPythia6::GetXSection()
1485 // Get the total cross-section
1486 return (GetPARI(1));
1489 Float_t AliPythia6::GetPtHard()
1491 // Get the pT hard for this event
1495 Int_t AliPythia6::ProcessCode()
1497 // Get the subprocess code
1501 void AliPythia6::PrintStatistics()
1503 // End of run statistics
1507 void AliPythia6::EventListing()
1509 // End of run statistics
1513 AliPythia6& AliPythia6::operator=(const AliPythia6& rhs)
1515 // Assignment operator
1520 void AliPythia6::Copy(TObject&) const
1525 Fatal("Copy","Not implemented!\n");