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 *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
18 #include "AliPythia.h"
19 #include "AliPythiaRndm.h"
20 #include "../FASTSIM/AliFastGlauber.h"
21 #include "../FASTSIM/AliQuenchingWeights.h"
27 # define pyclus pyclus_
28 # define pycell pycell_
29 # define pyshow pyshow_
30 # define pyrobo pyrobo_
31 # define pyquen pyquen_
34 # define pyclus PYCLUS
35 # define pycell PYCELL
36 # define pyrobo PYROBO
37 # define pyquen PYQUEN
38 # define type_of_call _stdcall
41 extern "C" void type_of_call pyclus(Int_t & );
42 extern "C" void type_of_call pycell(Int_t & );
43 extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
44 extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
45 extern "C" void type_of_call pyquen(Double_t &, Int_t &, Double_t &);
47 //_____________________________________________________________________________
49 AliPythia* AliPythia::fgAliPythia=NULL;
51 AliPythia::AliPythia()
53 // Default Constructor
56 if (!AliPythiaRndm::GetPythiaRandom())
57 AliPythiaRndm::SetPythiaRandom(GetRandom());
59 fQuenchingWeights = 0;
62 void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc)
64 // Initialise the process to generate
65 if (!AliPythiaRndm::GetPythiaRandom())
66 AliPythiaRndm::SetPythiaRandom(GetRandom());
70 fStrucFunc = strucfunc;
71 //...Switch off decay of pi0, K0S, Lambda, Sigma+-, Xi0-, Omega-.
72 SetMDCY(Pycomp(111) ,1,0);
73 SetMDCY(Pycomp(310) ,1,0);
74 SetMDCY(Pycomp(3122),1,0);
75 SetMDCY(Pycomp(3112),1,0);
76 SetMDCY(Pycomp(3212),1,0);
77 SetMDCY(Pycomp(3222),1,0);
78 SetMDCY(Pycomp(3312),1,0);
79 SetMDCY(Pycomp(3322),1,0);
80 SetMDCY(Pycomp(3334),1,0);
81 // select structure function
83 SetMSTP(51,strucfunc);
85 // Pythia initialisation for selected processes//
89 for (Int_t i=1; i<= 200; i++) {
92 // select charm production
95 case kPyOldUEQ2ordered: //Old underlying events with Q2 ordered QCD processes
96 // Multiple interactions on.
98 // Double Gaussian matter distribution.
104 // Reference energy for pT0 and energy rescaling pace.
107 // String drawing almost completely minimizes string length.
110 // ISR and FSR activity.
116 case kPyOldUEQ2ordered2:
117 // Old underlying events with Q2 ordered QCD processes
118 // Multiple interactions on.
120 // Double Gaussian matter distribution.
126 // Reference energy for pT0 and energy rescaling pace.
128 SetPARP(90,0.16); // here is the difference with kPyOldUEQ2ordered
129 // String drawing almost completely minimizes string length.
132 // ISR and FSR activity.
139 // Old production mechanism: Old Popcorn
142 // (D=2) Like MSTJ(12)=2 but added prod ofthe 1er rank baryon
144 // (D=1)see can be used to form baryons (BARYON JUNCTION)
146 SetMSTP(51,kCTEQ5L);// CTEQ 5L ! CTEQ5L pdf
147 SetMSTP(81,1); // Multiple Interactions ON
148 SetMSTP(82,4); // Double Gaussian Model
149 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
150 SetPARP(89,1000.); // [GeV] Ref. energy
151 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
152 SetPARP(83,0.5); // Core density in proton matter dist. (def.value)
153 SetPARP(84,0.5); // Core radius
154 SetPARP(85,0.33); // Regulates gluon prod. mechanism
155 SetPARP(86,0.66); // Regulates gluon prod. mechanism
156 SetPARP(67,1); // Regulate gluon prod. mechanism
160 // heavy quark masses
192 case kPyCharmUnforced:
201 case kPyBeautyUnforced:
211 // Minimum Bias pp-Collisions
214 // select Pythia min. bias model
216 SetMSUB(92,1); // single diffraction AB-->XB
217 SetMSUB(93,1); // single diffraction AB-->AX
218 SetMSUB(94,1); // double diffraction
219 SetMSUB(95,1); // low pt production
225 SetMSTP(51, kCTEQ5L); // CTEQ5L pdf
226 SetMSTP(81,1); // Multiple Interactions ON
227 SetMSTP(82,4); // Double Gaussian Model
229 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
230 SetPARP(89,1000.); // [GeV] Ref. energy
231 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
232 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
233 SetPARP(84,0.5); // Core radius
234 SetPARP(85,0.33); // Regulates gluon prod. mechanism
235 SetPARP(86,0.66); // Regulates gluon prod. mechanism
236 SetPARP(67,1); // Regulates Initial State Radiation
239 // Minimum Bias pp-Collisions
242 // select Pythia min. bias model
244 SetMSUB(95,1); // low pt production
250 SetMSTP(51,kCTEQ5L); // CTEQ5L pdf
251 SetMSTP(81,1); // Multiple Interactions ON
252 SetMSTP(82,4); // Double Gaussian Model
254 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
255 SetPARP(89,1000.); // [GeV] Ref. energy
256 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
257 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
258 SetPARP(84,0.5); // Core radius
259 SetPARP(85,0.33); // Regulates gluon prod. mechanism
260 SetPARP(86,0.66); // Regulates gluon prod. mechanism
261 SetPARP(67,1); // Regulates Initial State Radiation
268 // Pythia Tune A (CDF)
270 SetPARP(67,4.); // Regulates Initial State Radiation
271 SetMSTP(82,4); // Double Gaussian Model
272 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
273 SetPARP(84,0.4); // Core radius
274 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
275 SetPARP(86,0.95); // Regulates gluon prod. mechanism
276 SetPARP(89,1800.); // [GeV] Ref. energy
277 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
282 case kPyCharmPbPbMNR:
284 // Tuning of Pythia parameters aimed to get a resonable agreement
285 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
286 // c-cbar single inclusive and double differential distributions.
287 // This parameter settings are meant to work with Pb-Pb collisions
288 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
289 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
290 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
295 // No multiple interactions
300 // Initial/final parton shower on (Pythia default)
320 case kPyDPlusPbPbMNR:
321 // Tuning of Pythia parameters aimed to get a resonable agreement
322 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
323 // c-cbar single inclusive and double differential distributions.
324 // This parameter settings are meant to work with Pb-Pb collisions
325 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
326 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
327 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
332 // No multiple interactions
337 // Initial/final parton shower on (Pythia default)
359 // Tuning of Pythia parameters aimed to get a resonable agreement
360 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
361 // c-cbar single inclusive and double differential distributions.
362 // This parameter settings are meant to work with p-Pb collisions
363 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
364 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
365 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
370 // No multiple interactions
375 // Initial/final parton shower on (Pythia default)
396 // Tuning of Pythia parameters aimed to get a resonable agreement
397 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
398 // c-cbar single inclusive and double differential distributions.
399 // This parameter settings are meant to work with p-Pb collisions
400 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
401 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
402 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
407 // No multiple interactions
412 // Initial/final parton shower on (Pythia default)
434 // Tuning of Pythia parameters aimed to get a resonable agreement
435 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
436 // c-cbar single inclusive and double differential distributions.
437 // This parameter settings are meant to work with pp collisions
438 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
439 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
440 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
445 // No multiple interactions
450 // Initial/final parton shower on (Pythia default)
471 // Tuning of Pythia parameters aimed to get a resonable agreement
472 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
473 // c-cbar single inclusive and double differential distributions.
474 // This parameter settings are meant to work with pp collisions
475 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
476 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
477 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
482 // No multiple interactions
487 // Initial/final parton shower on (Pythia default)
507 case kPyBeautyPbPbMNR:
508 // Tuning of Pythia parameters aimed to get a resonable agreement
509 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
510 // b-bbar single inclusive and double differential distributions.
511 // This parameter settings are meant to work with Pb-Pb collisions
512 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
513 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
514 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
519 // No multiple interactions
524 // Initial/final parton shower on (Pythia default)
546 case kPyBeautypPbMNR:
547 // Tuning of Pythia parameters aimed to get a resonable agreement
548 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
549 // b-bbar single inclusive and double differential distributions.
550 // This parameter settings are meant to work with p-Pb collisions
551 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
552 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
553 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
558 // No multiple interactions
563 // Initial/final parton shower on (Pythia default)
586 // Tuning of Pythia parameters aimed to get a resonable agreement
587 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
588 // b-bbar single inclusive and double differential distributions.
589 // This parameter settings are meant to work with pp collisions
590 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
591 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
592 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
597 // No multiple interactions
602 // Initial/final parton shower on (Pythia default)
627 //Inclusive production of W+/-
633 // //f fbar -> gamma W+
640 // Initial/final parton shower on (Pythia default)
641 // With parton showers on we are generating "W inclusive process"
642 SetMSTP(61,1); //Initial QCD & QED showers on
643 SetMSTP(71,1); //Final QCD & QED showers on
649 SetMSTP(41,1); // all resonance decays switched on
651 Initialize("CMS","p","p",fEcms);
655 Int_t AliPythia::CheckedLuComp(Int_t kf)
657 // Check Lund particle code (for debugging)
659 printf("\n Lucomp kf,kc %d %d",kf,kc);
663 void AliPythia::SetNuclei(Int_t a1, Int_t a2)
665 // Treat protons as inside nuclei with mass numbers a1 and a2
666 // The MSTP array in the PYPARS common block is used to enable and
667 // select the nuclear structure functions.
668 // MSTP(52) : (D=1) choice of proton and nuclear structure-function library
669 // =1: internal PYTHIA acording to MSTP(51)
670 // =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
671 // If the following mass number both not equal zero, nuclear corrections of the stf are used.
672 // MSTP(192) : Mass number of nucleus side 1
673 // MSTP(193) : Mass number of nucleus side 2
680 AliPythia* AliPythia::Instance()
682 // Set random number generator
686 fgAliPythia = new AliPythia();
691 void AliPythia::PrintParticles()
693 // Print list of particl properties
695 char* name = new char[16];
696 for (Int_t kf=0; kf<1000000; kf++) {
697 for (Int_t c = 1; c > -2; c-=2) {
698 Int_t kc = Pycomp(c*kf);
700 Float_t mass = GetPMAS(kc,1);
701 Float_t width = GetPMAS(kc,2);
702 Float_t tau = GetPMAS(kc,4);
708 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
709 c*kf, name, mass, width, tau);
713 printf("\n Number of particles %d \n \n", np);
716 void AliPythia::ResetDecayTable()
718 // Set default values for pythia decay switches
720 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
721 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
724 void AliPythia::SetDecayTable()
726 // Set default values for pythia decay switches
729 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
730 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
733 void AliPythia::Pyclus(Int_t& njet)
735 // Call Pythia clustering algorithm
740 void AliPythia::Pycell(Int_t& njet)
742 // Call Pythia jet reconstruction algorithm
747 void AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
749 // Call Pythia jet reconstruction algorithm
751 pyshow(ip1, ip2, qmax);
754 void AliPythia::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
756 pyrobo(imi, ima, the, phi, bex, bey, bez);
761 void AliPythia::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod)
764 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
765 // (2) The nuclear geometry using the Glauber Model
769 fGlauber = new AliFastGlauber();
771 fGlauber->SetCentralityClass(cMin, cMax);
773 fQuenchingWeights = new AliQuenchingWeights();
774 fQuenchingWeights->InitMult();
775 fQuenchingWeights->SetK(k);
776 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
780 void AliPythia::Quench()
784 // Simple Jet Quenching routine:
785 // =============================
786 // The jet formed by all final state partons radiated by the parton created
787 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
788 // the initial parton reference frame:
789 // (E + p_z)new = (1-z) (E + p_z)old
794 // The lost momentum is first balanced by one gluon with virtuality > 0.
795 // Subsequently the gluon splits to yield two gluons with E = p.
799 static Float_t eMean = 0.;
800 static Int_t icall = 0;
805 Int_t klast[4] = {-1, -1, -1, -1};
807 Int_t numpart = fPyjets->N;
808 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
809 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
817 // Sore information about Primary partons
820 // 0, 1 partons from hard scattering
821 // 2, 3 partons from initial state radiation
823 for (Int_t i = 2; i <= 7; i++) {
825 // Skip gluons that participate in hard scattering
826 if (i == 4 || i == 5) continue;
827 // Gluons from hard Scattering
828 if (i == 6 || i == 7) {
830 pxq[j] = fPyjets->P[0][i];
831 pyq[j] = fPyjets->P[1][i];
832 pzq[j] = fPyjets->P[2][i];
833 eq[j] = fPyjets->P[3][i];
834 mq[j] = fPyjets->P[4][i];
836 // Gluons from initial state radiation
838 // Obtain 4-momentum vector from difference between original parton and parton after gluon
839 // radiation. Energy is calculated independently because initial state radition does not
840 // conserve strictly momentum and energy for each partonic system independently.
842 // Not very clean. Should be improved !
846 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
847 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
848 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
849 mq[j] = fPyjets->P[4][i];
850 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
853 // Calculate some kinematic variables
855 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
856 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
857 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
858 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
859 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
860 qPdg[j] = fPyjets->K[1][i];
866 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
868 for (Int_t j = 0; j < 4; j++) {
870 // Quench only central jets and with E > 10.
874 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
875 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
877 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
880 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
886 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
887 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
889 // Fractional energy loss
890 fZQuench[j] = eloss / eq[j];
892 // Avoid complete loss
894 if (fZQuench[j] == 1.) fZQuench[j] = 0.95;
896 // Some debug printing
899 // 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",
900 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
902 // fZQuench[j] = 0.8;
903 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
906 quenched[j] = (fZQuench[j] > 0.01);
911 Double_t pNew[1000][4];
918 for (Int_t isys = 0; isys < 4; isys++) {
919 // Skip to next system if not quenched.
920 if (!quenched[isys]) continue;
922 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
923 if (nGluon[isys] > 6) nGluon[isys] = 6;
924 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
925 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
931 Double_t pg[4] = {0., 0., 0., 0.};
934 // Loop on radiation events
936 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
939 for (Int_t k = 0; k < 4; k++)
946 for (Int_t i = 0; i < numpart; i++)
948 imo = fPyjets->K[2][i];
949 kst = fPyjets->K[0][i];
950 pdg = fPyjets->K[1][i];
954 // Quarks and gluons only
955 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
956 // Particles from hard scattering only
958 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
959 Int_t imom = imo % 1000;
960 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
961 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
964 // Skip comment lines
965 if (kst != 1 && kst != 2) continue;
968 px = fPyjets->P[0][i];
969 py = fPyjets->P[1][i];
970 pz = fPyjets->P[2][i];
971 e = fPyjets->P[3][i];
972 m = fPyjets->P[4][i];
973 pt = TMath::Sqrt(px * px + py * py);
974 p = TMath::Sqrt(px * px + py * py + pz * pz);
975 phi = TMath::Pi() + TMath::ATan2(-py, -px);
976 theta = TMath::ATan2(pt, pz);
979 // Save 4-momentum sum for balancing
990 // Fractional energy loss
991 Double_t z = zquench[index];
994 // Don't fully quench radiated gluons
997 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
1002 // printf("z: %d %f\n", imo, z);
1009 // Transform into frame in which initial parton is along z-axis
1011 TVector3 v(px, py, pz);
1012 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
1013 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
1015 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
1016 Double_t mt2 = jt * jt + m * m;
1019 // Kinematic limit on z
1021 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
1023 // Change light-cone kinematics rel. to initial parton
1025 Double_t eppzOld = e + pl;
1026 Double_t empzOld = e - pl;
1028 Double_t eppzNew = (1. - z) * eppzOld;
1029 Double_t empzNew = empzOld - mt2 * z / eppzOld;
1030 Double_t eNew = 0.5 * (eppzNew + empzNew);
1031 Double_t plNew = 0.5 * (eppzNew - empzNew);
1035 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
1036 Double_t mt2New = eppzNew * empzNew;
1037 if (mt2New < 1.e-8) mt2New = 0.;
1039 if (m * m > mt2New) {
1041 // This should not happen
1043 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
1046 jtNew = TMath::Sqrt(mt2New - m * m);
1049 // If pT is to small (probably a leading massive particle) we scale only the energy
1050 // This can cause negative masses of the radiated gluon
1051 // Let's hope for the best ...
1053 eNew = TMath::Sqrt(plNew * plNew + mt2);
1057 // Calculate new px, py
1059 Double_t pxNew = jtNew / jt * pxs;
1060 Double_t pyNew = jtNew / jt * pys;
1062 // Double_t dpx = pxs - pxNew;
1063 // Double_t dpy = pys - pyNew;
1064 // Double_t dpz = pl - plNew;
1065 // Double_t de = e - eNew;
1066 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
1067 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
1068 // printf("New mass (2) %e %e \n", pxNew, pyNew);
1072 TVector3 w(pxNew, pyNew, plNew);
1073 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
1074 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
1076 p1[index][0] += pxNew;
1077 p1[index][1] += pyNew;
1078 p1[index][2] += plNew;
1079 p1[index][3] += eNew;
1081 // Updated 4-momentum vectors
1083 pNew[icount][0] = pxNew;
1084 pNew[icount][1] = pyNew;
1085 pNew[icount][2] = plNew;
1086 pNew[icount][3] = eNew;
1091 // Check if there was phase-space for quenching
1094 if (icount == 0) quenched[isys] = kFALSE;
1095 if (!quenched[isys]) break;
1097 for (Int_t j = 0; j < 4; j++)
1099 p2[isys][j] = p0[isys][j] - p1[isys][j];
1101 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];
1102 if (p2[isys][4] > 0.) {
1103 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
1106 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
1107 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]);
1108 if (p2[isys][4] < -0.01) {
1109 printf("Negative mass squared !\n");
1110 // Here we have to put the gluon back to mass shell
1111 // This will lead to a small energy imbalance
1113 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
1122 printf("zHeavy lowered to %f\n", zHeavy);
1123 if (zHeavy < 0.01) {
1124 printf("No success ! \n");
1126 quenched[isys] = kFALSE;
1130 } // iteration on z (while)
1132 // Update event record
1133 for (Int_t k = 0; k < icount; k++) {
1134 // 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] );
1135 fPyjets->P[0][kNew[k]] = pNew[k][0];
1136 fPyjets->P[1][kNew[k]] = pNew[k][1];
1137 fPyjets->P[2][kNew[k]] = pNew[k][2];
1138 fPyjets->P[3][kNew[k]] = pNew[k][3];
1145 if (!quenched[isys]) continue;
1147 // Last parton from shower i
1148 Int_t in = klast[isys];
1150 // Continue if no parton in shower i selected
1151 if (in == -1) continue;
1153 // If this is the second initial parton and it is behind the first move pointer by previous ish
1154 if (isys == 1 && klast[1] > klast[0]) in += ish;
1159 // How many additional gluons will be generated
1161 if (p2[isys][4] > 0.05) ish = 2;
1163 // Position of gluons
1165 if (iglu == 0) igMin = iGlu;
1168 (fPyjets->N) += ish;
1171 fPyjets->P[0][iGlu] = p2[isys][0];
1172 fPyjets->P[1][iGlu] = p2[isys][1];
1173 fPyjets->P[2][iGlu] = p2[isys][2];
1174 fPyjets->P[3][iGlu] = p2[isys][3];
1175 fPyjets->P[4][iGlu] = p2[isys][4];
1177 fPyjets->K[0][iGlu] = 1;
1178 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1179 fPyjets->K[1][iGlu] = 21;
1180 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1181 fPyjets->K[3][iGlu] = -1;
1182 fPyjets->K[4][iGlu] = -1;
1184 pg[0] += p2[isys][0];
1185 pg[1] += p2[isys][1];
1186 pg[2] += p2[isys][2];
1187 pg[3] += p2[isys][3];
1190 // Split gluon in rest frame.
1192 Double_t bx = p2[isys][0] / p2[isys][3];
1193 Double_t by = p2[isys][1] / p2[isys][3];
1194 Double_t bz = p2[isys][2] / p2[isys][3];
1195 Double_t pst = p2[isys][4] / 2.;
1197 // Isotropic decay ????
1198 Double_t cost = 2. * gRandom->Rndm() - 1.;
1199 Double_t sint = TMath::Sqrt(1. - cost * cost);
1200 Double_t phi = 2. * TMath::Pi() * gRandom->Rndm();
1202 Double_t pz1 = pst * cost;
1203 Double_t pz2 = -pst * cost;
1204 Double_t pt1 = pst * sint;
1205 Double_t pt2 = -pst * sint;
1206 Double_t px1 = pt1 * TMath::Cos(phi);
1207 Double_t py1 = pt1 * TMath::Sin(phi);
1208 Double_t px2 = pt2 * TMath::Cos(phi);
1209 Double_t py2 = pt2 * TMath::Sin(phi);
1211 fPyjets->P[0][iGlu] = px1;
1212 fPyjets->P[1][iGlu] = py1;
1213 fPyjets->P[2][iGlu] = pz1;
1214 fPyjets->P[3][iGlu] = pst;
1215 fPyjets->P[4][iGlu] = 0.;
1217 fPyjets->K[0][iGlu] = 1 ;
1218 fPyjets->K[1][iGlu] = 21;
1219 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1220 fPyjets->K[3][iGlu] = -1;
1221 fPyjets->K[4][iGlu] = -1;
1223 fPyjets->P[0][iGlu+1] = px2;
1224 fPyjets->P[1][iGlu+1] = py2;
1225 fPyjets->P[2][iGlu+1] = pz2;
1226 fPyjets->P[3][iGlu+1] = pst;
1227 fPyjets->P[4][iGlu+1] = 0.;
1229 fPyjets->K[0][iGlu+1] = 1;
1230 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1231 fPyjets->K[1][iGlu+1] = 21;
1232 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1233 fPyjets->K[3][iGlu+1] = -1;
1234 fPyjets->K[4][iGlu+1] = -1;
1240 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1243 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1244 Double_t px, py, pz;
1245 px = fPyjets->P[0][ig];
1246 py = fPyjets->P[1][ig];
1247 pz = fPyjets->P[2][ig];
1248 TVector3 v(px, py, pz);
1249 v.RotateZ(-phiq[isys]);
1250 v.RotateY(-thetaq[isys]);
1251 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1252 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1253 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1254 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1255 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1256 pxs += jtKick * TMath::Cos(phiKick);
1257 pys += jtKick * TMath::Sin(phiKick);
1258 TVector3 w(pxs, pys, pzs);
1259 w.RotateY(thetaq[isys]);
1260 w.RotateZ(phiq[isys]);
1261 fPyjets->P[0][ig] = w.X();
1262 fPyjets->P[1][ig] = w.Y();
1263 fPyjets->P[2][ig] = w.Z();
1264 fPyjets->P[2][ig] = w.Mag();
1270 // Check energy conservation
1274 Double_t es = 14000.;
1276 for (Int_t i = 0; i < numpart; i++)
1278 kst = fPyjets->K[0][i];
1279 if (kst != 1 && kst != 2) continue;
1280 pxs += fPyjets->P[0][i];
1281 pys += fPyjets->P[1][i];
1282 pzs += fPyjets->P[2][i];
1283 es -= fPyjets->P[3][i];
1285 if (TMath::Abs(pxs) > 1.e-2 ||
1286 TMath::Abs(pys) > 1.e-2 ||
1287 TMath::Abs(pzs) > 1.e-1) {
1288 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1289 // Fatal("Quench()", "4-Momentum non-conservation");
1292 } // end quenching loop (systems)
1294 for (Int_t i = 0; i < numpart; i++)
1296 imo = fPyjets->K[2][i];
1298 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1305 void AliPythia::Pyquen(Double_t a, Int_t ibf, Double_t b)
1307 // Igor Lokthine's quenching routine
1311 void AliPythia::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1313 // Return event specific quenching parameters
1316 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];