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 **************************************************************************/
19 #include "AliPythia.h"
20 #include "AliPythiaRndm.h"
21 #include "AliFastGlauber.h"
22 #include "AliQuenchingWeights.h"
24 #include "PyquenCommon.h"
29 # define pyclus pyclus_
30 # define pycell pycell_
31 # define pyshow pyshow_
32 # define pyrobo pyrobo_
33 # define pyquen pyquen_
34 # define pyevnw pyevnw_
35 # define pyshowq pyshowq_
38 # define pyclus PYCLUS
39 # define pycell PYCELL
40 # define pyrobo PYROBO
41 # define pyquen PYQUEN
42 # define pyevnw PYEVNW
43 # define pyshowq PYSHOWQ
44 # define type_of_call _stdcall
47 extern "C" void type_of_call pyclus(Int_t & );
48 extern "C" void type_of_call pycell(Int_t & );
49 extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
50 extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
51 extern "C" void type_of_call pyquen(Double_t &, Int_t &, Double_t &);
52 extern "C" void type_of_call pyevnw(){;}
53 extern "C" void type_of_call pyshowq(Int_t &, Int_t &, Double_t &);
55 //_____________________________________________________________________________
57 AliPythia* AliPythia::fgAliPythia=NULL;
59 AliPythia::AliPythia():
70 // Default Constructor
73 if (!AliPythiaRndm::GetPythiaRandom())
74 AliPythiaRndm::SetPythiaRandom(GetRandom());
76 fQuenchingWeights = 0;
79 AliPythia::AliPythia(const AliPythia& pythia):
96 void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc)
98 // Initialise the process to generate
99 if (!AliPythiaRndm::GetPythiaRandom())
100 AliPythiaRndm::SetPythiaRandom(GetRandom());
104 fStrucFunc = strucfunc;
105 //...Switch off decay of pi0, K0S, Lambda, Sigma+-, Xi0-, Omega-.
106 SetMDCY(Pycomp(111) ,1,0); // pi0
107 SetMDCY(Pycomp(310) ,1,0); // K0S
108 SetMDCY(Pycomp(3122),1,0); // kLambda
109 SetMDCY(Pycomp(3112),1,0); // sigma -
110 SetMDCY(Pycomp(3212),1,0); // sigma 0
111 SetMDCY(Pycomp(3222),1,0); // sigma +
112 SetMDCY(Pycomp(3312),1,0); // xi -
113 SetMDCY(Pycomp(3322),1,0); // xi 0
114 SetMDCY(Pycomp(3334),1,0); // omega-
115 // Select structure function
117 SetMSTP(51, AliStructFuncType::PDFsetIndex(strucfunc));
118 // Particles produced in string fragmentation point directly to either of the two endpoints
119 // of the string (depending in the side they were generated from).
123 // Pythia initialisation for selected processes//
127 for (Int_t i=1; i<= 200; i++) {
130 // select charm production
133 case kPyOldUEQ2ordered: //Old underlying events with Q2 ordered QCD processes
134 // Multiple interactions on.
136 // Double Gaussian matter distribution.
142 // Reference energy for pT0 and energy rescaling pace.
145 // String drawing almost completely minimizes string length.
148 // ISR and FSR activity.
154 case kPyOldUEQ2ordered2:
155 // Old underlying events with Q2 ordered QCD processes
156 // Multiple interactions on.
158 // Double Gaussian matter distribution.
164 // Reference energy for pT0 and energy rescaling pace.
166 SetPARP(90,0.16); // here is the difference with kPyOldUEQ2ordered
167 // String drawing almost completely minimizes string length.
170 // ISR and FSR activity.
177 // Old production mechanism: Old Popcorn
180 // (D=2) Like MSTJ(12)=2 but added prod ofthe 1er rank baryon
182 // (D=1)see can be used to form baryons (BARYON JUNCTION)
188 // heavy quark masses
218 case kPyCharmUnforced:
227 case kPyBeautyUnforced:
237 // Minimum Bias pp-Collisions
240 // select Pythia min. bias model
242 SetMSUB(92,1); // single diffraction AB-->XB
243 SetMSUB(93,1); // single diffraction AB-->AX
244 SetMSUB(94,1); // double diffraction
245 SetMSUB(95,1); // low pt production
250 case kPyMbWithDirectPhoton:
251 // Minimum Bias pp-Collisions with direct photon processes added
254 // select Pythia min. bias model
256 SetMSUB(92,1); // single diffraction AB-->XB
257 SetMSUB(93,1); // single diffraction AB-->AX
258 SetMSUB(94,1); // double diffraction
259 SetMSUB(95,1); // low pt production
272 // Minimum Bias pp-Collisions
275 // select Pythia min. bias model
277 SetMSUB(92,1); // single diffraction AB-->XB
278 SetMSUB(93,1); // single diffraction AB-->AX
279 SetMSUB(94,1); // double diffraction
280 SetMSUB(95,1); // low pt production
284 // Les Houches Working Group 05 Minimum Bias pp-Collisions: hep-ph/0604120
285 // -> Pythia 6.3 or above is needed
288 SetMSUB(92,1); // single diffraction AB-->XB
289 SetMSUB(93,1); // single diffraction AB-->AX
290 SetMSUB(94,1); // double diffraction
291 SetMSUB(95,1); // low pt production
293 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ6ll)); // CTEQ6ll pdf
297 SetMSTP(81,1); // Multiple Interactions ON
298 SetMSTP(82,4); // Double Gaussian Model
301 SetPARP(82,2.3); // [GeV] PT_min at Ref. energy
302 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
303 SetPARP(84,0.5); // Core radius
304 SetPARP(85,0.9); // Regulates gluon prod. mechanism
305 SetPARP(90,0.2); // 2*epsilon (exponent in power law)
309 // Minimum Bias pp-Collisions
312 // select Pythia min. bias model
314 SetMSUB(95,1); // low pt production
321 SetMSTP(91,1);// Width (1=gaussian) primordial kT dist. inside hadrons
322 SetPARP(91,1.); // <kT^2> = PARP(91,1.)^2
323 SetPARP(93,5.); // Upper cut-off
325 SetPMAS(4,1,1.2); // Charm quark mass
326 SetPMAS(5,1,4.78); // Beauty quark mass
327 SetPARP(71,4.); // Defaut value
336 // Pythia Tune A (CDF)
338 SetPARP(67,2.5); // Regulates Initial State Radiation (value from best fit to D0 dijet analysis)
339 SetMSTP(82,4); // Double Gaussian Model
340 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
341 SetPARP(84,0.4); // Core radius
342 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
343 SetPARP(86,0.95); // Regulates gluon prod. mechanism
344 SetPARP(89,1800.); // [GeV] Ref. energy
345 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
350 case kPyCharmPbPbMNR:
352 case kPyDPlusPbPbMNR:
353 case kPyDPlusStrangePbPbMNR:
354 // Tuning of Pythia parameters aimed to get a resonable agreement
355 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
356 // c-cbar single inclusive and double differential distributions.
357 // This parameter settings are meant to work with Pb-Pb collisions
358 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
359 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
360 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
372 case kPyDPlusStrangepPbMNR:
373 // Tuning of Pythia parameters aimed to get a resonable agreement
374 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
375 // c-cbar single inclusive and double differential distributions.
376 // This parameter settings are meant to work with p-Pb collisions
377 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
378 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
379 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
392 case kPyDPlusStrangeppMNR:
393 // Tuning of Pythia parameters aimed to get a resonable agreement
394 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
395 // c-cbar single inclusive and double differential distributions.
396 // This parameter settings are meant to work with pp collisions
397 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
398 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
399 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
409 case kPyCharmppMNRwmi:
410 // Tuning of Pythia parameters aimed to get a resonable agreement
411 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
412 // c-cbar single inclusive and double differential distributions.
413 // This parameter settings are meant to work with pp collisions
414 // and with kCTEQ5L PDFs.
415 // Added multiple interactions according to ATLAS tune settings.
416 // To get a "reasonable" agreement with MNR results, events have to be
417 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
419 // To get a "perfect" agreement with MNR results, events have to be
420 // generated in four ptHard bins with the following relative
436 case kPyBeautyPbPbMNR:
437 // Tuning of Pythia parameters aimed to get a resonable agreement
438 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
439 // b-bbar single inclusive and double differential distributions.
440 // This parameter settings are meant to work with Pb-Pb collisions
441 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
442 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
443 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
455 case kPyBeautypPbMNR:
456 // Tuning of Pythia parameters aimed to get a resonable agreement
457 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
458 // b-bbar single inclusive and double differential distributions.
459 // This parameter settings are meant to work with p-Pb collisions
460 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
461 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
462 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
475 // Tuning of Pythia parameters aimed to get a resonable agreement
476 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
477 // b-bbar single inclusive and double differential distributions.
478 // This parameter settings are meant to work with pp collisions
479 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
480 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
481 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
496 case kPyBeautyppMNRwmi:
497 // Tuning of Pythia parameters aimed to get a resonable agreement
498 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
499 // b-bbar single inclusive and double differential distributions.
500 // This parameter settings are meant to work with pp collisions
501 // and with kCTEQ5L PDFs.
502 // Added multiple interactions according to ATLAS tune settings.
503 // To get a "reasonable" agreement with MNR results, events have to be
504 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
506 // To get a "perfect" agreement with MNR results, events have to be
507 // generated in four ptHard bins with the following relative
530 //Inclusive production of W+/-
536 // //f fbar -> gamma W+
543 // Initial/final parton shower on (Pythia default)
544 // With parton showers on we are generating "W inclusive process"
545 SetMSTP(61,1); //Initial QCD & QED showers on
546 SetMSTP(71,1); //Final QCD & QED showers on
552 //Inclusive production of Z
557 // // f fbar -> g Z/gamma
559 // // f fbar -> gamma Z/gamma
561 // // f g -> f Z/gamma
563 // // f gamma -> f Z/gamma
566 //only Z included, not gamma
569 // Initial/final parton shower on (Pythia default)
570 // With parton showers on we are generating "Z inclusive process"
571 SetMSTP(61,1); //Initial QCD & QED showers on
572 SetMSTP(71,1); //Final QCD & QED showers on
579 SetMSTP(41,1); // all resonance decays switched on
580 Initialize("CMS","p","p",fEcms);
584 Int_t AliPythia::CheckedLuComp(Int_t kf)
586 // Check Lund particle code (for debugging)
588 printf("\n Lucomp kf,kc %d %d",kf,kc);
592 void AliPythia::SetNuclei(Int_t a1, Int_t a2, Int_t pdf)
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
603 // MSTP(194) : Nuclear structure function: 0: EKS98 1:EPS08
611 AliPythia* AliPythia::Instance()
613 // Set random number generator
617 fgAliPythia = new AliPythia();
622 void AliPythia::PrintParticles()
624 // Print list of particl properties
626 char* name = new char[16];
627 for (Int_t kf=0; kf<1000000; kf++) {
628 for (Int_t c = 1; c > -2; c-=2) {
629 Int_t kc = Pycomp(c*kf);
631 Float_t mass = GetPMAS(kc,1);
632 Float_t width = GetPMAS(kc,2);
633 Float_t tau = GetPMAS(kc,4);
639 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
640 c*kf, name, mass, width, tau);
644 printf("\n Number of particles %d \n \n", np);
647 void AliPythia::ResetDecayTable()
649 // Set default values for pythia decay switches
651 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
652 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
655 void AliPythia::SetDecayTable()
657 // Set default values for pythia decay switches
660 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
661 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
664 void AliPythia::Pyclus(Int_t& njet)
666 // Call Pythia clustering algorithm
671 void AliPythia::Pycell(Int_t& njet)
673 // Call Pythia jet reconstruction algorithm
678 void AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
680 // Call Pythia jet reconstruction algorithm
682 pyshow(ip1, ip2, qmax);
685 void AliPythia::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
687 pyrobo(imi, ima, the, phi, bex, bey, bez);
692 void AliPythia::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod, Float_t zmax, Int_t ngmax)
695 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
696 // (2) The nuclear geometry using the Glauber Model
699 fGlauber = AliFastGlauber::Instance();
701 fGlauber->SetCentralityClass(cMin, cMax);
703 fQuenchingWeights = new AliQuenchingWeights();
704 fQuenchingWeights->InitMult();
705 fQuenchingWeights->SetK(k);
706 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
713 void AliPythia::Quench()
717 // Simple Jet Quenching routine:
718 // =============================
719 // The jet formed by all final state partons radiated by the parton created
720 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
721 // the initial parton reference frame:
722 // (E + p_z)new = (1-z) (E + p_z)old
727 // The lost momentum is first balanced by one gluon with virtuality > 0.
728 // Subsequently the gluon splits to yield two gluons with E = p.
732 static Float_t eMean = 0.;
733 static Int_t icall = 0;
738 Int_t klast[4] = {-1, -1, -1, -1};
740 Int_t numpart = fPyjets->N;
741 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
742 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
750 // Sore information about Primary partons
753 // 0, 1 partons from hard scattering
754 // 2, 3 partons from initial state radiation
756 for (Int_t i = 2; i <= 7; i++) {
758 // Skip gluons that participate in hard scattering
759 if (i == 4 || i == 5) continue;
760 // Gluons from hard Scattering
761 if (i == 6 || i == 7) {
763 pxq[j] = fPyjets->P[0][i];
764 pyq[j] = fPyjets->P[1][i];
765 pzq[j] = fPyjets->P[2][i];
766 eq[j] = fPyjets->P[3][i];
767 mq[j] = fPyjets->P[4][i];
769 // Gluons from initial state radiation
771 // Obtain 4-momentum vector from difference between original parton and parton after gluon
772 // radiation. Energy is calculated independently because initial state radition does not
773 // conserve strictly momentum and energy for each partonic system independently.
775 // Not very clean. Should be improved !
779 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
780 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
781 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
782 mq[j] = fPyjets->P[4][i];
783 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
786 // Calculate some kinematic variables
788 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
789 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
790 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
791 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
792 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
793 qPdg[j] = fPyjets->K[1][i];
799 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
801 for (Int_t j = 0; j < 4; j++) {
803 // Quench only central jets and with E > 10.
807 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
808 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
810 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
813 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
819 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
820 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
822 // Fractional energy loss
823 fZQuench[j] = eloss / eq[j];
825 // Avoid complete loss
827 if (fZQuench[j] > fZmax) fZQuench[j] = fZmax;
829 // Some debug printing
832 // 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",
833 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
835 // fZQuench[j] = 0.8;
836 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
839 quenched[j] = (fZQuench[j] > 0.01);
844 Double_t pNew[1000][4];
851 for (Int_t isys = 0; isys < 4; isys++) {
852 // Skip to next system if not quenched.
853 if (!quenched[isys]) continue;
855 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
856 if (nGluon[isys] > fNGmax) nGluon[isys] = fNGmax;
857 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
858 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
864 Double_t pg[4] = {0., 0., 0., 0.};
867 // Loop on radiation events
869 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
872 for (Int_t k = 0; k < 4; k++)
879 for (Int_t i = 0; i < numpart; i++)
881 imo = fPyjets->K[2][i];
882 kst = fPyjets->K[0][i];
883 pdg = fPyjets->K[1][i];
887 // Quarks and gluons only
888 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
889 // Particles from hard scattering only
891 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
892 Int_t imom = imo % 1000;
893 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
894 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
897 // Skip comment lines
898 if (kst != 1 && kst != 2) continue;
901 px = fPyjets->P[0][i];
902 py = fPyjets->P[1][i];
903 pz = fPyjets->P[2][i];
904 e = fPyjets->P[3][i];
905 m = fPyjets->P[4][i];
906 pt = TMath::Sqrt(px * px + py * py);
907 p = TMath::Sqrt(px * px + py * py + pz * pz);
908 phi = TMath::Pi() + TMath::ATan2(-py, -px);
909 theta = TMath::ATan2(pt, pz);
912 // Save 4-momentum sum for balancing
923 // Fractional energy loss
924 Double_t z = zquench[index];
927 // Don't fully quench radiated gluons
930 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
935 // printf("z: %d %f\n", imo, z);
942 // Transform into frame in which initial parton is along z-axis
944 TVector3 v(px, py, pz);
945 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
946 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
948 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
949 Double_t mt2 = jt * jt + m * m;
952 // Kinematic limit on z
954 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
956 // Change light-cone kinematics rel. to initial parton
958 Double_t eppzOld = e + pl;
959 Double_t empzOld = e - pl;
961 Double_t eppzNew = (1. - z) * eppzOld;
962 Double_t empzNew = empzOld - mt2 * z / eppzOld;
963 Double_t eNew = 0.5 * (eppzNew + empzNew);
964 Double_t plNew = 0.5 * (eppzNew - empzNew);
968 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
969 Double_t mt2New = eppzNew * empzNew;
970 if (mt2New < 1.e-8) mt2New = 0.;
972 if (m * m > mt2New) {
974 // This should not happen
976 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
979 jtNew = TMath::Sqrt(mt2New - m * m);
982 // If pT is to small (probably a leading massive particle) we scale only the energy
983 // This can cause negative masses of the radiated gluon
984 // Let's hope for the best ...
986 eNew = TMath::Sqrt(plNew * plNew + mt2);
990 // Calculate new px, py
996 pxNew = jtNew / jt * pxs;
997 pyNew = jtNew / jt * pys;
999 // Double_t dpx = pxs - pxNew;
1000 // Double_t dpy = pys - pyNew;
1001 // Double_t dpz = pl - plNew;
1002 // Double_t de = e - eNew;
1003 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
1004 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
1005 // printf("New mass (2) %e %e \n", pxNew, pyNew);
1009 TVector3 w(pxNew, pyNew, plNew);
1010 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
1011 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
1013 p1[index][0] += pxNew;
1014 p1[index][1] += pyNew;
1015 p1[index][2] += plNew;
1016 p1[index][3] += eNew;
1018 // Updated 4-momentum vectors
1020 pNew[icount][0] = pxNew;
1021 pNew[icount][1] = pyNew;
1022 pNew[icount][2] = plNew;
1023 pNew[icount][3] = eNew;
1028 // Check if there was phase-space for quenching
1031 if (icount == 0) quenched[isys] = kFALSE;
1032 if (!quenched[isys]) break;
1034 for (Int_t j = 0; j < 4; j++)
1036 p2[isys][j] = p0[isys][j] - p1[isys][j];
1038 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];
1039 if (p2[isys][4] > 0.) {
1040 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
1043 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
1044 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]);
1045 if (p2[isys][4] < -0.01) {
1046 printf("Negative mass squared !\n");
1047 // Here we have to put the gluon back to mass shell
1048 // This will lead to a small energy imbalance
1050 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
1059 printf("zHeavy lowered to %f\n", zHeavy);
1060 if (zHeavy < 0.01) {
1061 printf("No success ! \n");
1063 quenched[isys] = kFALSE;
1067 } // iteration on z (while)
1069 // Update event record
1070 for (Int_t k = 0; k < icount; k++) {
1071 // 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] );
1072 fPyjets->P[0][kNew[k]] = pNew[k][0];
1073 fPyjets->P[1][kNew[k]] = pNew[k][1];
1074 fPyjets->P[2][kNew[k]] = pNew[k][2];
1075 fPyjets->P[3][kNew[k]] = pNew[k][3];
1082 if (!quenched[isys]) continue;
1084 // Last parton from shower i
1085 Int_t in = klast[isys];
1087 // Continue if no parton in shower i selected
1088 if (in == -1) continue;
1090 // If this is the second initial parton and it is behind the first move pointer by previous ish
1091 if (isys == 1 && klast[1] > klast[0]) in += ish;
1096 // How many additional gluons will be generated
1098 if (p2[isys][4] > 0.05) ish = 2;
1100 // Position of gluons
1102 if (iglu == 0) igMin = iGlu;
1105 (fPyjets->N) += ish;
1108 fPyjets->P[0][iGlu] = p2[isys][0];
1109 fPyjets->P[1][iGlu] = p2[isys][1];
1110 fPyjets->P[2][iGlu] = p2[isys][2];
1111 fPyjets->P[3][iGlu] = p2[isys][3];
1112 fPyjets->P[4][iGlu] = p2[isys][4];
1114 fPyjets->K[0][iGlu] = 1;
1115 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1116 fPyjets->K[1][iGlu] = 21;
1117 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1118 fPyjets->K[3][iGlu] = -1;
1119 fPyjets->K[4][iGlu] = -1;
1121 pg[0] += p2[isys][0];
1122 pg[1] += p2[isys][1];
1123 pg[2] += p2[isys][2];
1124 pg[3] += p2[isys][3];
1127 // Split gluon in rest frame.
1129 Double_t bx = p2[isys][0] / p2[isys][3];
1130 Double_t by = p2[isys][1] / p2[isys][3];
1131 Double_t bz = p2[isys][2] / p2[isys][3];
1132 Double_t pst = p2[isys][4] / 2.;
1134 // Isotropic decay ????
1135 Double_t cost = 2. * gRandom->Rndm() - 1.;
1136 Double_t sint = TMath::Sqrt((1.-cost)*(1.+cost));
1137 Double_t phis = 2. * TMath::Pi() * gRandom->Rndm();
1139 Double_t pz1 = pst * cost;
1140 Double_t pz2 = -pst * cost;
1141 Double_t pt1 = pst * sint;
1142 Double_t pt2 = -pst * sint;
1143 Double_t px1 = pt1 * TMath::Cos(phis);
1144 Double_t py1 = pt1 * TMath::Sin(phis);
1145 Double_t px2 = pt2 * TMath::Cos(phis);
1146 Double_t py2 = pt2 * TMath::Sin(phis);
1148 fPyjets->P[0][iGlu] = px1;
1149 fPyjets->P[1][iGlu] = py1;
1150 fPyjets->P[2][iGlu] = pz1;
1151 fPyjets->P[3][iGlu] = pst;
1152 fPyjets->P[4][iGlu] = 0.;
1154 fPyjets->K[0][iGlu] = 1 ;
1155 fPyjets->K[1][iGlu] = 21;
1156 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1157 fPyjets->K[3][iGlu] = -1;
1158 fPyjets->K[4][iGlu] = -1;
1160 fPyjets->P[0][iGlu+1] = px2;
1161 fPyjets->P[1][iGlu+1] = py2;
1162 fPyjets->P[2][iGlu+1] = pz2;
1163 fPyjets->P[3][iGlu+1] = pst;
1164 fPyjets->P[4][iGlu+1] = 0.;
1166 fPyjets->K[0][iGlu+1] = 1;
1167 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1168 fPyjets->K[1][iGlu+1] = 21;
1169 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1170 fPyjets->K[3][iGlu+1] = -1;
1171 fPyjets->K[4][iGlu+1] = -1;
1177 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1180 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1181 Double_t px, py, pz;
1182 px = fPyjets->P[0][ig];
1183 py = fPyjets->P[1][ig];
1184 pz = fPyjets->P[2][ig];
1185 TVector3 v(px, py, pz);
1186 v.RotateZ(-phiq[isys]);
1187 v.RotateY(-thetaq[isys]);
1188 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1189 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1190 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1191 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1192 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1193 pxs += jtKick * TMath::Cos(phiKick);
1194 pys += jtKick * TMath::Sin(phiKick);
1195 TVector3 w(pxs, pys, pzs);
1196 w.RotateY(thetaq[isys]);
1197 w.RotateZ(phiq[isys]);
1198 fPyjets->P[0][ig] = w.X();
1199 fPyjets->P[1][ig] = w.Y();
1200 fPyjets->P[2][ig] = w.Z();
1201 fPyjets->P[2][ig] = w.Mag();
1207 // Check energy conservation
1211 Double_t es = 14000.;
1213 for (Int_t i = 0; i < numpart; i++)
1215 kst = fPyjets->K[0][i];
1216 if (kst != 1 && kst != 2) continue;
1217 pxs += fPyjets->P[0][i];
1218 pys += fPyjets->P[1][i];
1219 pzs += fPyjets->P[2][i];
1220 es -= fPyjets->P[3][i];
1222 if (TMath::Abs(pxs) > 1.e-2 ||
1223 TMath::Abs(pys) > 1.e-2 ||
1224 TMath::Abs(pzs) > 1.e-1) {
1225 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1226 // Fatal("Quench()", "4-Momentum non-conservation");
1229 } // end quenching loop (systems)
1231 for (Int_t i = 0; i < numpart; i++)
1233 imo = fPyjets->K[2][i];
1235 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1242 void AliPythia::Pyquen(Double_t a, Int_t ibf, Double_t b)
1244 // Igor Lokthine's quenching routine
1245 // http://lokhtin.web.cern.ch/lokhtin/pyquen/pyquen.txt
1250 void AliPythia::SetPyquenParameters(Double_t t0, Double_t tau0, Int_t nf, Int_t iengl, Int_t iangl)
1252 // Set the parameters for the PYQUEN package.
1253 // See comments in PyquenCommon.h
1259 PYQPAR.iengl = iengl;
1260 PYQPAR.iangl = iangl;
1264 void AliPythia::Pyevnw()
1266 // New multiple interaction scenario
1270 void AliPythia::Pyshowq(Int_t ip1, Int_t ip2, Double_t qmax)
1272 // Call medium-modified Pythia jet reconstruction algorithm
1274 pyshowq(ip1, ip2, qmax);
1277 void AliPythia::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1279 // Return event specific quenching parameters
1282 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];
1286 void AliPythia::ConfigHeavyFlavor()
1289 // Default configuration for Heavy Flavor production
1291 // All QCD processes
1295 // No multiple interactions
1299 // Initial/final parton shower on (Pythia default)
1303 // 2nd order alpha_s
1311 void AliPythia::AtlasTuning()
1314 // Configuration for the ATLAS tuning
1315 SetMSTP(51, AliStructFuncType::PDFsetIndex(kCTEQ5L)); // CTEQ5L pdf
1316 SetMSTP(81,1); // Multiple Interactions ON
1317 SetMSTP(82,4); // Double Gaussian Model
1318 SetPARP(81,1.9); // Min. pt for multiple interactions (default in 6.2-14)
1319 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
1320 SetPARP(89,1000.); // [GeV] Ref. energy
1321 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
1322 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
1323 SetPARP(84,0.5); // Core radius
1324 SetPARP(85,0.33); // Regulates gluon prod. mechanism
1325 SetPARP(86,0.66); // Regulates gluon prod. mechanism
1326 SetPARP(67,1); // Regulates Initial State Radiation
1329 AliPythia& AliPythia::operator=(const AliPythia& rhs)
1331 // Assignment operator
1336 void AliPythia::Copy(TObject&) const
1341 Fatal("Copy","Not implemented!\n");