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_
36 # define pytune pytune_
39 # define pyclus PYCLUS
40 # define pycell PYCELL
41 # define pyrobo PYROBO
42 # define pyquen PYQUEN
43 # define pyevnw PYEVNW
44 # define pyshowq PYSHOWQ
45 # define PYTUNE PYTUNE
46 # define type_of_call _stdcall
49 extern "C" void type_of_call pyclus(Int_t & );
50 extern "C" void type_of_call pycell(Int_t & );
51 extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
52 extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
53 extern "C" void type_of_call pyquen(Double_t &, Int_t &, Double_t &);
54 extern "C" void type_of_call pyevnw(){;}
55 extern "C" void type_of_call pyshowq(Int_t &, Int_t &, Double_t &);
56 extern "C" void type_of_call pytune(Int_t &);
58 //_____________________________________________________________________________
60 AliPythia* AliPythia::fgAliPythia=NULL;
62 AliPythia::AliPythia():
73 // Default Constructor
76 if (!AliPythiaRndm::GetPythiaRandom())
77 AliPythiaRndm::SetPythiaRandom(GetRandom());
79 fQuenchingWeights = 0;
82 AliPythia::AliPythia(const AliPythia& pythia):
99 void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc, Int_t itune)
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); // pi0
110 SetMDCY(Pycomp(310) ,1,0); // K0S
111 SetMDCY(Pycomp(3122),1,0); // kLambda
112 SetMDCY(Pycomp(3112),1,0); // sigma -
113 SetMDCY(Pycomp(3212),1,0); // sigma 0
114 SetMDCY(Pycomp(3222),1,0); // sigma +
115 SetMDCY(Pycomp(3312),1,0); // xi -
116 SetMDCY(Pycomp(3322),1,0); // xi 0
117 SetMDCY(Pycomp(3334),1,0); // omega-
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
296 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ6ll)); // CTEQ6ll pdf
300 SetMSTP(81,1); // Multiple Interactions ON
301 SetMSTP(82,4); // Double Gaussian Model
304 SetPARP(82,2.3); // [GeV] PT_min at Ref. energy
305 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
306 SetPARP(84,0.5); // Core radius
307 SetPARP(85,0.9); // Regulates gluon prod. mechanism
308 SetPARP(90,0.2); // 2*epsilon (exponent in power law)
312 // Minimum Bias pp-Collisions
315 // select Pythia min. bias model
317 SetMSUB(95,1); // low pt production
324 SetMSTP(91,1);// Width (1=gaussian) primordial kT dist. inside hadrons
325 SetPARP(91,1.); // <kT^2> = PARP(91,1.)^2
326 SetPARP(93,5.); // Upper cut-off
328 SetPMAS(4,1,1.2); // Charm quark mass
329 SetPMAS(5,1,4.78); // Beauty quark mass
330 SetPARP(71,4.); // Defaut value
339 // Pythia Tune A (CDF)
341 SetPARP(67,2.5); // Regulates Initial State Radiation (value from best fit to D0 dijet analysis)
342 SetMSTP(82,4); // Double Gaussian Model
343 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
344 SetPARP(84,0.4); // Core radius
345 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
346 SetPARP(86,0.95); // Regulates gluon prod. mechanism
347 SetPARP(89,1800.); // [GeV] Ref. energy
348 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
353 case kPyCharmPbPbMNR:
355 case kPyDPlusPbPbMNR:
356 case kPyDPlusStrangePbPbMNR:
357 // Tuning of Pythia parameters aimed to get a resonable agreement
358 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
359 // c-cbar single inclusive and double differential distributions.
360 // This parameter settings are meant to work with Pb-Pb collisions
361 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
362 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
363 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
375 case kPyDPlusStrangepPbMNR:
376 // Tuning of Pythia parameters aimed to get a resonable agreement
377 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
378 // c-cbar single inclusive and double differential distributions.
379 // This parameter settings are meant to work with p-Pb collisions
380 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
381 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
382 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
395 case kPyDPlusStrangeppMNR:
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 pp 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.
412 case kPyCharmppMNRwmi:
413 // Tuning of Pythia parameters aimed to get a resonable agreement
414 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
415 // c-cbar single inclusive and double differential distributions.
416 // This parameter settings are meant to work with pp collisions
417 // and with kCTEQ5L PDFs.
418 // Added multiple interactions according to ATLAS tune settings.
419 // To get a "reasonable" agreement with MNR results, events have to be
420 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
422 // To get a "perfect" agreement with MNR results, events have to be
423 // generated in four ptHard bins with the following relative
439 case kPyBeautyPbPbMNR:
440 // Tuning of Pythia parameters aimed to get a resonable agreement
441 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
442 // b-bbar single inclusive and double differential distributions.
443 // This parameter settings are meant to work with Pb-Pb collisions
444 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
445 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
446 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
458 case kPyBeautypPbMNR:
459 // Tuning of Pythia parameters aimed to get a resonable agreement
460 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
461 // b-bbar single inclusive and double differential distributions.
462 // This parameter settings are meant to work with p-Pb collisions
463 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
464 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
465 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
478 // Tuning of Pythia parameters aimed to get a resonable agreement
479 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
480 // b-bbar single inclusive and double differential distributions.
481 // This parameter settings are meant to work with pp collisions
482 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
483 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
484 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
499 case kPyBeautyppMNRwmi:
500 // Tuning of Pythia parameters aimed to get a resonable agreement
501 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
502 // b-bbar single inclusive and double differential distributions.
503 // This parameter settings are meant to work with pp collisions
504 // and with kCTEQ5L PDFs.
505 // Added multiple interactions according to ATLAS tune settings.
506 // To get a "reasonable" agreement with MNR results, events have to be
507 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
509 // To get a "perfect" agreement with MNR results, events have to be
510 // generated in four ptHard bins with the following relative
533 //Inclusive production of W+/-
539 // //f fbar -> gamma W+
546 // Initial/final parton shower on (Pythia default)
547 // With parton showers on we are generating "W inclusive process"
548 SetMSTP(61,1); //Initial QCD & QED showers on
549 SetMSTP(71,1); //Final QCD & QED showers on
555 //Inclusive production of Z
560 // // f fbar -> g Z/gamma
562 // // f fbar -> gamma Z/gamma
564 // // f g -> f Z/gamma
566 // // f gamma -> f Z/gamma
569 //only Z included, not gamma
572 // Initial/final parton shower on (Pythia default)
573 // With parton showers on we are generating "Z inclusive process"
574 SetMSTP(61,1); //Initial QCD & QED showers on
575 SetMSTP(71,1); //Final QCD & QED showers on
584 if (itune > -1) Pytune(itune);
587 SetMSTP(41,1); // all resonance decays switched on
588 Initialize("CMS","p","p",fEcms);
592 Int_t AliPythia::CheckedLuComp(Int_t kf)
594 // Check Lund particle code (for debugging)
596 printf("\n Lucomp kf,kc %d %d",kf,kc);
600 void AliPythia::SetNuclei(Int_t a1, Int_t a2, Int_t pdf)
602 // Treat protons as inside nuclei with mass numbers a1 and a2
603 // The MSTP array in the PYPARS common block is used to enable and
604 // select the nuclear structure functions.
605 // MSTP(52) : (D=1) choice of proton and nuclear structure-function library
606 // =1: internal PYTHIA acording to MSTP(51)
607 // =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
608 // If the following mass number both not equal zero, nuclear corrections of the stf are used.
609 // MSTP(192) : Mass number of nucleus side 1
610 // MSTP(193) : Mass number of nucleus side 2
611 // MSTP(194) : Nuclear structure function: 0: EKS98 1:EPS08
619 AliPythia* AliPythia::Instance()
621 // Set random number generator
625 fgAliPythia = new AliPythia();
630 void AliPythia::PrintParticles()
632 // Print list of particl properties
634 char* name = new char[16];
635 for (Int_t kf=0; kf<1000000; kf++) {
636 for (Int_t c = 1; c > -2; c-=2) {
637 Int_t kc = Pycomp(c*kf);
639 Float_t mass = GetPMAS(kc,1);
640 Float_t width = GetPMAS(kc,2);
641 Float_t tau = GetPMAS(kc,4);
647 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
648 c*kf, name, mass, width, tau);
652 printf("\n Number of particles %d \n \n", np);
655 void AliPythia::ResetDecayTable()
657 // Set default values for pythia decay switches
659 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
660 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
663 void AliPythia::SetDecayTable()
665 // Set default values for pythia decay switches
668 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
669 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
672 void AliPythia::Pyclus(Int_t& njet)
674 // Call Pythia clustering algorithm
679 void AliPythia::Pycell(Int_t& njet)
681 // Call Pythia jet reconstruction algorithm
686 void AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
688 // Call Pythia jet reconstruction algorithm
690 pyshow(ip1, ip2, qmax);
693 void AliPythia::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);
698 void AliPythia::Pytune(Int_t itune)
705 void AliPythia::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod, Float_t zmax, Int_t ngmax)
708 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
709 // (2) The nuclear geometry using the Glauber Model
712 fGlauber = AliFastGlauber::Instance();
714 fGlauber->SetCentralityClass(cMin, cMax);
716 fQuenchingWeights = new AliQuenchingWeights();
717 fQuenchingWeights->InitMult();
718 fQuenchingWeights->SetK(k);
719 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
726 void AliPythia::Quench()
730 // Simple Jet Quenching routine:
731 // =============================
732 // The jet formed by all final state partons radiated by the parton created
733 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
734 // the initial parton reference frame:
735 // (E + p_z)new = (1-z) (E + p_z)old
740 // The lost momentum is first balanced by one gluon with virtuality > 0.
741 // Subsequently the gluon splits to yield two gluons with E = p.
745 static Float_t eMean = 0.;
746 static Int_t icall = 0;
751 Int_t klast[4] = {-1, -1, -1, -1};
753 Int_t numpart = fPyjets->N;
754 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
755 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
763 // Sore information about Primary partons
766 // 0, 1 partons from hard scattering
767 // 2, 3 partons from initial state radiation
769 for (Int_t i = 2; i <= 7; i++) {
771 // Skip gluons that participate in hard scattering
772 if (i == 4 || i == 5) continue;
773 // Gluons from hard Scattering
774 if (i == 6 || i == 7) {
776 pxq[j] = fPyjets->P[0][i];
777 pyq[j] = fPyjets->P[1][i];
778 pzq[j] = fPyjets->P[2][i];
779 eq[j] = fPyjets->P[3][i];
780 mq[j] = fPyjets->P[4][i];
782 // Gluons from initial state radiation
784 // Obtain 4-momentum vector from difference between original parton and parton after gluon
785 // radiation. Energy is calculated independently because initial state radition does not
786 // conserve strictly momentum and energy for each partonic system independently.
788 // Not very clean. Should be improved !
792 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
793 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
794 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
795 mq[j] = fPyjets->P[4][i];
796 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
799 // Calculate some kinematic variables
801 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
802 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
803 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
804 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
805 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
806 qPdg[j] = fPyjets->K[1][i];
812 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
814 for (Int_t j = 0; j < 4; j++) {
816 // Quench only central jets and with E > 10.
820 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
821 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
823 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
826 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
832 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
833 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
835 // Fractional energy loss
836 fZQuench[j] = eloss / eq[j];
838 // Avoid complete loss
840 if (fZQuench[j] > fZmax) fZQuench[j] = fZmax;
842 // Some debug printing
845 // 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",
846 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
848 // fZQuench[j] = 0.8;
849 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
852 quenched[j] = (fZQuench[j] > 0.01);
857 Double_t pNew[1000][4];
864 for (Int_t isys = 0; isys < 4; isys++) {
865 // Skip to next system if not quenched.
866 if (!quenched[isys]) continue;
868 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
869 if (nGluon[isys] > fNGmax) nGluon[isys] = fNGmax;
870 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
871 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
877 Double_t pg[4] = {0., 0., 0., 0.};
880 // Loop on radiation events
882 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
885 for (Int_t k = 0; k < 4; k++)
892 for (Int_t i = 0; i < numpart; i++)
894 imo = fPyjets->K[2][i];
895 kst = fPyjets->K[0][i];
896 pdg = fPyjets->K[1][i];
900 // Quarks and gluons only
901 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
902 // Particles from hard scattering only
904 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
905 Int_t imom = imo % 1000;
906 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
907 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
910 // Skip comment lines
911 if (kst != 1 && kst != 2) continue;
914 px = fPyjets->P[0][i];
915 py = fPyjets->P[1][i];
916 pz = fPyjets->P[2][i];
917 e = fPyjets->P[3][i];
918 m = fPyjets->P[4][i];
919 pt = TMath::Sqrt(px * px + py * py);
920 p = TMath::Sqrt(px * px + py * py + pz * pz);
921 phi = TMath::Pi() + TMath::ATan2(-py, -px);
922 theta = TMath::ATan2(pt, pz);
925 // Save 4-momentum sum for balancing
936 // Fractional energy loss
937 Double_t z = zquench[index];
940 // Don't fully quench radiated gluons
943 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
948 // printf("z: %d %f\n", imo, z);
955 // Transform into frame in which initial parton is along z-axis
957 TVector3 v(px, py, pz);
958 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
959 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
961 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
962 Double_t mt2 = jt * jt + m * m;
965 // Kinematic limit on z
967 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
969 // Change light-cone kinematics rel. to initial parton
971 Double_t eppzOld = e + pl;
972 Double_t empzOld = e - pl;
974 Double_t eppzNew = (1. - z) * eppzOld;
975 Double_t empzNew = empzOld - mt2 * z / eppzOld;
976 Double_t eNew = 0.5 * (eppzNew + empzNew);
977 Double_t plNew = 0.5 * (eppzNew - empzNew);
981 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
982 Double_t mt2New = eppzNew * empzNew;
983 if (mt2New < 1.e-8) mt2New = 0.;
985 if (m * m > mt2New) {
987 // This should not happen
989 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
992 jtNew = TMath::Sqrt(mt2New - m * m);
995 // If pT is to small (probably a leading massive particle) we scale only the energy
996 // This can cause negative masses of the radiated gluon
997 // Let's hope for the best ...
999 eNew = TMath::Sqrt(plNew * plNew + mt2);
1003 // Calculate new px, py
1009 pxNew = jtNew / jt * pxs;
1010 pyNew = jtNew / jt * pys;
1012 // Double_t dpx = pxs - pxNew;
1013 // Double_t dpy = pys - pyNew;
1014 // Double_t dpz = pl - plNew;
1015 // Double_t de = e - eNew;
1016 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
1017 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
1018 // printf("New mass (2) %e %e \n", pxNew, pyNew);
1022 TVector3 w(pxNew, pyNew, plNew);
1023 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
1024 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
1026 p1[index][0] += pxNew;
1027 p1[index][1] += pyNew;
1028 p1[index][2] += plNew;
1029 p1[index][3] += eNew;
1031 // Updated 4-momentum vectors
1033 pNew[icount][0] = pxNew;
1034 pNew[icount][1] = pyNew;
1035 pNew[icount][2] = plNew;
1036 pNew[icount][3] = eNew;
1041 // Check if there was phase-space for quenching
1044 if (icount == 0) quenched[isys] = kFALSE;
1045 if (!quenched[isys]) break;
1047 for (Int_t j = 0; j < 4; j++)
1049 p2[isys][j] = p0[isys][j] - p1[isys][j];
1051 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];
1052 if (p2[isys][4] > 0.) {
1053 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
1056 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
1057 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]);
1058 if (p2[isys][4] < -0.01) {
1059 printf("Negative mass squared !\n");
1060 // Here we have to put the gluon back to mass shell
1061 // This will lead to a small energy imbalance
1063 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
1072 printf("zHeavy lowered to %f\n", zHeavy);
1073 if (zHeavy < 0.01) {
1074 printf("No success ! \n");
1076 quenched[isys] = kFALSE;
1080 } // iteration on z (while)
1082 // Update event record
1083 for (Int_t k = 0; k < icount; k++) {
1084 // 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] );
1085 fPyjets->P[0][kNew[k]] = pNew[k][0];
1086 fPyjets->P[1][kNew[k]] = pNew[k][1];
1087 fPyjets->P[2][kNew[k]] = pNew[k][2];
1088 fPyjets->P[3][kNew[k]] = pNew[k][3];
1095 if (!quenched[isys]) continue;
1097 // Last parton from shower i
1098 Int_t in = klast[isys];
1100 // Continue if no parton in shower i selected
1101 if (in == -1) continue;
1103 // If this is the second initial parton and it is behind the first move pointer by previous ish
1104 if (isys == 1 && klast[1] > klast[0]) in += ish;
1109 // How many additional gluons will be generated
1111 if (p2[isys][4] > 0.05) ish = 2;
1113 // Position of gluons
1115 if (iglu == 0) igMin = iGlu;
1118 (fPyjets->N) += ish;
1121 fPyjets->P[0][iGlu] = p2[isys][0];
1122 fPyjets->P[1][iGlu] = p2[isys][1];
1123 fPyjets->P[2][iGlu] = p2[isys][2];
1124 fPyjets->P[3][iGlu] = p2[isys][3];
1125 fPyjets->P[4][iGlu] = p2[isys][4];
1127 fPyjets->K[0][iGlu] = 1;
1128 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1129 fPyjets->K[1][iGlu] = 21;
1130 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1131 fPyjets->K[3][iGlu] = -1;
1132 fPyjets->K[4][iGlu] = -1;
1134 pg[0] += p2[isys][0];
1135 pg[1] += p2[isys][1];
1136 pg[2] += p2[isys][2];
1137 pg[3] += p2[isys][3];
1140 // Split gluon in rest frame.
1142 Double_t bx = p2[isys][0] / p2[isys][3];
1143 Double_t by = p2[isys][1] / p2[isys][3];
1144 Double_t bz = p2[isys][2] / p2[isys][3];
1145 Double_t pst = p2[isys][4] / 2.;
1147 // Isotropic decay ????
1148 Double_t cost = 2. * gRandom->Rndm() - 1.;
1149 Double_t sint = TMath::Sqrt((1.-cost)*(1.+cost));
1150 Double_t phis = 2. * TMath::Pi() * gRandom->Rndm();
1152 Double_t pz1 = pst * cost;
1153 Double_t pz2 = -pst * cost;
1154 Double_t pt1 = pst * sint;
1155 Double_t pt2 = -pst * sint;
1156 Double_t px1 = pt1 * TMath::Cos(phis);
1157 Double_t py1 = pt1 * TMath::Sin(phis);
1158 Double_t px2 = pt2 * TMath::Cos(phis);
1159 Double_t py2 = pt2 * TMath::Sin(phis);
1161 fPyjets->P[0][iGlu] = px1;
1162 fPyjets->P[1][iGlu] = py1;
1163 fPyjets->P[2][iGlu] = pz1;
1164 fPyjets->P[3][iGlu] = pst;
1165 fPyjets->P[4][iGlu] = 0.;
1167 fPyjets->K[0][iGlu] = 1 ;
1168 fPyjets->K[1][iGlu] = 21;
1169 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1170 fPyjets->K[3][iGlu] = -1;
1171 fPyjets->K[4][iGlu] = -1;
1173 fPyjets->P[0][iGlu+1] = px2;
1174 fPyjets->P[1][iGlu+1] = py2;
1175 fPyjets->P[2][iGlu+1] = pz2;
1176 fPyjets->P[3][iGlu+1] = pst;
1177 fPyjets->P[4][iGlu+1] = 0.;
1179 fPyjets->K[0][iGlu+1] = 1;
1180 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1181 fPyjets->K[1][iGlu+1] = 21;
1182 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1183 fPyjets->K[3][iGlu+1] = -1;
1184 fPyjets->K[4][iGlu+1] = -1;
1190 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1193 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1194 Double_t px, py, pz;
1195 px = fPyjets->P[0][ig];
1196 py = fPyjets->P[1][ig];
1197 pz = fPyjets->P[2][ig];
1198 TVector3 v(px, py, pz);
1199 v.RotateZ(-phiq[isys]);
1200 v.RotateY(-thetaq[isys]);
1201 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1202 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1203 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1204 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1205 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1206 pxs += jtKick * TMath::Cos(phiKick);
1207 pys += jtKick * TMath::Sin(phiKick);
1208 TVector3 w(pxs, pys, pzs);
1209 w.RotateY(thetaq[isys]);
1210 w.RotateZ(phiq[isys]);
1211 fPyjets->P[0][ig] = w.X();
1212 fPyjets->P[1][ig] = w.Y();
1213 fPyjets->P[2][ig] = w.Z();
1214 fPyjets->P[2][ig] = w.Mag();
1220 // Check energy conservation
1224 Double_t es = 14000.;
1226 for (Int_t i = 0; i < numpart; i++)
1228 kst = fPyjets->K[0][i];
1229 if (kst != 1 && kst != 2) continue;
1230 pxs += fPyjets->P[0][i];
1231 pys += fPyjets->P[1][i];
1232 pzs += fPyjets->P[2][i];
1233 es -= fPyjets->P[3][i];
1235 if (TMath::Abs(pxs) > 1.e-2 ||
1236 TMath::Abs(pys) > 1.e-2 ||
1237 TMath::Abs(pzs) > 1.e-1) {
1238 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1239 // Fatal("Quench()", "4-Momentum non-conservation");
1242 } // end quenching loop (systems)
1244 for (Int_t i = 0; i < numpart; i++)
1246 imo = fPyjets->K[2][i];
1248 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1255 void AliPythia::Pyquen(Double_t a, Int_t ibf, Double_t b)
1257 // Igor Lokthine's quenching routine
1258 // http://lokhtin.web.cern.ch/lokhtin/pyquen/pyquen.txt
1263 void AliPythia::SetPyquenParameters(Double_t t0, Double_t tau0, Int_t nf, Int_t iengl, Int_t iangl)
1265 // Set the parameters for the PYQUEN package.
1266 // See comments in PyquenCommon.h
1272 PYQPAR.iengl = iengl;
1273 PYQPAR.iangl = iangl;
1277 void AliPythia::Pyevnw()
1279 // New multiple interaction scenario
1283 void AliPythia::Pyshowq(Int_t ip1, Int_t ip2, Double_t qmax)
1285 // Call medium-modified Pythia jet reconstruction algorithm
1287 pyshowq(ip1, ip2, qmax);
1290 void AliPythia::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1292 // Return event specific quenching parameters
1295 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];
1299 void AliPythia::ConfigHeavyFlavor()
1302 // Default configuration for Heavy Flavor production
1304 // All QCD processes
1308 // No multiple interactions
1312 // Initial/final parton shower on (Pythia default)
1316 // 2nd order alpha_s
1324 void AliPythia::AtlasTuning()
1327 // Configuration for the ATLAS tuning
1328 SetMSTP(51, AliStructFuncType::PDFsetIndex(kCTEQ5L)); // CTEQ5L pdf
1329 SetMSTP(81,1); // Multiple Interactions ON
1330 SetMSTP(82,4); // Double Gaussian Model
1331 SetPARP(81,1.9); // Min. pt for multiple interactions (default in 6.2-14)
1332 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
1333 SetPARP(89,1000.); // [GeV] Ref. energy
1334 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
1335 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
1336 SetPARP(84,0.5); // Core radius
1337 SetPARP(85,0.33); // Regulates gluon prod. mechanism
1338 SetPARP(86,0.66); // Regulates gluon prod. mechanism
1339 SetPARP(67,1); // Regulates Initial State Radiation
1342 AliPythia& AliPythia::operator=(const AliPythia& rhs)
1344 // Assignment operator
1349 void AliPythia::Copy(TObject&) const
1354 Fatal("Copy","Not implemented!\n");