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
252 case kPyMbAtlasTuneMC09:
253 // Minimum Bias pp-Collisions
256 // select Pythia min. bias model
258 SetMSUB(92,1); // single diffraction AB-->XB
259 SetMSUB(93,1); // single diffraction AB-->AX
260 SetMSUB(94,1); // double diffraction
261 SetMSUB(95,1); // low pt production
266 case kPyMbWithDirectPhoton:
267 // Minimum Bias pp-Collisions with direct photon processes added
270 // select Pythia min. bias model
272 SetMSUB(92,1); // single diffraction AB-->XB
273 SetMSUB(93,1); // single diffraction AB-->AX
274 SetMSUB(94,1); // double diffraction
275 SetMSUB(95,1); // low pt production
288 // Minimum Bias pp-Collisions
291 // select Pythia min. bias model
293 SetMSUB(92,1); // single diffraction AB-->XB
294 SetMSUB(93,1); // single diffraction AB-->AX
295 SetMSUB(94,1); // double diffraction
296 SetMSUB(95,1); // low pt production
300 // Les Houches Working Group 05 Minimum Bias pp-Collisions: hep-ph/0604120
301 // -> Pythia 6.3 or above is needed
304 SetMSUB(92,1); // single diffraction AB-->XB
305 SetMSUB(93,1); // single diffraction AB-->AX
306 SetMSUB(94,1); // double diffraction
307 SetMSUB(95,1); // low pt production
308 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ6ll));
312 SetMSTP(81,1); // Multiple Interactions ON
313 SetMSTP(82,4); // Double Gaussian Model
316 SetPARP(82,2.3); // [GeV] PT_min at Ref. energy
317 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
318 SetPARP(84,0.5); // Core radius
319 SetPARP(85,0.9); // Regulates gluon prod. mechanism
320 SetPARP(90,0.2); // 2*epsilon (exponent in power law)
324 // Minimum Bias pp-Collisions
327 // select Pythia min. bias model
329 SetMSUB(95,1); // low pt production
336 SetMSTP(91,1);// Width (1=gaussian) primordial kT dist. inside hadrons
337 SetPARP(91,1.); // <kT^2> = PARP(91,1.)^2
338 SetPARP(93,5.); // Upper cut-off
340 SetPMAS(4,1,1.2); // Charm quark mass
341 SetPMAS(5,1,4.78); // Beauty quark mass
342 SetPARP(71,4.); // Defaut value
351 // Pythia Tune A (CDF)
353 SetPARP(67,2.5); // Regulates Initial State Radiation (value from best fit to D0 dijet analysis)
354 SetMSTP(82,4); // Double Gaussian Model
355 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
356 SetPARP(84,0.4); // Core radius
357 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
358 SetPARP(86,0.95); // Regulates gluon prod. mechanism
359 SetPARP(89,1800.); // [GeV] Ref. energy
360 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
365 case kPyCharmPbPbMNR:
367 case kPyDPlusPbPbMNR:
368 case kPyDPlusStrangePbPbMNR:
369 // Tuning of Pythia parameters aimed to get a resonable agreement
370 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
371 // c-cbar single inclusive and double differential distributions.
372 // This parameter settings are meant to work with Pb-Pb collisions
373 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
374 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
375 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
387 case kPyDPlusStrangepPbMNR:
388 // Tuning of Pythia parameters aimed to get a resonable agreement
389 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
390 // c-cbar single inclusive and double differential distributions.
391 // This parameter settings are meant to work with p-Pb collisions
392 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
393 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
394 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
407 case kPyDPlusStrangeppMNR:
408 case kPyLambdacppMNR:
409 // Tuning of Pythia parameters aimed to get a resonable agreement
410 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
411 // c-cbar single inclusive and double differential distributions.
412 // This parameter settings are meant to work with pp collisions
413 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
414 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
415 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
425 case kPyCharmppMNRwmi:
426 // Tuning of Pythia parameters aimed to get a resonable agreement
427 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
428 // c-cbar single inclusive and double differential distributions.
429 // This parameter settings are meant to work with pp collisions
430 // and with kCTEQ5L PDFs.
431 // Added multiple interactions according to ATLAS tune settings.
432 // To get a "reasonable" agreement with MNR results, events have to be
433 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
435 // To get a "perfect" agreement with MNR results, events have to be
436 // generated in four ptHard bins with the following relative
452 case kPyBeautyPbPbMNR:
453 // Tuning of Pythia parameters aimed to get a resonable agreement
454 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
455 // b-bbar single inclusive and double differential distributions.
456 // This parameter settings are meant to work with Pb-Pb collisions
457 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
458 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
459 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
471 case kPyBeautypPbMNR:
472 // Tuning of Pythia parameters aimed to get a resonable agreement
473 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
474 // b-bbar single inclusive and double differential distributions.
475 // This parameter settings are meant to work with p-Pb collisions
476 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
477 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
478 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
491 // Tuning of Pythia parameters aimed to get a resonable agreement
492 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
493 // b-bbar single inclusive and double differential distributions.
494 // This parameter settings are meant to work with pp collisions
495 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
496 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
497 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
512 case kPyBeautyppMNRwmi:
513 // Tuning of Pythia parameters aimed to get a resonable agreement
514 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
515 // b-bbar single inclusive and double differential distributions.
516 // This parameter settings are meant to work with pp collisions
517 // and with kCTEQ5L PDFs.
518 // Added multiple interactions according to ATLAS tune settings.
519 // To get a "reasonable" agreement with MNR results, events have to be
520 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
522 // To get a "perfect" agreement with MNR results, events have to be
523 // generated in four ptHard bins with the following relative
546 //Inclusive production of W+/-
552 // //f fbar -> gamma W+
559 // Initial/final parton shower on (Pythia default)
560 // With parton showers on we are generating "W inclusive process"
561 SetMSTP(61,1); //Initial QCD & QED showers on
562 SetMSTP(71,1); //Final QCD & QED showers on
568 //Inclusive production of Z
573 // // f fbar -> g Z/gamma
575 // // f fbar -> gamma Z/gamma
577 // // f g -> f Z/gamma
579 // // f gamma -> f Z/gamma
582 //only Z included, not gamma
585 // Initial/final parton shower on (Pythia default)
586 // With parton showers on we are generating "Z inclusive process"
587 SetMSTP(61,1); //Initial QCD & QED showers on
588 SetMSTP(71,1); //Final QCD & QED showers on
595 SetMSTP(41,1); // all resonance decays switched on
596 Initialize("CMS","p","p",fEcms);
600 Int_t AliPythia6::CheckedLuComp(Int_t kf)
602 // Check Lund particle code (for debugging)
607 void AliPythia6::SetNuclei(Int_t a1, Int_t a2)
609 // Treat protons as inside nuclei with mass numbers a1 and a2
610 // The MSTP array in the PYPARS common block is used to enable and
611 // select the nuclear structure functions.
612 // MSTP(52) : (D=1) choice of proton and nuclear structure-function library
613 // =1: internal PYTHIA acording to MSTP(51)
614 // =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
615 // If the following mass number both not equal zero, nuclear corrections of the stf are used.
616 // MSTP(192) : Mass number of nucleus side 1
617 // MSTP(193) : Mass number of nucleus side 2
624 AliPythia6* AliPythia6::Instance()
626 // Set random number generator
630 fgAliPythia = new AliPythia6();
635 void AliPythia6::PrintParticles()
637 // Print list of particl properties
639 char* name = new char[16];
640 for (Int_t kf=0; kf<1000000; kf++) {
641 for (Int_t c = 1; c > -2; c-=2) {
642 Int_t kc = Pycomp(c*kf);
644 Float_t mass = GetPMAS(kc,1);
645 Float_t width = GetPMAS(kc,2);
646 Float_t tau = GetPMAS(kc,4);
652 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
653 c*kf, name, mass, width, tau);
657 printf("\n Number of particles %d \n \n", np);
660 void AliPythia6::ResetDecayTable()
662 // Set default values for pythia decay switches
664 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
665 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
668 void AliPythia6::SetDecayTable()
670 // Set default values for pythia decay switches
673 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
674 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
677 void AliPythia6::Pyclus(Int_t& njet)
679 // Call Pythia clustering algorithm
684 void AliPythia6::Pycell(Int_t& njet)
686 // Call Pythia jet reconstruction algorithm
691 void AliPythia6::GetJet(Int_t i, Float_t& px, Float_t& py, Float_t& pz, Float_t& e)
695 px = GetPyjets()->P[0][n+i];
696 py = GetPyjets()->P[1][n+i];
697 pz = GetPyjets()->P[2][n+i];
698 e = GetPyjets()->P[3][n+i];
701 void AliPythia6::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
703 // Call Pythia showering
705 pyshow(ip1, ip2, qmax);
708 void AliPythia6::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
710 pyrobo(imi, ima, the, phi, bex, bey, bez);
715 void AliPythia6::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod, Float_t zmax, Int_t ngmax)
718 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
719 // (2) The nuclear geometry using the Glauber Model
722 fGlauber = AliFastGlauber::Instance();
724 fGlauber->SetCentralityClass(cMin, cMax);
726 fQuenchingWeights = new AliQuenchingWeights();
727 fQuenchingWeights->InitMult();
728 fQuenchingWeights->SetK(k);
729 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
736 void AliPythia6::Quench()
740 // Simple Jet Quenching routine:
741 // =============================
742 // The jet formed by all final state partons radiated by the parton created
743 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
744 // the initial parton reference frame:
745 // (E + p_z)new = (1-z) (E + p_z)old
750 // The lost momentum is first balanced by one gluon with virtuality > 0.
751 // Subsequently the gluon splits to yield two gluons with E = p.
755 static Float_t eMean = 0.;
756 static Int_t icall = 0;
761 Int_t klast[4] = {-1, -1, -1, -1};
763 Int_t numpart = fPyjets->N;
764 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
765 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
773 // Sore information about Primary partons
776 // 0, 1 partons from hard scattering
777 // 2, 3 partons from initial state radiation
779 for (Int_t i = 2; i <= 7; i++) {
781 // Skip gluons that participate in hard scattering
782 if (i == 4 || i == 5) continue;
783 // Gluons from hard Scattering
784 if (i == 6 || i == 7) {
786 pxq[j] = fPyjets->P[0][i];
787 pyq[j] = fPyjets->P[1][i];
788 pzq[j] = fPyjets->P[2][i];
789 eq[j] = fPyjets->P[3][i];
790 mq[j] = fPyjets->P[4][i];
792 // Gluons from initial state radiation
794 // Obtain 4-momentum vector from difference between original parton and parton after gluon
795 // radiation. Energy is calculated independently because initial state radition does not
796 // conserve strictly momentum and energy for each partonic system independently.
798 // Not very clean. Should be improved !
802 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
803 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
804 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
805 mq[j] = fPyjets->P[4][i];
806 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
809 // Calculate some kinematic variables
811 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
812 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
813 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
814 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
815 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
816 qPdg[j] = fPyjets->K[1][i];
822 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
824 for (Int_t j = 0; j < 4; j++) {
826 // Quench only central jets and with E > 10.
830 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
831 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
833 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
836 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
842 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
843 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
845 // Fractional energy loss
846 fZQuench[j] = eloss / eq[j];
848 // Avoid complete loss
850 if (fZQuench[j] > fZmax) fZQuench[j] = fZmax;
852 // Some debug printing
855 // 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",
856 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
858 // fZQuench[j] = 0.8;
859 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
862 quenched[j] = (fZQuench[j] > 0.01);
867 Double_t pNew[1000][4];
874 for (Int_t isys = 0; isys < 4; isys++) {
875 // Skip to next system if not quenched.
876 if (!quenched[isys]) continue;
878 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
879 if (nGluon[isys] > fNGmax) nGluon[isys] = fNGmax;
880 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
881 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
887 Double_t pg[4] = {0., 0., 0., 0.};
890 // Loop on radiation events
892 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
895 for (Int_t k = 0; k < 4; k++)
902 for (Int_t i = 0; i < numpart; i++)
904 imo = fPyjets->K[2][i];
905 kst = fPyjets->K[0][i];
906 pdg = fPyjets->K[1][i];
910 // Quarks and gluons only
911 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
912 // Particles from hard scattering only
914 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
915 Int_t imom = imo % 1000;
916 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
917 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
920 // Skip comment lines
921 if (kst != 1 && kst != 2) continue;
924 px = fPyjets->P[0][i];
925 py = fPyjets->P[1][i];
926 pz = fPyjets->P[2][i];
927 e = fPyjets->P[3][i];
928 m = fPyjets->P[4][i];
929 pt = TMath::Sqrt(px * px + py * py);
930 p = TMath::Sqrt(px * px + py * py + pz * pz);
931 phi = TMath::Pi() + TMath::ATan2(-py, -px);
932 theta = TMath::ATan2(pt, pz);
935 // Save 4-momentum sum for balancing
946 // Fractional energy loss
947 Double_t z = zquench[index];
950 // Don't fully quench radiated gluons
953 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
958 // printf("z: %d %f\n", imo, z);
965 // Transform into frame in which initial parton is along z-axis
967 TVector3 v(px, py, pz);
968 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
969 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
971 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
972 Double_t mt2 = jt * jt + m * m;
975 // Kinematic limit on z
977 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
979 // Change light-cone kinematics rel. to initial parton
981 Double_t eppzOld = e + pl;
982 Double_t empzOld = e - pl;
984 Double_t eppzNew = (1. - z) * eppzOld;
985 Double_t empzNew = empzOld - mt2 * z / eppzOld;
986 Double_t eNew = 0.5 * (eppzNew + empzNew);
987 Double_t plNew = 0.5 * (eppzNew - empzNew);
991 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
992 Double_t mt2New = eppzNew * empzNew;
993 if (mt2New < 1.e-8) mt2New = 0.;
995 if (m * m > mt2New) {
997 // This should not happen
999 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
1002 jtNew = TMath::Sqrt(mt2New - m * m);
1005 // If pT is to small (probably a leading massive particle) we scale only the energy
1006 // This can cause negative masses of the radiated gluon
1007 // Let's hope for the best ...
1009 eNew = TMath::Sqrt(plNew * plNew + mt2);
1013 // Calculate new px, py
1019 pxNew = jtNew / jt * pxs;
1020 pyNew = jtNew / jt * pys;
1023 // Double_t dpx = pxs - pxNew;
1024 // Double_t dpy = pys - pyNew;
1025 // Double_t dpz = pl - plNew;
1026 // Double_t de = e - eNew;
1027 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
1028 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
1029 // printf("New mass (2) %e %e \n", pxNew, pyNew);
1033 TVector3 w(pxNew, pyNew, plNew);
1034 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
1035 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
1037 p1[index][0] += pxNew;
1038 p1[index][1] += pyNew;
1039 p1[index][2] += plNew;
1040 p1[index][3] += eNew;
1042 // Updated 4-momentum vectors
1044 pNew[icount][0] = pxNew;
1045 pNew[icount][1] = pyNew;
1046 pNew[icount][2] = plNew;
1047 pNew[icount][3] = eNew;
1052 // Check if there was phase-space for quenching
1055 if (icount == 0) quenched[isys] = kFALSE;
1056 if (!quenched[isys]) break;
1058 for (Int_t j = 0; j < 4; j++)
1060 p2[isys][j] = p0[isys][j] - p1[isys][j];
1062 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];
1063 if (p2[isys][4] > 0.) {
1064 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
1067 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
1068 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]);
1069 if (p2[isys][4] < -0.01) {
1070 printf("Negative mass squared !\n");
1071 // Here we have to put the gluon back to mass shell
1072 // This will lead to a small energy imbalance
1074 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
1083 printf("zHeavy lowered to %f\n", zHeavy);
1084 if (zHeavy < 0.01) {
1085 printf("No success ! \n");
1087 quenched[isys] = kFALSE;
1091 } // iteration on z (while)
1093 // Update event record
1094 for (Int_t k = 0; k < icount; k++) {
1095 // 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] );
1096 fPyjets->P[0][kNew[k]] = pNew[k][0];
1097 fPyjets->P[1][kNew[k]] = pNew[k][1];
1098 fPyjets->P[2][kNew[k]] = pNew[k][2];
1099 fPyjets->P[3][kNew[k]] = pNew[k][3];
1106 if (!quenched[isys]) continue;
1108 // Last parton from shower i
1109 Int_t in = klast[isys];
1111 // Continue if no parton in shower i selected
1112 if (in == -1) continue;
1114 // If this is the second initial parton and it is behind the first move pointer by previous ish
1115 if (isys == 1 && klast[1] > klast[0]) in += ish;
1120 // How many additional gluons will be generated
1122 if (p2[isys][4] > 0.05) ish = 2;
1124 // Position of gluons
1126 if (iglu == 0) igMin = iGlu;
1129 (fPyjets->N) += ish;
1132 fPyjets->P[0][iGlu] = p2[isys][0];
1133 fPyjets->P[1][iGlu] = p2[isys][1];
1134 fPyjets->P[2][iGlu] = p2[isys][2];
1135 fPyjets->P[3][iGlu] = p2[isys][3];
1136 fPyjets->P[4][iGlu] = p2[isys][4];
1138 fPyjets->K[0][iGlu] = 1;
1139 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1140 fPyjets->K[1][iGlu] = 21;
1141 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1142 fPyjets->K[3][iGlu] = -1;
1143 fPyjets->K[4][iGlu] = -1;
1145 pg[0] += p2[isys][0];
1146 pg[1] += p2[isys][1];
1147 pg[2] += p2[isys][2];
1148 pg[3] += p2[isys][3];
1151 // Split gluon in rest frame.
1153 Double_t bx = p2[isys][0] / p2[isys][3];
1154 Double_t by = p2[isys][1] / p2[isys][3];
1155 Double_t bz = p2[isys][2] / p2[isys][3];
1156 Double_t pst = p2[isys][4] / 2.;
1158 // Isotropic decay ????
1159 Double_t cost = 2. * gRandom->Rndm() - 1.;
1160 Double_t sint = TMath::Sqrt((1.-cost)*(1.+cost));
1161 Double_t phis = 2. * TMath::Pi() * gRandom->Rndm();
1163 Double_t pz1 = pst * cost;
1164 Double_t pz2 = -pst * cost;
1165 Double_t pt1 = pst * sint;
1166 Double_t pt2 = -pst * sint;
1167 Double_t px1 = pt1 * TMath::Cos(phis);
1168 Double_t py1 = pt1 * TMath::Sin(phis);
1169 Double_t px2 = pt2 * TMath::Cos(phis);
1170 Double_t py2 = pt2 * TMath::Sin(phis);
1172 fPyjets->P[0][iGlu] = px1;
1173 fPyjets->P[1][iGlu] = py1;
1174 fPyjets->P[2][iGlu] = pz1;
1175 fPyjets->P[3][iGlu] = pst;
1176 fPyjets->P[4][iGlu] = 0.;
1178 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 fPyjets->P[0][iGlu+1] = px2;
1185 fPyjets->P[1][iGlu+1] = py2;
1186 fPyjets->P[2][iGlu+1] = pz2;
1187 fPyjets->P[3][iGlu+1] = pst;
1188 fPyjets->P[4][iGlu+1] = 0.;
1190 fPyjets->K[0][iGlu+1] = 1;
1191 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1192 fPyjets->K[1][iGlu+1] = 21;
1193 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1194 fPyjets->K[3][iGlu+1] = -1;
1195 fPyjets->K[4][iGlu+1] = -1;
1201 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1204 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1205 Double_t px, py, pz;
1206 px = fPyjets->P[0][ig];
1207 py = fPyjets->P[1][ig];
1208 pz = fPyjets->P[2][ig];
1209 TVector3 v(px, py, pz);
1210 v.RotateZ(-phiq[isys]);
1211 v.RotateY(-thetaq[isys]);
1212 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1213 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1214 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1215 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1216 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1217 pxs += jtKick * TMath::Cos(phiKick);
1218 pys += jtKick * TMath::Sin(phiKick);
1219 TVector3 w(pxs, pys, pzs);
1220 w.RotateY(thetaq[isys]);
1221 w.RotateZ(phiq[isys]);
1222 fPyjets->P[0][ig] = w.X();
1223 fPyjets->P[1][ig] = w.Y();
1224 fPyjets->P[2][ig] = w.Z();
1225 fPyjets->P[2][ig] = w.Mag();
1231 // Check energy conservation
1235 Double_t es = 14000.;
1237 for (Int_t i = 0; i < numpart; i++)
1239 kst = fPyjets->K[0][i];
1240 if (kst != 1 && kst != 2) continue;
1241 pxs += fPyjets->P[0][i];
1242 pys += fPyjets->P[1][i];
1243 pzs += fPyjets->P[2][i];
1244 es -= fPyjets->P[3][i];
1246 if (TMath::Abs(pxs) > 1.e-2 ||
1247 TMath::Abs(pys) > 1.e-2 ||
1248 TMath::Abs(pzs) > 1.e-1) {
1249 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1250 // Fatal("Quench()", "4-Momentum non-conservation");
1253 } // end quenching loop (systems)
1255 for (Int_t i = 0; i < numpart; i++)
1257 imo = fPyjets->K[2][i];
1259 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1266 void AliPythia6::Pyquen(Double_t a, Int_t ibf, Double_t b)
1268 // Igor Lokthine's quenching routine
1269 // http://lokhtin.web.cern.ch/lokhtin/pyquen/pyquen.txt
1274 void AliPythia6::SetPyquenParameters(Double_t t0, Double_t tau0, Int_t nf, Int_t iengl, Int_t iangl)
1276 // Set the parameters for the PYQUEN package.
1277 // See comments in PyquenCommon.h
1283 PYQPAR.iengl = iengl;
1284 PYQPAR.iangl = iangl;
1287 void AliPythia6::LoadEvent(AliStack* stack, Int_t flag, Int_t reHadr)
1290 // Load event into Pythia Common Block
1293 Int_t npart = stack -> GetNprimary();
1297 GetPyjets()->N = npart;
1299 n0 = GetPyjets()->N;
1300 GetPyjets()->N = n0 + npart;
1304 for (Int_t part = 0; part < npart; part++) {
1305 TParticle *mPart = stack->Particle(part);
1307 Int_t kf = mPart->GetPdgCode();
1308 Int_t ks = mPart->GetStatusCode();
1309 Int_t idf = mPart->GetFirstDaughter();
1310 Int_t idl = mPart->GetLastDaughter();
1313 if (ks == 11 || ks == 12) {
1320 Float_t px = mPart->Px();
1321 Float_t py = mPart->Py();
1322 Float_t pz = mPart->Pz();
1323 Float_t e = mPart->Energy();
1324 Float_t m = mPart->GetCalcMass();
1327 (GetPyjets())->P[0][part+n0] = px;
1328 (GetPyjets())->P[1][part+n0] = py;
1329 (GetPyjets())->P[2][part+n0] = pz;
1330 (GetPyjets())->P[3][part+n0] = e;
1331 (GetPyjets())->P[4][part+n0] = m;
1333 (GetPyjets())->K[1][part+n0] = kf;
1334 (GetPyjets())->K[0][part+n0] = ks;
1335 (GetPyjets())->K[3][part+n0] = idf + 1;
1336 (GetPyjets())->K[4][part+n0] = idl + 1;
1337 (GetPyjets())->K[2][part+n0] = mPart->GetFirstMother() + 1;
1342 void AliPythia6::Pyevnw()
1344 // New multiple interaction scenario
1348 void AliPythia6::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1350 // Return event specific quenching parameters
1353 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];
1357 void AliPythia6::ConfigHeavyFlavor()
1360 // Default configuration for Heavy Flavor production
1362 // All QCD processes
1366 // No multiple interactions
1370 // Initial/final parton shower on (Pythia default)
1374 // 2nd order alpha_s
1382 void AliPythia6::AtlasTuning()
1385 // Configuration for the ATLAS tuning
1386 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ5L));
1387 SetMSTP(81,1); // Multiple Interactions ON
1388 SetMSTP(82,4); // Double Gaussian Model
1389 SetPARP(81,1.9); // Min. pt for multiple interactions (default in 6.2-14)
1390 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
1391 SetPARP(89,1000.); // [GeV] Ref. energy
1392 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
1393 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
1394 SetPARP(84,0.5); // Core radius
1395 SetPARP(85,0.33); // Regulates gluon prod. mechanism
1396 SetPARP(86,0.66); // Regulates gluon prod. mechanism
1397 SetPARP(67,1); // Regulates Initial State Radiation
1400 void AliPythia6::AtlasTuning_MC09()
1403 // Configuration for the ATLAS tuning
1404 printf("ATLAS New TUNE MC09\n");
1405 SetMSTP(81,21); // treatment for MI, ISR, FSR and beam remnants: MI on, new model
1406 SetMSTP(82, 4); // Double Gaussian Model
1407 SetMSTP(52, 2); // External PDF
1408 SetMSTP(51, 20650); // MRST LO*
1411 SetMSTP(70, 0); // (was 2: def manual 1, def code 0) virtuality scale for ISR
1412 SetMSTP(72, 1); // (was 0: def 1) maximum scale for FSR
1413 SetMSTP(88, 1); // (was 0: def 1) strategy for qq junction to di-quark or baryon in beam remnant
1414 SetMSTP(90, 0); // (was 1: def 0) strategy of compensate the primordial kT
1416 SetPARP(78, 0.3); // the amount of color reconnection in the final state
1417 SetPARP(80, 0.1); // probability of color partons kicked out from beam remnant
1418 SetPARP(82, 2.3); // [GeV] PT_min at Ref. energy
1419 SetPARP(83, 0.8); // Core density in proton matter distribution (def.value)
1420 SetPARP(84, 0.7); // Core radius
1421 SetPARP(90, 0.25); // 2*epsilon (exponent in power law)
1422 SetPARJ(81, 0.29); // (was 0.14: def 0.29) Labmda value in running alpha_s for parton showers
1425 SetPARJ(41, 0.3); // a and b parameters of the symmm. Lund FF
1427 SetPARJ(46, 0.75); // mod. of the Lund FF for heavy end-point quarks
1428 SetPARP(89,1800.); // [GeV] Ref. energy
1431 void AliPythia6::SetPtHardRange(Float_t ptmin, Float_t ptmax)
1433 // Set the pt hard range
1438 void AliPythia6::SetYHardRange(Float_t ymin, Float_t ymax)
1440 // Set the y hard range
1446 void AliPythia6::SetFragmentation(Int_t flag)
1448 // Switch fragmentation on/off
1452 void AliPythia6::SetInitialAndFinalStateRadiation(Int_t flag1, Int_t flag2)
1454 // initial state radiation
1456 // final state radiation
1460 void AliPythia6::SetIntrinsicKt(Float_t kt)
1462 // Set the inreinsic kt
1466 SetPARP(93, 4. * kt);
1472 void AliPythia6::SwitchHFOff()
1474 // Switch off heavy flavor
1475 // Maximum number of quark flavours used in pdf
1477 // Maximum number of flavors that can be used in showers
1481 void AliPythia6::SetPycellParameters(Float_t etamax, Int_t neta, Int_t nphi,
1482 Float_t thresh, Float_t etseed, Float_t minet, Float_t r)
1484 // Set pycell parameters
1485 SetPARU(51, etamax);
1488 SetPARU(58, thresh);
1489 SetPARU(52, etseed);
1495 void AliPythia6::ModifiedSplitting()
1497 // Modified splitting probability as a model for quenching
1499 SetMSTJ(41, 1); // QCD radiation only
1500 SetMSTJ(42, 2); // angular ordering
1501 SetMSTJ(44, 2); // option to run alpha_s
1502 SetMSTJ(47, 0); // No correction back to hard scattering element
1503 SetMSTJ(50, 0); // No coherence in first branching
1504 SetPARJ(82, 1.); // Cut off for parton showers
1507 void AliPythia6::SwitchHadronisationOff()
1509 // Switch off hadronisarion
1513 void AliPythia6::SwitchHadronisationOn()
1515 // Switch on hadronisarion
1520 void AliPythia6::GetXandQ(Float_t& x1, Float_t& x2, Float_t& q)
1522 // Get x1, x2 and Q for this event
1529 Float_t AliPythia6::GetXSection()
1531 // Get the total cross-section
1532 return (GetPARI(1));
1535 Float_t AliPythia6::GetPtHard()
1537 // Get the pT hard for this event
1541 Int_t AliPythia6::ProcessCode()
1543 // Get the subprocess code
1547 void AliPythia6::PrintStatistics()
1549 // End of run statistics
1553 void AliPythia6::EventListing()
1555 // End of run statistics
1559 AliPythia6& AliPythia6::operator=(const AliPythia6& rhs)
1561 // Assignment operator
1566 void AliPythia6::Copy(TObject&) const
1571 Fatal("Copy","Not implemented!\n");