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_
37 # define py2ent py2ent_
40 # define pyclus PYCLUS
41 # define pycell PYCELL
42 # define pyrobo PYROBO
43 # define pyquen PYQUEN
44 # define pyevnw PYEVNW
45 # define pyshowq PYSHOWQ
46 # define pytune PYTUNE
47 # define py2ent PY2ENT
48 # define type_of_call _stdcall
51 extern "C" void type_of_call pyclus(Int_t & );
52 extern "C" void type_of_call pycell(Int_t & );
53 extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
54 extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
55 extern "C" void type_of_call pyquen(Double_t &, Int_t &, Double_t &);
56 extern "C" void type_of_call pyevnw(){;}
57 extern "C" void type_of_call pyshowq(Int_t &, Int_t &, Double_t &);
58 extern "C" void type_of_call pytune(Int_t &);
59 extern "C" void type_of_call py2ent(Int_t &, Int_t&, Int_t&, Double_t&);
61 //_____________________________________________________________________________
63 AliPythia* AliPythia::fgAliPythia=NULL;
65 AliPythia::AliPythia():
76 // Default Constructor
79 if (!AliPythiaRndm::GetPythiaRandom())
80 AliPythiaRndm::SetPythiaRandom(GetRandom());
82 fQuenchingWeights = 0;
85 AliPythia::AliPythia(const AliPythia& pythia):
102 void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc, Int_t itune)
104 // Initialise the process to generate
105 if (!AliPythiaRndm::GetPythiaRandom())
106 AliPythiaRndm::SetPythiaRandom(GetRandom());
110 fStrucFunc = strucfunc;
111 //...Switch off decay of pi0, K0S, Lambda, Sigma+-, Xi0-, Omega-.
112 SetMDCY(Pycomp(111) ,1,0); // pi0
113 SetMDCY(Pycomp(310) ,1,0); // K0S
114 SetMDCY(Pycomp(3122),1,0); // kLambda
115 SetMDCY(Pycomp(3112),1,0); // sigma -
116 SetMDCY(Pycomp(3212),1,0); // sigma 0
117 SetMDCY(Pycomp(3222),1,0); // sigma +
118 SetMDCY(Pycomp(3312),1,0); // xi -
119 SetMDCY(Pycomp(3322),1,0); // xi 0
120 SetMDCY(Pycomp(3334),1,0); // omega-
121 // Select structure function
123 SetMSTP(51, AliStructFuncType::PDFsetIndex(strucfunc));
124 // Particles produced in string fragmentation point directly to either of the two endpoints
125 // of the string (depending in the side they were generated from).
129 // Pythia initialisation for selected processes//
133 for (Int_t i=1; i<= 200; i++) {
136 // select charm production
139 case kPyOldUEQ2ordered: //Old underlying events with Q2 ordered QCD processes
140 // Multiple interactions on.
142 // Double Gaussian matter distribution.
148 // Reference energy for pT0 and energy rescaling pace.
151 // String drawing almost completely minimizes string length.
154 // ISR and FSR activity.
160 case kPyOldUEQ2ordered2:
161 // Old underlying events with Q2 ordered QCD processes
162 // Multiple interactions on.
164 // Double Gaussian matter distribution.
170 // Reference energy for pT0 and energy rescaling pace.
172 SetPARP(90,0.16); // here is the difference with kPyOldUEQ2ordered
173 // String drawing almost completely minimizes string length.
176 // ISR and FSR activity.
183 // Old production mechanism: Old Popcorn
186 // (D=2) Like MSTJ(12)=2 but added prod ofthe 1er rank baryon
188 // (D=1)see can be used to form baryons (BARYON JUNCTION)
194 // heavy quark masses
224 case kPyCharmUnforced:
233 case kPyBeautyUnforced:
243 // Minimum Bias pp-Collisions
246 // select Pythia min. bias model
248 SetMSUB(92,1); // single diffraction AB-->XB
249 SetMSUB(93,1); // single diffraction AB-->AX
250 SetMSUB(94,1); // double diffraction
251 SetMSUB(95,1); // low pt production
256 case kPyMbWithDirectPhoton:
257 // Minimum Bias pp-Collisions with direct photon processes added
260 // select Pythia min. bias model
262 SetMSUB(92,1); // single diffraction AB-->XB
263 SetMSUB(93,1); // single diffraction AB-->AX
264 SetMSUB(94,1); // double diffraction
265 SetMSUB(95,1); // low pt production
278 // Minimum Bias pp-Collisions
281 // select Pythia min. bias model
283 SetMSUB(92,1); // single diffraction AB-->XB
284 SetMSUB(93,1); // single diffraction AB-->AX
285 SetMSUB(94,1); // double diffraction
286 SetMSUB(95,1); // low pt production
290 // Les Houches Working Group 05 Minimum Bias pp-Collisions: hep-ph/0604120
291 // -> Pythia 6.3 or above is needed
294 SetMSUB(92,1); // single diffraction AB-->XB
295 SetMSUB(93,1); // single diffraction AB-->AX
296 SetMSUB(94,1); // double diffraction
297 SetMSUB(95,1); // low pt production
299 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ6ll)); // CTEQ6ll pdf
303 SetMSTP(81,1); // Multiple Interactions ON
304 SetMSTP(82,4); // Double Gaussian Model
307 SetPARP(82,2.3); // [GeV] PT_min at Ref. energy
308 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
309 SetPARP(84,0.5); // Core radius
310 SetPARP(85,0.9); // Regulates gluon prod. mechanism
311 SetPARP(90,0.2); // 2*epsilon (exponent in power law)
315 // Minimum Bias pp-Collisions
318 // select Pythia min. bias model
320 SetMSUB(95,1); // low pt production
327 SetMSTP(91,1);// Width (1=gaussian) primordial kT dist. inside hadrons
328 SetPARP(91,1.); // <kT^2> = PARP(91,1.)^2
329 SetPARP(93,5.); // Upper cut-off
331 SetPMAS(4,1,1.2); // Charm quark mass
332 SetPMAS(5,1,4.78); // Beauty quark mass
333 SetPARP(71,4.); // Defaut value
342 // Pythia Tune A (CDF)
344 SetPARP(67,2.5); // Regulates Initial State Radiation (value from best fit to D0 dijet analysis)
345 SetMSTP(82,4); // Double Gaussian Model
346 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
347 SetPARP(84,0.4); // Core radius
348 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
349 SetPARP(86,0.95); // Regulates gluon prod. mechanism
350 SetPARP(89,1800.); // [GeV] Ref. energy
351 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
356 case kPyCharmPbPbMNR:
358 case kPyDPlusPbPbMNR:
359 case kPyDPlusStrangePbPbMNR:
360 // Tuning of Pythia parameters aimed to get a resonable agreement
361 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
362 // c-cbar single inclusive and double differential distributions.
363 // This parameter settings are meant to work with Pb-Pb collisions
364 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
365 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
366 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
378 case kPyDPlusStrangepPbMNR:
379 // Tuning of Pythia parameters aimed to get a resonable agreement
380 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
381 // c-cbar single inclusive and double differential distributions.
382 // This parameter settings are meant to work with p-Pb collisions
383 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
384 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
385 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
398 case kPyDPlusStrangeppMNR:
399 // Tuning of Pythia parameters aimed to get a resonable agreement
400 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
401 // c-cbar single inclusive and double differential distributions.
402 // This parameter settings are meant to work with pp collisions
403 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
404 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
405 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
415 case kPyCharmppMNRwmi:
416 // Tuning of Pythia parameters aimed to get a resonable agreement
417 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
418 // c-cbar single inclusive and double differential distributions.
419 // This parameter settings are meant to work with pp collisions
420 // and with kCTEQ5L PDFs.
421 // Added multiple interactions according to ATLAS tune settings.
422 // To get a "reasonable" agreement with MNR results, events have to be
423 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
425 // To get a "perfect" agreement with MNR results, events have to be
426 // generated in four ptHard bins with the following relative
442 case kPyBeautyPbPbMNR:
443 // Tuning of Pythia parameters aimed to get a resonable agreement
444 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
445 // b-bbar single inclusive and double differential distributions.
446 // This parameter settings are meant to work with Pb-Pb collisions
447 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
448 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
449 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
461 case kPyBeautypPbMNR:
462 // Tuning of Pythia parameters aimed to get a resonable agreement
463 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
464 // b-bbar single inclusive and double differential distributions.
465 // This parameter settings are meant to work with p-Pb collisions
466 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
467 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
468 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
481 // Tuning of Pythia parameters aimed to get a resonable agreement
482 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
483 // b-bbar single inclusive and double differential distributions.
484 // This parameter settings are meant to work with pp collisions
485 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
486 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
487 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
502 case kPyBeautyppMNRwmi:
503 // Tuning of Pythia parameters aimed to get a resonable agreement
504 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
505 // b-bbar single inclusive and double differential distributions.
506 // This parameter settings are meant to work with pp collisions
507 // and with kCTEQ5L PDFs.
508 // Added multiple interactions according to ATLAS tune settings.
509 // To get a "reasonable" agreement with MNR results, events have to be
510 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
512 // To get a "perfect" agreement with MNR results, events have to be
513 // generated in four ptHard bins with the following relative
536 //Inclusive production of W+/-
542 // //f fbar -> gamma W+
549 // Initial/final parton shower on (Pythia default)
550 // With parton showers on we are generating "W inclusive process"
551 SetMSTP(61,1); //Initial QCD & QED showers on
552 SetMSTP(71,1); //Final QCD & QED showers on
558 //Inclusive production of Z
563 // // f fbar -> g Z/gamma
565 // // f fbar -> gamma Z/gamma
567 // // f g -> f Z/gamma
569 // // f gamma -> f Z/gamma
572 //only Z included, not gamma
575 // Initial/final parton shower on (Pythia default)
576 // With parton showers on we are generating "Z inclusive process"
577 SetMSTP(61,1); //Initial QCD & QED showers on
578 SetMSTP(71,1); //Final QCD & QED showers on
587 if (itune > -1) Pytune(itune);
590 SetMSTP(41,1); // all resonance decays switched on
591 Initialize("CMS","p","p",fEcms);
595 Int_t AliPythia::CheckedLuComp(Int_t kf)
597 // Check Lund particle code (for debugging)
599 printf("\n Lucomp kf,kc %d %d",kf,kc);
603 void AliPythia::SetNuclei(Int_t a1, Int_t a2, Int_t pdf)
605 // Treat protons as inside nuclei with mass numbers a1 and a2
606 // The MSTP array in the PYPARS common block is used to enable and
607 // select the nuclear structure functions.
608 // MSTP(52) : (D=1) choice of proton and nuclear structure-function library
609 // =1: internal PYTHIA acording to MSTP(51)
610 // =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
611 // If the following mass number both not equal zero, nuclear corrections of the stf are used.
612 // MSTP(192) : Mass number of nucleus side 1
613 // MSTP(193) : Mass number of nucleus side 2
614 // MSTP(194) : Nuclear structure function: 0: EKS98 1:EPS08
622 AliPythia* AliPythia::Instance()
624 // Set random number generator
628 fgAliPythia = new AliPythia();
633 void AliPythia::PrintParticles()
635 // Print list of particl properties
637 char* name = new char[16];
638 for (Int_t kf=0; kf<1000000; kf++) {
639 for (Int_t c = 1; c > -2; c-=2) {
640 Int_t kc = Pycomp(c*kf);
642 Float_t mass = GetPMAS(kc,1);
643 Float_t width = GetPMAS(kc,2);
644 Float_t tau = GetPMAS(kc,4);
650 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
651 c*kf, name, mass, width, tau);
655 printf("\n Number of particles %d \n \n", np);
658 void AliPythia::ResetDecayTable()
660 // Set default values for pythia decay switches
662 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
663 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
666 void AliPythia::SetDecayTable()
668 // Set default values for pythia decay switches
671 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
672 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
675 void AliPythia::Pyclus(Int_t& njet)
677 // Call Pythia clustering algorithm
682 void AliPythia::Pycell(Int_t& njet)
684 // Call Pythia jet reconstruction algorithm
689 void AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
691 // Call Pythia jet reconstruction algorithm
693 pyshow(ip1, ip2, qmax);
696 void AliPythia::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
698 pyrobo(imi, ima, the, phi, bex, bey, bez);
701 void AliPythia::Pytune(Int_t itune)
705 C ITUNE NAME (detailed descriptions below)
706 C 0 Default : No settings changed => linked Pythia version's defaults.
707 C ====== Old UE, Q2-ordered showers ==========================================
708 C 100 A : Rick Field's CDF Tune A
709 C 101 AW : Rick Field's CDF Tune AW
710 C 102 BW : Rick Field's CDF Tune BW
711 C 103 DW : Rick Field's CDF Tune DW
712 C 104 DWT : Rick Field's CDF Tune DW with slower UE energy scaling
713 C 105 QW : Rick Field's CDF Tune QW (NB: needs CTEQ6.1M pdfs externally)
714 C 106 ATLAS-DC2: Arthur Moraes' (old) ATLAS tune (ATLAS DC2 / Rome)
715 C 107 ACR : Tune A modified with annealing CR
716 C 108 D6 : Rick Field's CDF Tune D6 (NB: needs CTEQ6L pdfs externally)
717 C 109 D6T : Rick Field's CDF Tune D6T (NB: needs CTEQ6L pdfs externally)
718 C ====== Intermediate Models =================================================
719 C 200 IM 1 : Intermediate model: new UE, Q2-ordered showers, annealing CR
720 C 201 APT : Tune A modified to use pT-ordered final-state showers
721 C ====== New UE, interleaved pT-ordered showers, annealing CR ================
722 C 300 S0 : Sandhoff-Skands Tune 0
723 C 301 S1 : Sandhoff-Skands Tune 1
724 C 302 S2 : Sandhoff-Skands Tune 2
725 C 303 S0A : S0 with "Tune A" UE energy scaling
726 C 304 NOCR : New UE "best try" without colour reconnections
727 C 305 Old : New UE, original (primitive) colour reconnections
728 C 306 ATLAS-CSC: Arthur Moraes' (new) ATLAS tune (needs CTEQ6L externally)
729 C ======= The Uppsala models =================================================
730 C ( NB! must be run with special modified Pythia 6.215 version )
731 C ( available from http://www.isv.uu.se/thep/MC/scigal/ )
732 C 400 GAL 0 : Generalized area-law model. Old parameters
733 C 401 SCI 0 : Soft-Colour-Interaction model. Old parameters
734 C 402 GAL 1 : Generalized area-law model. Tevatron MB retuned (Skands)
739 void AliPythia::Py2ent(Int_t idx, Int_t pdg1, Int_t pdg2, Double_t p){
740 // Inset 2-parton system at line idx
741 py2ent(idx, pdg1, pdg2, p);
745 void AliPythia::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod, Float_t zmax, Int_t ngmax)
748 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
749 // (2) The nuclear geometry using the Glauber Model
752 fGlauber = AliFastGlauber::Instance();
754 fGlauber->SetCentralityClass(cMin, cMax);
756 fQuenchingWeights = new AliQuenchingWeights();
757 fQuenchingWeights->InitMult();
758 fQuenchingWeights->SetK(k);
759 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
766 void AliPythia::Quench()
770 // Simple Jet Quenching routine:
771 // =============================
772 // The jet formed by all final state partons radiated by the parton created
773 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
774 // the initial parton reference frame:
775 // (E + p_z)new = (1-z) (E + p_z)old
780 // The lost momentum is first balanced by one gluon with virtuality > 0.
781 // Subsequently the gluon splits to yield two gluons with E = p.
785 static Float_t eMean = 0.;
786 static Int_t icall = 0;
791 Int_t klast[4] = {-1, -1, -1, -1};
793 Int_t numpart = fPyjets->N;
794 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
795 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
803 // Sore information about Primary partons
806 // 0, 1 partons from hard scattering
807 // 2, 3 partons from initial state radiation
809 for (Int_t i = 2; i <= 7; i++) {
811 // Skip gluons that participate in hard scattering
812 if (i == 4 || i == 5) continue;
813 // Gluons from hard Scattering
814 if (i == 6 || i == 7) {
816 pxq[j] = fPyjets->P[0][i];
817 pyq[j] = fPyjets->P[1][i];
818 pzq[j] = fPyjets->P[2][i];
819 eq[j] = fPyjets->P[3][i];
820 mq[j] = fPyjets->P[4][i];
822 // Gluons from initial state radiation
824 // Obtain 4-momentum vector from difference between original parton and parton after gluon
825 // radiation. Energy is calculated independently because initial state radition does not
826 // conserve strictly momentum and energy for each partonic system independently.
828 // Not very clean. Should be improved !
832 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
833 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
834 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
835 mq[j] = fPyjets->P[4][i];
836 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
839 // Calculate some kinematic variables
841 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
842 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
843 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
844 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
845 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
846 qPdg[j] = fPyjets->K[1][i];
852 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
854 for (Int_t j = 0; j < 4; j++) {
856 // Quench only central jets and with E > 10.
860 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
861 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
863 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
866 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
872 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
873 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
875 // Fractional energy loss
876 fZQuench[j] = eloss / eq[j];
878 // Avoid complete loss
880 if (fZQuench[j] > fZmax) fZQuench[j] = fZmax;
882 // Some debug printing
885 // 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",
886 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
888 // fZQuench[j] = 0.8;
889 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
892 quenched[j] = (fZQuench[j] > 0.01);
897 Double_t pNew[1000][4];
904 for (Int_t isys = 0; isys < 4; isys++) {
905 // Skip to next system if not quenched.
906 if (!quenched[isys]) continue;
908 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
909 if (nGluon[isys] > fNGmax) nGluon[isys] = fNGmax;
910 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
911 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
917 Double_t pg[4] = {0., 0., 0., 0.};
920 // Loop on radiation events
922 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
925 for (Int_t k = 0; k < 4; k++)
932 for (Int_t i = 0; i < numpart; i++)
934 imo = fPyjets->K[2][i];
935 kst = fPyjets->K[0][i];
936 pdg = fPyjets->K[1][i];
940 // Quarks and gluons only
941 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
942 // Particles from hard scattering only
944 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
945 Int_t imom = imo % 1000;
946 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
947 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
950 // Skip comment lines
951 if (kst != 1 && kst != 2) continue;
954 px = fPyjets->P[0][i];
955 py = fPyjets->P[1][i];
956 pz = fPyjets->P[2][i];
957 e = fPyjets->P[3][i];
958 m = fPyjets->P[4][i];
959 pt = TMath::Sqrt(px * px + py * py);
960 p = TMath::Sqrt(px * px + py * py + pz * pz);
961 phi = TMath::Pi() + TMath::ATan2(-py, -px);
962 theta = TMath::ATan2(pt, pz);
965 // Save 4-momentum sum for balancing
976 // Fractional energy loss
977 Double_t z = zquench[index];
980 // Don't fully quench radiated gluons
983 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
988 // printf("z: %d %f\n", imo, z);
995 // Transform into frame in which initial parton is along z-axis
997 TVector3 v(px, py, pz);
998 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
999 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
1001 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
1002 Double_t mt2 = jt * jt + m * m;
1005 // Kinematic limit on z
1007 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
1009 // Change light-cone kinematics rel. to initial parton
1011 Double_t eppzOld = e + pl;
1012 Double_t empzOld = e - pl;
1014 Double_t eppzNew = (1. - z) * eppzOld;
1015 Double_t empzNew = empzOld - mt2 * z / eppzOld;
1016 Double_t eNew = 0.5 * (eppzNew + empzNew);
1017 Double_t plNew = 0.5 * (eppzNew - empzNew);
1021 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
1022 Double_t mt2New = eppzNew * empzNew;
1023 if (mt2New < 1.e-8) mt2New = 0.;
1025 if (m * m > mt2New) {
1027 // This should not happen
1029 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
1032 jtNew = TMath::Sqrt(mt2New - m * m);
1035 // If pT is to small (probably a leading massive particle) we scale only the energy
1036 // This can cause negative masses of the radiated gluon
1037 // Let's hope for the best ...
1039 eNew = TMath::Sqrt(plNew * plNew + mt2);
1043 // Calculate new px, py
1049 pxNew = jtNew / jt * pxs;
1050 pyNew = jtNew / jt * pys;
1052 // Double_t dpx = pxs - pxNew;
1053 // Double_t dpy = pys - pyNew;
1054 // Double_t dpz = pl - plNew;
1055 // Double_t de = e - eNew;
1056 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
1057 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
1058 // printf("New mass (2) %e %e \n", pxNew, pyNew);
1062 TVector3 w(pxNew, pyNew, plNew);
1063 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
1064 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
1066 p1[index][0] += pxNew;
1067 p1[index][1] += pyNew;
1068 p1[index][2] += plNew;
1069 p1[index][3] += eNew;
1071 // Updated 4-momentum vectors
1073 pNew[icount][0] = pxNew;
1074 pNew[icount][1] = pyNew;
1075 pNew[icount][2] = plNew;
1076 pNew[icount][3] = eNew;
1081 // Check if there was phase-space for quenching
1084 if (icount == 0) quenched[isys] = kFALSE;
1085 if (!quenched[isys]) break;
1087 for (Int_t j = 0; j < 4; j++)
1089 p2[isys][j] = p0[isys][j] - p1[isys][j];
1091 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];
1092 if (p2[isys][4] > 0.) {
1093 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
1096 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
1097 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]);
1098 if (p2[isys][4] < -0.01) {
1099 printf("Negative mass squared !\n");
1100 // Here we have to put the gluon back to mass shell
1101 // This will lead to a small energy imbalance
1103 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
1112 printf("zHeavy lowered to %f\n", zHeavy);
1113 if (zHeavy < 0.01) {
1114 printf("No success ! \n");
1116 quenched[isys] = kFALSE;
1120 } // iteration on z (while)
1122 // Update event record
1123 for (Int_t k = 0; k < icount; k++) {
1124 // 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] );
1125 fPyjets->P[0][kNew[k]] = pNew[k][0];
1126 fPyjets->P[1][kNew[k]] = pNew[k][1];
1127 fPyjets->P[2][kNew[k]] = pNew[k][2];
1128 fPyjets->P[3][kNew[k]] = pNew[k][3];
1135 if (!quenched[isys]) continue;
1137 // Last parton from shower i
1138 Int_t in = klast[isys];
1140 // Continue if no parton in shower i selected
1141 if (in == -1) continue;
1143 // If this is the second initial parton and it is behind the first move pointer by previous ish
1144 if (isys == 1 && klast[1] > klast[0]) in += ish;
1149 // How many additional gluons will be generated
1151 if (p2[isys][4] > 0.05) ish = 2;
1153 // Position of gluons
1155 if (iglu == 0) igMin = iGlu;
1158 (fPyjets->N) += ish;
1161 fPyjets->P[0][iGlu] = p2[isys][0];
1162 fPyjets->P[1][iGlu] = p2[isys][1];
1163 fPyjets->P[2][iGlu] = p2[isys][2];
1164 fPyjets->P[3][iGlu] = p2[isys][3];
1165 fPyjets->P[4][iGlu] = p2[isys][4];
1167 fPyjets->K[0][iGlu] = 1;
1168 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1169 fPyjets->K[1][iGlu] = 21;
1170 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1171 fPyjets->K[3][iGlu] = -1;
1172 fPyjets->K[4][iGlu] = -1;
1174 pg[0] += p2[isys][0];
1175 pg[1] += p2[isys][1];
1176 pg[2] += p2[isys][2];
1177 pg[3] += p2[isys][3];
1180 // Split gluon in rest frame.
1182 Double_t bx = p2[isys][0] / p2[isys][3];
1183 Double_t by = p2[isys][1] / p2[isys][3];
1184 Double_t bz = p2[isys][2] / p2[isys][3];
1185 Double_t pst = p2[isys][4] / 2.;
1187 // Isotropic decay ????
1188 Double_t cost = 2. * gRandom->Rndm() - 1.;
1189 Double_t sint = TMath::Sqrt((1.-cost)*(1.+cost));
1190 Double_t phis = 2. * TMath::Pi() * gRandom->Rndm();
1192 Double_t pz1 = pst * cost;
1193 Double_t pz2 = -pst * cost;
1194 Double_t pt1 = pst * sint;
1195 Double_t pt2 = -pst * sint;
1196 Double_t px1 = pt1 * TMath::Cos(phis);
1197 Double_t py1 = pt1 * TMath::Sin(phis);
1198 Double_t px2 = pt2 * TMath::Cos(phis);
1199 Double_t py2 = pt2 * TMath::Sin(phis);
1201 fPyjets->P[0][iGlu] = px1;
1202 fPyjets->P[1][iGlu] = py1;
1203 fPyjets->P[2][iGlu] = pz1;
1204 fPyjets->P[3][iGlu] = pst;
1205 fPyjets->P[4][iGlu] = 0.;
1207 fPyjets->K[0][iGlu] = 1 ;
1208 fPyjets->K[1][iGlu] = 21;
1209 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1210 fPyjets->K[3][iGlu] = -1;
1211 fPyjets->K[4][iGlu] = -1;
1213 fPyjets->P[0][iGlu+1] = px2;
1214 fPyjets->P[1][iGlu+1] = py2;
1215 fPyjets->P[2][iGlu+1] = pz2;
1216 fPyjets->P[3][iGlu+1] = pst;
1217 fPyjets->P[4][iGlu+1] = 0.;
1219 fPyjets->K[0][iGlu+1] = 1;
1220 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1221 fPyjets->K[1][iGlu+1] = 21;
1222 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1223 fPyjets->K[3][iGlu+1] = -1;
1224 fPyjets->K[4][iGlu+1] = -1;
1230 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1233 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1234 Double_t px, py, pz;
1235 px = fPyjets->P[0][ig];
1236 py = fPyjets->P[1][ig];
1237 pz = fPyjets->P[2][ig];
1238 TVector3 v(px, py, pz);
1239 v.RotateZ(-phiq[isys]);
1240 v.RotateY(-thetaq[isys]);
1241 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1242 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1243 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1244 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1245 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1246 pxs += jtKick * TMath::Cos(phiKick);
1247 pys += jtKick * TMath::Sin(phiKick);
1248 TVector3 w(pxs, pys, pzs);
1249 w.RotateY(thetaq[isys]);
1250 w.RotateZ(phiq[isys]);
1251 fPyjets->P[0][ig] = w.X();
1252 fPyjets->P[1][ig] = w.Y();
1253 fPyjets->P[2][ig] = w.Z();
1254 fPyjets->P[2][ig] = w.Mag();
1260 // Check energy conservation
1264 Double_t es = 14000.;
1266 for (Int_t i = 0; i < numpart; i++)
1268 kst = fPyjets->K[0][i];
1269 if (kst != 1 && kst != 2) continue;
1270 pxs += fPyjets->P[0][i];
1271 pys += fPyjets->P[1][i];
1272 pzs += fPyjets->P[2][i];
1273 es -= fPyjets->P[3][i];
1275 if (TMath::Abs(pxs) > 1.e-2 ||
1276 TMath::Abs(pys) > 1.e-2 ||
1277 TMath::Abs(pzs) > 1.e-1) {
1278 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1279 // Fatal("Quench()", "4-Momentum non-conservation");
1282 } // end quenching loop (systems)
1284 for (Int_t i = 0; i < numpart; i++)
1286 imo = fPyjets->K[2][i];
1288 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1295 void AliPythia::Pyquen(Double_t a, Int_t ibf, Double_t b)
1297 // Igor Lokthine's quenching routine
1298 // http://lokhtin.web.cern.ch/lokhtin/pyquen/pyquen.txt
1303 void AliPythia::SetPyquenParameters(Double_t t0, Double_t tau0, Int_t nf, Int_t iengl, Int_t iangl)
1305 // Set the parameters for the PYQUEN package.
1306 // See comments in PyquenCommon.h
1312 PYQPAR.iengl = iengl;
1313 PYQPAR.iangl = iangl;
1317 void AliPythia::Pyevnw()
1319 // New multiple interaction scenario
1323 void AliPythia::Pyshowq(Int_t ip1, Int_t ip2, Double_t qmax)
1325 // Call medium-modified Pythia jet reconstruction algorithm
1327 pyshowq(ip1, ip2, qmax);
1330 void AliPythia::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1332 // Return event specific quenching parameters
1335 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];
1339 void AliPythia::ConfigHeavyFlavor()
1342 // Default configuration for Heavy Flavor production
1344 // All QCD processes
1348 // No multiple interactions
1352 // Initial/final parton shower on (Pythia default)
1356 // 2nd order alpha_s
1364 void AliPythia::AtlasTuning()
1367 // Configuration for the ATLAS tuning
1368 SetMSTP(51, AliStructFuncType::PDFsetIndex(kCTEQ5L)); // CTEQ5L pdf
1369 SetMSTP(81,1); // Multiple Interactions ON
1370 SetMSTP(82,4); // Double Gaussian Model
1371 SetPARP(81,1.9); // Min. pt for multiple interactions (default in 6.2-14)
1372 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
1373 SetPARP(89,1000.); // [GeV] Ref. energy
1374 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
1375 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
1376 SetPARP(84,0.5); // Core radius
1377 SetPARP(85,0.33); // Regulates gluon prod. mechanism
1378 SetPARP(86,0.66); // Regulates gluon prod. mechanism
1379 SetPARP(67,1); // Regulates Initial State Radiation
1382 AliPythia& AliPythia::operator=(const AliPythia& rhs)
1384 // Assignment operator
1389 void AliPythia::Copy(TObject&) const
1394 Fatal("Copy","Not implemented!\n");