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 "../FASTSIM/AliFastGlauber.h"
22 #include "../FASTSIM/AliQuenchingWeights.h"
28 # define pyclus pyclus_
29 # define pycell pycell_
30 # define pyshow pyshow_
31 # define pyrobo pyrobo_
32 # define pyquen pyquen_
33 # define pyevnw pyevnw_
36 # define pyclus PYCLUS
37 # define pycell PYCELL
38 # define pyrobo PYROBO
39 # define pyquen PYQUEN
40 # define pyevnw PYEVNW
41 # define type_of_call _stdcall
44 extern "C" void type_of_call pyclus(Int_t & );
45 extern "C" void type_of_call pycell(Int_t & );
46 extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
47 extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
48 extern "C" void type_of_call pyquen(Double_t &, Int_t &, Double_t &);
49 extern "C" void type_of_call pyevnw(){;}
51 //_____________________________________________________________________________
53 AliPythia* AliPythia::fgAliPythia=NULL;
55 AliPythia::AliPythia():
64 // Default Constructor
67 if (!AliPythiaRndm::GetPythiaRandom())
68 AliPythiaRndm::SetPythiaRandom(GetRandom());
70 fQuenchingWeights = 0;
73 AliPythia::AliPythia(const AliPythia& pythia):
88 void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc)
90 // Initialise the process to generate
91 if (!AliPythiaRndm::GetPythiaRandom())
92 AliPythiaRndm::SetPythiaRandom(GetRandom());
96 fStrucFunc = strucfunc;
97 //...Switch off decay of pi0, K0S, Lambda, Sigma+-, Xi0-, Omega-.
98 SetMDCY(Pycomp(111) ,1,0);
99 SetMDCY(Pycomp(310) ,1,0);
100 SetMDCY(Pycomp(3122),1,0);
101 SetMDCY(Pycomp(3112),1,0);
102 SetMDCY(Pycomp(3212),1,0);
103 SetMDCY(Pycomp(3222),1,0);
104 SetMDCY(Pycomp(3312),1,0);
105 SetMDCY(Pycomp(3322),1,0);
106 SetMDCY(Pycomp(3334),1,0);
107 // Select structure function
109 SetMSTP(51,strucfunc);
110 // Particles produced in string fragmentation point directly to either of the two endpoints
111 // of the string (depending in the side they were generated from).
115 // Pythia initialisation for selected processes//
119 for (Int_t i=1; i<= 200; i++) {
122 // select charm production
125 case kPyOldUEQ2ordered: //Old underlying events with Q2 ordered QCD processes
126 // Multiple interactions on.
128 // Double Gaussian matter distribution.
134 // Reference energy for pT0 and energy rescaling pace.
137 // String drawing almost completely minimizes string length.
140 // ISR and FSR activity.
146 case kPyOldUEQ2ordered2:
147 // Old underlying events with Q2 ordered QCD processes
148 // Multiple interactions on.
150 // Double Gaussian matter distribution.
156 // Reference energy for pT0 and energy rescaling pace.
158 SetPARP(90,0.16); // here is the difference with kPyOldUEQ2ordered
159 // String drawing almost completely minimizes string length.
162 // ISR and FSR activity.
169 // Old production mechanism: Old Popcorn
172 // (D=2) Like MSTJ(12)=2 but added prod ofthe 1er rank baryon
174 // (D=1)see can be used to form baryons (BARYON JUNCTION)
180 // heavy quark masses
210 case kPyCharmUnforced:
219 case kPyBeautyUnforced:
229 // Minimum Bias pp-Collisions
232 // select Pythia min. bias model
234 SetMSUB(92,1); // single diffraction AB-->XB
235 SetMSUB(93,1); // single diffraction AB-->AX
236 SetMSUB(94,1); // double diffraction
237 SetMSUB(95,1); // low pt production
242 // Les Houches Working Group 05 Minimum Bias pp-Collisions: hep-ph/0604120
243 // -> Pythia 6.3 or above is needed
246 SetMSUB(92,1); // single diffraction AB-->XB
247 SetMSUB(93,1); // single diffraction AB-->AX
248 SetMSUB(94,1); // double diffraction
249 SetMSUB(95,1); // low pt production
251 SetMSTP(51,kCTEQ6ll); // CTEQ6ll pdf
255 SetMSTP(81,1); // Multiple Interactions ON
256 SetMSTP(82,4); // Double Gaussian Model
259 SetPARP(82,2.3); // [GeV] PT_min at Ref. energy
260 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
261 SetPARP(84,0.5); // Core radius
262 SetPARP(85,0.9); // Regulates gluon prod. mechanism
263 SetPARP(90,0.2); // 2*epsilon (exponent in power law)
267 // Minimum Bias pp-Collisions
270 // select Pythia min. bias model
272 SetMSUB(95,1); // low pt production
279 SetMSTP(91,1);// Width (1=gaussian) primordial kT dist. inside hadrons
280 SetPARP(91,1.); // <kT^2> = PARP(91,1.)^2
281 SetPARP(93,5.); // Upper cut-off
283 SetPMAS(4,1,1.2); // Charm quark mass
284 SetPMAS(5,1,4.78); // Beauty quark mass
285 SetPARP(71,4.); // Defaut value
294 // Pythia Tune A (CDF)
296 SetPARP(67,4.); // Regulates Initial State Radiation
297 SetMSTP(82,4); // Double Gaussian Model
298 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
299 SetPARP(84,0.4); // Core radius
300 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
301 SetPARP(86,0.95); // Regulates gluon prod. mechanism
302 SetPARP(89,1800.); // [GeV] Ref. energy
303 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
308 case kPyCharmPbPbMNR:
310 case kPyDPlusPbPbMNR:
311 case kPyDPlusStrangePbPbMNR:
312 // Tuning of Pythia parameters aimed to get a resonable agreement
313 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
314 // c-cbar single inclusive and double differential distributions.
315 // This parameter settings are meant to work with Pb-Pb collisions
316 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
317 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
318 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
330 case kPyDPlusStrangepPbMNR:
331 // Tuning of Pythia parameters aimed to get a resonable agreement
332 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
333 // c-cbar single inclusive and double differential distributions.
334 // This parameter settings are meant to work with p-Pb collisions
335 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
336 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
337 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
350 case kPyDPlusStrangeppMNR:
351 // Tuning of Pythia parameters aimed to get a resonable agreement
352 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
353 // c-cbar single inclusive and double differential distributions.
354 // This parameter settings are meant to work with pp collisions
355 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
356 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
357 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
367 case kPyCharmppMNRwmi:
368 // Tuning of Pythia parameters aimed to get a resonable agreement
369 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
370 // c-cbar single inclusive and double differential distributions.
371 // This parameter settings are meant to work with pp collisions
372 // and with kCTEQ5L PDFs.
373 // Added multiple interactions according to ATLAS tune settings.
374 // To get a "reasonable" agreement with MNR results, events have to be
375 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
377 // To get a "perfect" agreement with MNR results, events have to be
378 // generated in four ptHard bins with the following relative
394 case kPyBeautyPbPbMNR:
395 // Tuning of Pythia parameters aimed to get a resonable agreement
396 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
397 // b-bbar single inclusive and double differential distributions.
398 // This parameter settings are meant to work with Pb-Pb collisions
399 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
400 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
401 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
413 case kPyBeautypPbMNR:
414 // Tuning of Pythia parameters aimed to get a resonable agreement
415 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
416 // b-bbar single inclusive and double differential distributions.
417 // This parameter settings are meant to work with p-Pb collisions
418 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
419 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
420 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
433 // Tuning of Pythia parameters aimed to get a resonable agreement
434 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
435 // b-bbar single inclusive and double differential distributions.
436 // This parameter settings are meant to work with pp collisions
437 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
438 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
439 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
453 case kPyBeautyppMNRwmi:
454 // Tuning of Pythia parameters aimed to get a resonable agreement
455 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
456 // b-bbar single inclusive and double differential distributions.
457 // This parameter settings are meant to work with pp collisions
458 // and with kCTEQ5L PDFs.
459 // Added multiple interactions according to ATLAS tune settings.
460 // To get a "reasonable" agreement with MNR results, events have to be
461 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
463 // To get a "perfect" agreement with MNR results, events have to be
464 // generated in four ptHard bins with the following relative
487 //Inclusive production of W+/-
493 // //f fbar -> gamma W+
500 // Initial/final parton shower on (Pythia default)
501 // With parton showers on we are generating "W inclusive process"
502 SetMSTP(61,1); //Initial QCD & QED showers on
503 SetMSTP(71,1); //Final QCD & QED showers on
509 //Inclusive production of Z
514 // // f fbar -> g Z/gamma
516 // // f fbar -> gamma Z/gamma
518 // // f g -> f Z/gamma
520 // // f gamma -> f Z/gamma
523 //only Z included, not gamma
526 // Initial/final parton shower on (Pythia default)
527 // With parton showers on we are generating "Z inclusive process"
528 SetMSTP(61,1); //Initial QCD & QED showers on
529 SetMSTP(71,1); //Final QCD & QED showers on
536 SetMSTP(41,1); // all resonance decays switched on
538 Initialize("CMS","p","p",fEcms);
542 Int_t AliPythia::CheckedLuComp(Int_t kf)
544 // Check Lund particle code (for debugging)
546 printf("\n Lucomp kf,kc %d %d",kf,kc);
550 void AliPythia::SetNuclei(Int_t a1, Int_t a2)
552 // Treat protons as inside nuclei with mass numbers a1 and a2
553 // The MSTP array in the PYPARS common block is used to enable and
554 // select the nuclear structure functions.
555 // MSTP(52) : (D=1) choice of proton and nuclear structure-function library
556 // =1: internal PYTHIA acording to MSTP(51)
557 // =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
558 // If the following mass number both not equal zero, nuclear corrections of the stf are used.
559 // MSTP(192) : Mass number of nucleus side 1
560 // MSTP(193) : Mass number of nucleus side 2
567 AliPythia* AliPythia::Instance()
569 // Set random number generator
573 fgAliPythia = new AliPythia();
578 void AliPythia::PrintParticles()
580 // Print list of particl properties
582 char* name = new char[16];
583 for (Int_t kf=0; kf<1000000; kf++) {
584 for (Int_t c = 1; c > -2; c-=2) {
585 Int_t kc = Pycomp(c*kf);
587 Float_t mass = GetPMAS(kc,1);
588 Float_t width = GetPMAS(kc,2);
589 Float_t tau = GetPMAS(kc,4);
595 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
596 c*kf, name, mass, width, tau);
600 printf("\n Number of particles %d \n \n", np);
603 void AliPythia::ResetDecayTable()
605 // Set default values for pythia decay switches
607 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
608 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
611 void AliPythia::SetDecayTable()
613 // Set default values for pythia decay switches
616 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
617 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
620 void AliPythia::Pyclus(Int_t& njet)
622 // Call Pythia clustering algorithm
627 void AliPythia::Pycell(Int_t& njet)
629 // Call Pythia jet reconstruction algorithm
634 void AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
636 // Call Pythia jet reconstruction algorithm
638 pyshow(ip1, ip2, qmax);
641 void AliPythia::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
643 pyrobo(imi, ima, the, phi, bex, bey, bez);
648 void AliPythia::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod)
651 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
652 // (2) The nuclear geometry using the Glauber Model
655 fGlauber = new AliFastGlauber();
657 fGlauber->SetCentralityClass(cMin, cMax);
659 fQuenchingWeights = new AliQuenchingWeights();
660 fQuenchingWeights->InitMult();
661 fQuenchingWeights->SetK(k);
662 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
666 void AliPythia::Quench()
670 // Simple Jet Quenching routine:
671 // =============================
672 // The jet formed by all final state partons radiated by the parton created
673 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
674 // the initial parton reference frame:
675 // (E + p_z)new = (1-z) (E + p_z)old
680 // The lost momentum is first balanced by one gluon with virtuality > 0.
681 // Subsequently the gluon splits to yield two gluons with E = p.
685 static Float_t eMean = 0.;
686 static Int_t icall = 0;
691 Int_t klast[4] = {-1, -1, -1, -1};
693 Int_t numpart = fPyjets->N;
694 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
695 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
703 // Sore information about Primary partons
706 // 0, 1 partons from hard scattering
707 // 2, 3 partons from initial state radiation
709 for (Int_t i = 2; i <= 7; i++) {
711 // Skip gluons that participate in hard scattering
712 if (i == 4 || i == 5) continue;
713 // Gluons from hard Scattering
714 if (i == 6 || i == 7) {
716 pxq[j] = fPyjets->P[0][i];
717 pyq[j] = fPyjets->P[1][i];
718 pzq[j] = fPyjets->P[2][i];
719 eq[j] = fPyjets->P[3][i];
720 mq[j] = fPyjets->P[4][i];
722 // Gluons from initial state radiation
724 // Obtain 4-momentum vector from difference between original parton and parton after gluon
725 // radiation. Energy is calculated independently because initial state radition does not
726 // conserve strictly momentum and energy for each partonic system independently.
728 // Not very clean. Should be improved !
732 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
733 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
734 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
735 mq[j] = fPyjets->P[4][i];
736 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
739 // Calculate some kinematic variables
741 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
742 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
743 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
744 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
745 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
746 qPdg[j] = fPyjets->K[1][i];
752 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
754 for (Int_t j = 0; j < 4; j++) {
756 // Quench only central jets and with E > 10.
760 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
761 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
763 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
766 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
772 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
773 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
775 // Fractional energy loss
776 fZQuench[j] = eloss / eq[j];
778 // Avoid complete loss
780 if (fZQuench[j] == 1.) fZQuench[j] = 0.97;
782 // Some debug printing
785 // 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",
786 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
788 // fZQuench[j] = 0.8;
789 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
792 quenched[j] = (fZQuench[j] > 0.01);
797 Double_t pNew[1000][4];
804 for (Int_t isys = 0; isys < 4; isys++) {
805 // Skip to next system if not quenched.
806 if (!quenched[isys]) continue;
808 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
809 if (nGluon[isys] > 30) nGluon[isys] = 30;
810 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
811 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
817 Double_t pg[4] = {0., 0., 0., 0.};
820 // Loop on radiation events
822 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
825 for (Int_t k = 0; k < 4; k++)
832 for (Int_t i = 0; i < numpart; i++)
834 imo = fPyjets->K[2][i];
835 kst = fPyjets->K[0][i];
836 pdg = fPyjets->K[1][i];
840 // Quarks and gluons only
841 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
842 // Particles from hard scattering only
844 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
845 Int_t imom = imo % 1000;
846 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
847 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
850 // Skip comment lines
851 if (kst != 1 && kst != 2) continue;
854 px = fPyjets->P[0][i];
855 py = fPyjets->P[1][i];
856 pz = fPyjets->P[2][i];
857 e = fPyjets->P[3][i];
858 m = fPyjets->P[4][i];
859 pt = TMath::Sqrt(px * px + py * py);
860 p = TMath::Sqrt(px * px + py * py + pz * pz);
861 phi = TMath::Pi() + TMath::ATan2(-py, -px);
862 theta = TMath::ATan2(pt, pz);
865 // Save 4-momentum sum for balancing
876 // Fractional energy loss
877 Double_t z = zquench[index];
880 // Don't fully quench radiated gluons
883 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
888 // printf("z: %d %f\n", imo, z);
895 // Transform into frame in which initial parton is along z-axis
897 TVector3 v(px, py, pz);
898 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
899 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
901 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
902 Double_t mt2 = jt * jt + m * m;
905 // Kinematic limit on z
907 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
909 // Change light-cone kinematics rel. to initial parton
911 Double_t eppzOld = e + pl;
912 Double_t empzOld = e - pl;
914 Double_t eppzNew = (1. - z) * eppzOld;
915 Double_t empzNew = empzOld - mt2 * z / eppzOld;
916 Double_t eNew = 0.5 * (eppzNew + empzNew);
917 Double_t plNew = 0.5 * (eppzNew - empzNew);
921 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
922 Double_t mt2New = eppzNew * empzNew;
923 if (mt2New < 1.e-8) mt2New = 0.;
925 if (m * m > mt2New) {
927 // This should not happen
929 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
932 jtNew = TMath::Sqrt(mt2New - m * m);
935 // If pT is to small (probably a leading massive particle) we scale only the energy
936 // This can cause negative masses of the radiated gluon
937 // Let's hope for the best ...
939 eNew = TMath::Sqrt(plNew * plNew + mt2);
943 // Calculate new px, py
945 Double_t pxNew = jtNew / jt * pxs;
946 Double_t pyNew = jtNew / jt * pys;
948 // Double_t dpx = pxs - pxNew;
949 // Double_t dpy = pys - pyNew;
950 // Double_t dpz = pl - plNew;
951 // Double_t de = e - eNew;
952 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
953 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
954 // printf("New mass (2) %e %e \n", pxNew, pyNew);
958 TVector3 w(pxNew, pyNew, plNew);
959 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
960 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
962 p1[index][0] += pxNew;
963 p1[index][1] += pyNew;
964 p1[index][2] += plNew;
965 p1[index][3] += eNew;
967 // Updated 4-momentum vectors
969 pNew[icount][0] = pxNew;
970 pNew[icount][1] = pyNew;
971 pNew[icount][2] = plNew;
972 pNew[icount][3] = eNew;
977 // Check if there was phase-space for quenching
980 if (icount == 0) quenched[isys] = kFALSE;
981 if (!quenched[isys]) break;
983 for (Int_t j = 0; j < 4; j++)
985 p2[isys][j] = p0[isys][j] - p1[isys][j];
987 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];
988 if (p2[isys][4] > 0.) {
989 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
992 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
993 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]);
994 if (p2[isys][4] < -0.01) {
995 printf("Negative mass squared !\n");
996 // Here we have to put the gluon back to mass shell
997 // This will lead to a small energy imbalance
999 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
1008 printf("zHeavy lowered to %f\n", zHeavy);
1009 if (zHeavy < 0.01) {
1010 printf("No success ! \n");
1012 quenched[isys] = kFALSE;
1016 } // iteration on z (while)
1018 // Update event record
1019 for (Int_t k = 0; k < icount; k++) {
1020 // 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] );
1021 fPyjets->P[0][kNew[k]] = pNew[k][0];
1022 fPyjets->P[1][kNew[k]] = pNew[k][1];
1023 fPyjets->P[2][kNew[k]] = pNew[k][2];
1024 fPyjets->P[3][kNew[k]] = pNew[k][3];
1031 if (!quenched[isys]) continue;
1033 // Last parton from shower i
1034 Int_t in = klast[isys];
1036 // Continue if no parton in shower i selected
1037 if (in == -1) continue;
1039 // If this is the second initial parton and it is behind the first move pointer by previous ish
1040 if (isys == 1 && klast[1] > klast[0]) in += ish;
1045 // How many additional gluons will be generated
1047 if (p2[isys][4] > 0.05) ish = 2;
1049 // Position of gluons
1051 if (iglu == 0) igMin = iGlu;
1054 (fPyjets->N) += ish;
1057 fPyjets->P[0][iGlu] = p2[isys][0];
1058 fPyjets->P[1][iGlu] = p2[isys][1];
1059 fPyjets->P[2][iGlu] = p2[isys][2];
1060 fPyjets->P[3][iGlu] = p2[isys][3];
1061 fPyjets->P[4][iGlu] = p2[isys][4];
1063 fPyjets->K[0][iGlu] = 1;
1064 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1065 fPyjets->K[1][iGlu] = 21;
1066 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1067 fPyjets->K[3][iGlu] = -1;
1068 fPyjets->K[4][iGlu] = -1;
1070 pg[0] += p2[isys][0];
1071 pg[1] += p2[isys][1];
1072 pg[2] += p2[isys][2];
1073 pg[3] += p2[isys][3];
1076 // Split gluon in rest frame.
1078 Double_t bx = p2[isys][0] / p2[isys][3];
1079 Double_t by = p2[isys][1] / p2[isys][3];
1080 Double_t bz = p2[isys][2] / p2[isys][3];
1081 Double_t pst = p2[isys][4] / 2.;
1083 // Isotropic decay ????
1084 Double_t cost = 2. * gRandom->Rndm() - 1.;
1085 Double_t sint = TMath::Sqrt(1. - cost * cost);
1086 Double_t phi = 2. * TMath::Pi() * gRandom->Rndm();
1088 Double_t pz1 = pst * cost;
1089 Double_t pz2 = -pst * cost;
1090 Double_t pt1 = pst * sint;
1091 Double_t pt2 = -pst * sint;
1092 Double_t px1 = pt1 * TMath::Cos(phi);
1093 Double_t py1 = pt1 * TMath::Sin(phi);
1094 Double_t px2 = pt2 * TMath::Cos(phi);
1095 Double_t py2 = pt2 * TMath::Sin(phi);
1097 fPyjets->P[0][iGlu] = px1;
1098 fPyjets->P[1][iGlu] = py1;
1099 fPyjets->P[2][iGlu] = pz1;
1100 fPyjets->P[3][iGlu] = pst;
1101 fPyjets->P[4][iGlu] = 0.;
1103 fPyjets->K[0][iGlu] = 1 ;
1104 fPyjets->K[1][iGlu] = 21;
1105 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1106 fPyjets->K[3][iGlu] = -1;
1107 fPyjets->K[4][iGlu] = -1;
1109 fPyjets->P[0][iGlu+1] = px2;
1110 fPyjets->P[1][iGlu+1] = py2;
1111 fPyjets->P[2][iGlu+1] = pz2;
1112 fPyjets->P[3][iGlu+1] = pst;
1113 fPyjets->P[4][iGlu+1] = 0.;
1115 fPyjets->K[0][iGlu+1] = 1;
1116 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1117 fPyjets->K[1][iGlu+1] = 21;
1118 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1119 fPyjets->K[3][iGlu+1] = -1;
1120 fPyjets->K[4][iGlu+1] = -1;
1126 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1129 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1130 Double_t px, py, pz;
1131 px = fPyjets->P[0][ig];
1132 py = fPyjets->P[1][ig];
1133 pz = fPyjets->P[2][ig];
1134 TVector3 v(px, py, pz);
1135 v.RotateZ(-phiq[isys]);
1136 v.RotateY(-thetaq[isys]);
1137 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1138 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1139 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1140 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1141 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1142 pxs += jtKick * TMath::Cos(phiKick);
1143 pys += jtKick * TMath::Sin(phiKick);
1144 TVector3 w(pxs, pys, pzs);
1145 w.RotateY(thetaq[isys]);
1146 w.RotateZ(phiq[isys]);
1147 fPyjets->P[0][ig] = w.X();
1148 fPyjets->P[1][ig] = w.Y();
1149 fPyjets->P[2][ig] = w.Z();
1150 fPyjets->P[2][ig] = w.Mag();
1156 // Check energy conservation
1160 Double_t es = 14000.;
1162 for (Int_t i = 0; i < numpart; i++)
1164 kst = fPyjets->K[0][i];
1165 if (kst != 1 && kst != 2) continue;
1166 pxs += fPyjets->P[0][i];
1167 pys += fPyjets->P[1][i];
1168 pzs += fPyjets->P[2][i];
1169 es -= fPyjets->P[3][i];
1171 if (TMath::Abs(pxs) > 1.e-2 ||
1172 TMath::Abs(pys) > 1.e-2 ||
1173 TMath::Abs(pzs) > 1.e-1) {
1174 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1175 // Fatal("Quench()", "4-Momentum non-conservation");
1178 } // end quenching loop (systems)
1180 for (Int_t i = 0; i < numpart; i++)
1182 imo = fPyjets->K[2][i];
1184 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1191 void AliPythia::Pyquen(Double_t a, Int_t ibf, Double_t b)
1193 // Igor Lokthine's quenching routine
1197 void AliPythia::Pyevnw()
1199 // New multiple interaction scenario
1203 void AliPythia::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1205 // Return event specific quenching parameters
1208 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];
1212 void AliPythia::ConfigHeavyFlavor()
1215 // Default configuration for Heavy Flavor production
1217 // All QCD processes
1221 // No multiple interactions
1225 // Initial/final parton shower on (Pythia default)
1229 // 2nd order alpha_s
1237 void AliPythia::AtlasTuning()
1240 // Configuration for the ATLAS tuning
1241 SetMSTP(51, kCTEQ5L); // CTEQ5L pdf
1242 SetMSTP(81,1); // Multiple Interactions ON
1243 SetMSTP(82,4); // Double Gaussian Model
1244 SetPARP(81,1.9); // Min. pt for multiple interactions (default in 6.2-14)
1245 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
1246 SetPARP(89,1000.); // [GeV] Ref. energy
1247 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
1248 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
1249 SetPARP(84,0.5); // Core radius
1250 SetPARP(85,0.33); // Regulates gluon prod. mechanism
1251 SetPARP(86,0.66); // Regulates gluon prod. mechanism
1252 SetPARP(67,1); // Regulates Initial State Radiation
1255 AliPythia& AliPythia::operator=(const AliPythia& rhs)
1257 // Assignment operator
1262 void AliPythia::Copy(TObject&) const
1267 Fatal("Copy","Not implemented!\n");