1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
18 #include "AliPythia.h"
19 #include "AliPythiaRndm.h"
20 #include "../FASTSIM/AliFastGlauber.h"
21 #include "../FASTSIM/AliQuenchingWeights.h"
27 # define pyclus pyclus_
28 # define pycell pycell_
29 # define pyshow pyshow_
30 # define pyrobo pyrobo_
31 # define pyquen pyquen_
32 # define pyevnw pyevnw_
35 # define pyclus PYCLUS
36 # define pycell PYCELL
37 # define pyrobo PYROBO
38 # define pyquen PYQUEN
39 # define pyevnw PYEVNW
40 # define type_of_call _stdcall
43 extern "C" void type_of_call pyclus(Int_t & );
44 extern "C" void type_of_call pycell(Int_t & );
45 extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
46 extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
47 extern "C" void type_of_call pyquen(Double_t &, Int_t &, Double_t &);
48 extern "C" void type_of_call pyevnw(){;}
50 //_____________________________________________________________________________
52 AliPythia* AliPythia::fgAliPythia=NULL;
54 AliPythia::AliPythia()
56 // Default Constructor
59 if (!AliPythiaRndm::GetPythiaRandom())
60 AliPythiaRndm::SetPythiaRandom(GetRandom());
62 fQuenchingWeights = 0;
65 void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc)
67 // Initialise the process to generate
68 if (!AliPythiaRndm::GetPythiaRandom())
69 AliPythiaRndm::SetPythiaRandom(GetRandom());
73 fStrucFunc = strucfunc;
74 //...Switch off decay of pi0, K0S, Lambda, Sigma+-, Xi0-, Omega-.
75 SetMDCY(Pycomp(111) ,1,0);
76 SetMDCY(Pycomp(310) ,1,0);
77 SetMDCY(Pycomp(3122),1,0);
78 SetMDCY(Pycomp(3112),1,0);
79 SetMDCY(Pycomp(3212),1,0);
80 SetMDCY(Pycomp(3222),1,0);
81 SetMDCY(Pycomp(3312),1,0);
82 SetMDCY(Pycomp(3322),1,0);
83 SetMDCY(Pycomp(3334),1,0);
84 // Select structure function
86 SetMSTP(51,strucfunc);
87 // Particles produced in string fragmentation point directly to either of the two endpoints
88 // of the string (depending in the side they were generated from).
92 // Pythia initialisation for selected processes//
96 for (Int_t i=1; i<= 200; i++) {
99 // select charm production
102 case kPyOldUEQ2ordered: //Old underlying events with Q2 ordered QCD processes
103 // Multiple interactions on.
105 // Double Gaussian matter distribution.
111 // Reference energy for pT0 and energy rescaling pace.
114 // String drawing almost completely minimizes string length.
117 // ISR and FSR activity.
123 case kPyOldUEQ2ordered2:
124 // Old underlying events with Q2 ordered QCD processes
125 // Multiple interactions on.
127 // Double Gaussian matter distribution.
133 // Reference energy for pT0 and energy rescaling pace.
135 SetPARP(90,0.16); // here is the difference with kPyOldUEQ2ordered
136 // String drawing almost completely minimizes string length.
139 // ISR and FSR activity.
146 // Old production mechanism: Old Popcorn
149 // (D=2) Like MSTJ(12)=2 but added prod ofthe 1er rank baryon
151 // (D=1)see can be used to form baryons (BARYON JUNCTION)
157 // heavy quark masses
187 case kPyCharmUnforced:
196 case kPyBeautyUnforced:
206 // Minimum Bias pp-Collisions
209 // select Pythia min. bias model
211 SetMSUB(92,1); // single diffraction AB-->XB
212 SetMSUB(93,1); // single diffraction AB-->AX
213 SetMSUB(94,1); // double diffraction
214 SetMSUB(95,1); // low pt production
219 // Minimum Bias pp-Collisions
222 // select Pythia min. bias model
224 SetMSUB(95,1); // low pt production
231 SetMSTP(91,1);// Width (1=gaussian) primordial kT dist. inside hadrons
232 SetPARP(91,1.); // <kT^2> = PARP(91,1.)^2
233 SetPARP(93,5.); // Upper cut-off
235 SetPMAS(4,1,1.2); // Charm quark mass
236 SetPMAS(5,1,4.78); // Beauty quark mass
237 SetPARP(71,4.); // Defaut value
246 // Pythia Tune A (CDF)
248 SetPARP(67,4.); // Regulates Initial State Radiation
249 SetMSTP(82,4); // Double Gaussian Model
250 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
251 SetPARP(84,0.4); // Core radius
252 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
253 SetPARP(86,0.95); // Regulates gluon prod. mechanism
254 SetPARP(89,1800.); // [GeV] Ref. energy
255 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
260 case kPyCharmPbPbMNR:
262 case kPyDPlusPbPbMNR:
263 case kPyDPlusStrangePbPbMNR:
264 // Tuning of Pythia parameters aimed to get a resonable agreement
265 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
266 // c-cbar single inclusive and double differential distributions.
267 // This parameter settings are meant to work with Pb-Pb collisions
268 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
269 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
270 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
282 case kPyDPlusStrangepPbMNR:
283 // Tuning of Pythia parameters aimed to get a resonable agreement
284 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
285 // c-cbar single inclusive and double differential distributions.
286 // This parameter settings are meant to work with p-Pb collisions
287 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
288 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
289 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
302 case kPyDPlusStrangeppMNR:
303 // Tuning of Pythia parameters aimed to get a resonable agreement
304 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
305 // c-cbar single inclusive and double differential distributions.
306 // This parameter settings are meant to work with pp collisions
307 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
308 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
309 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
319 case kPyCharmppMNRwmi:
320 // Tuning of Pythia parameters aimed to get a resonable agreement
321 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
322 // c-cbar single inclusive and double differential distributions.
323 // This parameter settings are meant to work with pp collisions
324 // and with kCTEQ5L PDFs.
325 // Added multiple interactions according to ATLAS tune settings.
326 // To get a "reasonable" agreement with MNR results, events have to be
327 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
329 // To get a "perfect" agreement with MNR results, events have to be
330 // generated in four ptHard bins with the following relative
346 case kPyBeautyPbPbMNR:
347 // Tuning of Pythia parameters aimed to get a resonable agreement
348 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
349 // b-bbar single inclusive and double differential distributions.
350 // This parameter settings are meant to work with Pb-Pb collisions
351 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
352 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
353 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
365 case kPyBeautypPbMNR:
366 // Tuning of Pythia parameters aimed to get a resonable agreement
367 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
368 // b-bbar single inclusive and double differential distributions.
369 // This parameter settings are meant to work with p-Pb collisions
370 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
371 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
372 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
385 // Tuning of Pythia parameters aimed to get a resonable agreement
386 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
387 // b-bbar single inclusive and double differential distributions.
388 // This parameter settings are meant to work with pp collisions
389 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
390 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
391 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
405 case kPyBeautyppMNRwmi:
406 // Tuning of Pythia parameters aimed to get a resonable agreement
407 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
408 // b-bbar single inclusive and double differential distributions.
409 // This parameter settings are meant to work with pp collisions
410 // and with kCTEQ5L PDFs.
411 // Added multiple interactions according to ATLAS tune settings.
412 // To get a "reasonable" agreement with MNR results, events have to be
413 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
415 // To get a "perfect" agreement with MNR results, events have to be
416 // generated in four ptHard bins with the following relative
439 //Inclusive production of W+/-
445 // //f fbar -> gamma W+
452 // Initial/final parton shower on (Pythia default)
453 // With parton showers on we are generating "W inclusive process"
454 SetMSTP(61,1); //Initial QCD & QED showers on
455 SetMSTP(71,1); //Final QCD & QED showers on
461 //Inclusive production of Z
466 // // f fbar -> g Z/gamma
468 // // f fbar -> gamma Z/gamma
470 // // f g -> f Z/gamma
472 // // f gamma -> f Z/gamma
475 //only Z included, not gamma
478 // Initial/final parton shower on (Pythia default)
479 // With parton showers on we are generating "Z inclusive process"
480 SetMSTP(61,1); //Initial QCD & QED showers on
481 SetMSTP(71,1); //Final QCD & QED showers on
488 SetMSTP(41,1); // all resonance decays switched on
490 Initialize("CMS","p","p",fEcms);
494 Int_t AliPythia::CheckedLuComp(Int_t kf)
496 // Check Lund particle code (for debugging)
498 printf("\n Lucomp kf,kc %d %d",kf,kc);
502 void AliPythia::SetNuclei(Int_t a1, Int_t a2)
504 // Treat protons as inside nuclei with mass numbers a1 and a2
505 // The MSTP array in the PYPARS common block is used to enable and
506 // select the nuclear structure functions.
507 // MSTP(52) : (D=1) choice of proton and nuclear structure-function library
508 // =1: internal PYTHIA acording to MSTP(51)
509 // =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
510 // If the following mass number both not equal zero, nuclear corrections of the stf are used.
511 // MSTP(192) : Mass number of nucleus side 1
512 // MSTP(193) : Mass number of nucleus side 2
519 AliPythia* AliPythia::Instance()
521 // Set random number generator
525 fgAliPythia = new AliPythia();
530 void AliPythia::PrintParticles()
532 // Print list of particl properties
534 char* name = new char[16];
535 for (Int_t kf=0; kf<1000000; kf++) {
536 for (Int_t c = 1; c > -2; c-=2) {
537 Int_t kc = Pycomp(c*kf);
539 Float_t mass = GetPMAS(kc,1);
540 Float_t width = GetPMAS(kc,2);
541 Float_t tau = GetPMAS(kc,4);
547 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
548 c*kf, name, mass, width, tau);
552 printf("\n Number of particles %d \n \n", np);
555 void AliPythia::ResetDecayTable()
557 // Set default values for pythia decay switches
559 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
560 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
563 void AliPythia::SetDecayTable()
565 // Set default values for pythia decay switches
568 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
569 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
572 void AliPythia::Pyclus(Int_t& njet)
574 // Call Pythia clustering algorithm
579 void AliPythia::Pycell(Int_t& njet)
581 // Call Pythia jet reconstruction algorithm
586 void AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
588 // Call Pythia jet reconstruction algorithm
590 pyshow(ip1, ip2, qmax);
593 void AliPythia::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
595 pyrobo(imi, ima, the, phi, bex, bey, bez);
600 void AliPythia::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod)
603 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
604 // (2) The nuclear geometry using the Glauber Model
608 fGlauber = new AliFastGlauber();
610 fGlauber->SetCentralityClass(cMin, cMax);
612 fQuenchingWeights = new AliQuenchingWeights();
613 fQuenchingWeights->InitMult();
614 fQuenchingWeights->SetK(k);
615 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
619 void AliPythia::Quench()
623 // Simple Jet Quenching routine:
624 // =============================
625 // The jet formed by all final state partons radiated by the parton created
626 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
627 // the initial parton reference frame:
628 // (E + p_z)new = (1-z) (E + p_z)old
633 // The lost momentum is first balanced by one gluon with virtuality > 0.
634 // Subsequently the gluon splits to yield two gluons with E = p.
638 static Float_t eMean = 0.;
639 static Int_t icall = 0;
644 Int_t klast[4] = {-1, -1, -1, -1};
646 Int_t numpart = fPyjets->N;
647 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
648 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
656 // Sore information about Primary partons
659 // 0, 1 partons from hard scattering
660 // 2, 3 partons from initial state radiation
662 for (Int_t i = 2; i <= 7; i++) {
664 // Skip gluons that participate in hard scattering
665 if (i == 4 || i == 5) continue;
666 // Gluons from hard Scattering
667 if (i == 6 || i == 7) {
669 pxq[j] = fPyjets->P[0][i];
670 pyq[j] = fPyjets->P[1][i];
671 pzq[j] = fPyjets->P[2][i];
672 eq[j] = fPyjets->P[3][i];
673 mq[j] = fPyjets->P[4][i];
675 // Gluons from initial state radiation
677 // Obtain 4-momentum vector from difference between original parton and parton after gluon
678 // radiation. Energy is calculated independently because initial state radition does not
679 // conserve strictly momentum and energy for each partonic system independently.
681 // Not very clean. Should be improved !
685 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
686 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
687 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
688 mq[j] = fPyjets->P[4][i];
689 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
692 // Calculate some kinematic variables
694 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
695 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
696 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
697 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
698 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
699 qPdg[j] = fPyjets->K[1][i];
705 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
707 for (Int_t j = 0; j < 4; j++) {
709 // Quench only central jets and with E > 10.
713 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
714 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
716 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
719 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
725 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
726 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
728 // Fractional energy loss
729 fZQuench[j] = eloss / eq[j];
731 // Avoid complete loss
733 if (fZQuench[j] == 1.) fZQuench[j] = 0.95;
735 // Some debug printing
738 // 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",
739 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
741 // fZQuench[j] = 0.8;
742 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
745 quenched[j] = (fZQuench[j] > 0.01);
750 Double_t pNew[1000][4];
757 for (Int_t isys = 0; isys < 4; isys++) {
758 // Skip to next system if not quenched.
759 if (!quenched[isys]) continue;
761 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
762 if (nGluon[isys] > 6) nGluon[isys] = 6;
763 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
764 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
770 Double_t pg[4] = {0., 0., 0., 0.};
773 // Loop on radiation events
775 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
778 for (Int_t k = 0; k < 4; k++)
785 for (Int_t i = 0; i < numpart; i++)
787 imo = fPyjets->K[2][i];
788 kst = fPyjets->K[0][i];
789 pdg = fPyjets->K[1][i];
793 // Quarks and gluons only
794 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
795 // Particles from hard scattering only
797 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
798 Int_t imom = imo % 1000;
799 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
800 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
803 // Skip comment lines
804 if (kst != 1 && kst != 2) continue;
807 px = fPyjets->P[0][i];
808 py = fPyjets->P[1][i];
809 pz = fPyjets->P[2][i];
810 e = fPyjets->P[3][i];
811 m = fPyjets->P[4][i];
812 pt = TMath::Sqrt(px * px + py * py);
813 p = TMath::Sqrt(px * px + py * py + pz * pz);
814 phi = TMath::Pi() + TMath::ATan2(-py, -px);
815 theta = TMath::ATan2(pt, pz);
818 // Save 4-momentum sum for balancing
829 // Fractional energy loss
830 Double_t z = zquench[index];
833 // Don't fully quench radiated gluons
836 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
841 // printf("z: %d %f\n", imo, z);
848 // Transform into frame in which initial parton is along z-axis
850 TVector3 v(px, py, pz);
851 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
852 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
854 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
855 Double_t mt2 = jt * jt + m * m;
858 // Kinematic limit on z
860 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
862 // Change light-cone kinematics rel. to initial parton
864 Double_t eppzOld = e + pl;
865 Double_t empzOld = e - pl;
867 Double_t eppzNew = (1. - z) * eppzOld;
868 Double_t empzNew = empzOld - mt2 * z / eppzOld;
869 Double_t eNew = 0.5 * (eppzNew + empzNew);
870 Double_t plNew = 0.5 * (eppzNew - empzNew);
874 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
875 Double_t mt2New = eppzNew * empzNew;
876 if (mt2New < 1.e-8) mt2New = 0.;
878 if (m * m > mt2New) {
880 // This should not happen
882 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
885 jtNew = TMath::Sqrt(mt2New - m * m);
888 // If pT is to small (probably a leading massive particle) we scale only the energy
889 // This can cause negative masses of the radiated gluon
890 // Let's hope for the best ...
892 eNew = TMath::Sqrt(plNew * plNew + mt2);
896 // Calculate new px, py
898 Double_t pxNew = jtNew / jt * pxs;
899 Double_t pyNew = jtNew / jt * pys;
901 // Double_t dpx = pxs - pxNew;
902 // Double_t dpy = pys - pyNew;
903 // Double_t dpz = pl - plNew;
904 // Double_t de = e - eNew;
905 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
906 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
907 // printf("New mass (2) %e %e \n", pxNew, pyNew);
911 TVector3 w(pxNew, pyNew, plNew);
912 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
913 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
915 p1[index][0] += pxNew;
916 p1[index][1] += pyNew;
917 p1[index][2] += plNew;
918 p1[index][3] += eNew;
920 // Updated 4-momentum vectors
922 pNew[icount][0] = pxNew;
923 pNew[icount][1] = pyNew;
924 pNew[icount][2] = plNew;
925 pNew[icount][3] = eNew;
930 // Check if there was phase-space for quenching
933 if (icount == 0) quenched[isys] = kFALSE;
934 if (!quenched[isys]) break;
936 for (Int_t j = 0; j < 4; j++)
938 p2[isys][j] = p0[isys][j] - p1[isys][j];
940 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];
941 if (p2[isys][4] > 0.) {
942 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
945 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
946 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]);
947 if (p2[isys][4] < -0.01) {
948 printf("Negative mass squared !\n");
949 // Here we have to put the gluon back to mass shell
950 // This will lead to a small energy imbalance
952 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
961 printf("zHeavy lowered to %f\n", zHeavy);
963 printf("No success ! \n");
965 quenched[isys] = kFALSE;
969 } // iteration on z (while)
971 // Update event record
972 for (Int_t k = 0; k < icount; k++) {
973 // 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] );
974 fPyjets->P[0][kNew[k]] = pNew[k][0];
975 fPyjets->P[1][kNew[k]] = pNew[k][1];
976 fPyjets->P[2][kNew[k]] = pNew[k][2];
977 fPyjets->P[3][kNew[k]] = pNew[k][3];
984 if (!quenched[isys]) continue;
986 // Last parton from shower i
987 Int_t in = klast[isys];
989 // Continue if no parton in shower i selected
990 if (in == -1) continue;
992 // If this is the second initial parton and it is behind the first move pointer by previous ish
993 if (isys == 1 && klast[1] > klast[0]) in += ish;
998 // How many additional gluons will be generated
1000 if (p2[isys][4] > 0.05) ish = 2;
1002 // Position of gluons
1004 if (iglu == 0) igMin = iGlu;
1007 (fPyjets->N) += ish;
1010 fPyjets->P[0][iGlu] = p2[isys][0];
1011 fPyjets->P[1][iGlu] = p2[isys][1];
1012 fPyjets->P[2][iGlu] = p2[isys][2];
1013 fPyjets->P[3][iGlu] = p2[isys][3];
1014 fPyjets->P[4][iGlu] = p2[isys][4];
1016 fPyjets->K[0][iGlu] = 1;
1017 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1018 fPyjets->K[1][iGlu] = 21;
1019 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1020 fPyjets->K[3][iGlu] = -1;
1021 fPyjets->K[4][iGlu] = -1;
1023 pg[0] += p2[isys][0];
1024 pg[1] += p2[isys][1];
1025 pg[2] += p2[isys][2];
1026 pg[3] += p2[isys][3];
1029 // Split gluon in rest frame.
1031 Double_t bx = p2[isys][0] / p2[isys][3];
1032 Double_t by = p2[isys][1] / p2[isys][3];
1033 Double_t bz = p2[isys][2] / p2[isys][3];
1034 Double_t pst = p2[isys][4] / 2.;
1036 // Isotropic decay ????
1037 Double_t cost = 2. * gRandom->Rndm() - 1.;
1038 Double_t sint = TMath::Sqrt(1. - cost * cost);
1039 Double_t phi = 2. * TMath::Pi() * gRandom->Rndm();
1041 Double_t pz1 = pst * cost;
1042 Double_t pz2 = -pst * cost;
1043 Double_t pt1 = pst * sint;
1044 Double_t pt2 = -pst * sint;
1045 Double_t px1 = pt1 * TMath::Cos(phi);
1046 Double_t py1 = pt1 * TMath::Sin(phi);
1047 Double_t px2 = pt2 * TMath::Cos(phi);
1048 Double_t py2 = pt2 * TMath::Sin(phi);
1050 fPyjets->P[0][iGlu] = px1;
1051 fPyjets->P[1][iGlu] = py1;
1052 fPyjets->P[2][iGlu] = pz1;
1053 fPyjets->P[3][iGlu] = pst;
1054 fPyjets->P[4][iGlu] = 0.;
1056 fPyjets->K[0][iGlu] = 1 ;
1057 fPyjets->K[1][iGlu] = 21;
1058 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1059 fPyjets->K[3][iGlu] = -1;
1060 fPyjets->K[4][iGlu] = -1;
1062 fPyjets->P[0][iGlu+1] = px2;
1063 fPyjets->P[1][iGlu+1] = py2;
1064 fPyjets->P[2][iGlu+1] = pz2;
1065 fPyjets->P[3][iGlu+1] = pst;
1066 fPyjets->P[4][iGlu+1] = 0.;
1068 fPyjets->K[0][iGlu+1] = 1;
1069 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1070 fPyjets->K[1][iGlu+1] = 21;
1071 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1072 fPyjets->K[3][iGlu+1] = -1;
1073 fPyjets->K[4][iGlu+1] = -1;
1079 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1082 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1083 Double_t px, py, pz;
1084 px = fPyjets->P[0][ig];
1085 py = fPyjets->P[1][ig];
1086 pz = fPyjets->P[2][ig];
1087 TVector3 v(px, py, pz);
1088 v.RotateZ(-phiq[isys]);
1089 v.RotateY(-thetaq[isys]);
1090 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1091 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1092 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1093 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1094 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1095 pxs += jtKick * TMath::Cos(phiKick);
1096 pys += jtKick * TMath::Sin(phiKick);
1097 TVector3 w(pxs, pys, pzs);
1098 w.RotateY(thetaq[isys]);
1099 w.RotateZ(phiq[isys]);
1100 fPyjets->P[0][ig] = w.X();
1101 fPyjets->P[1][ig] = w.Y();
1102 fPyjets->P[2][ig] = w.Z();
1103 fPyjets->P[2][ig] = w.Mag();
1109 // Check energy conservation
1113 Double_t es = 14000.;
1115 for (Int_t i = 0; i < numpart; i++)
1117 kst = fPyjets->K[0][i];
1118 if (kst != 1 && kst != 2) continue;
1119 pxs += fPyjets->P[0][i];
1120 pys += fPyjets->P[1][i];
1121 pzs += fPyjets->P[2][i];
1122 es -= fPyjets->P[3][i];
1124 if (TMath::Abs(pxs) > 1.e-2 ||
1125 TMath::Abs(pys) > 1.e-2 ||
1126 TMath::Abs(pzs) > 1.e-1) {
1127 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1128 // Fatal("Quench()", "4-Momentum non-conservation");
1131 } // end quenching loop (systems)
1133 for (Int_t i = 0; i < numpart; i++)
1135 imo = fPyjets->K[2][i];
1137 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1144 void AliPythia::Pyquen(Double_t a, Int_t ibf, Double_t b)
1146 // Igor Lokthine's quenching routine
1150 void AliPythia::Pyevnw()
1152 // New multiple interaction scenario
1156 void AliPythia::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1158 // Return event specific quenching parameters
1161 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];
1165 void AliPythia::ConfigHeavyFlavor()
1168 // Default configuration for Heavy Flavor production
1170 // All QCD processes
1174 // No multiple interactions
1176 // Initial/final parton shower on (Pythia default)
1180 // 2nd order alpha_s
1188 void AliPythia::AtlasTuning()
1191 // Configuration for the ATLAS tuning
1192 SetMSTP(51, kCTEQ5L); // CTEQ5L pdf
1193 SetMSTP(81,1); // Multiple Interactions ON
1194 SetMSTP(82,4); // Double Gaussian Model
1195 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
1196 SetPARP(89,1000.); // [GeV] Ref. energy
1197 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
1198 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
1199 SetPARP(84,0.5); // Core radius
1200 SetPARP(85,0.33); // Regulates gluon prod. mechanism
1201 SetPARP(86,0.66); // Regulates gluon prod. mechanism
1202 SetPARP(67,1); // Regulates Initial State Radiation