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
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
265 // Les Houches Working Group 05 Minimum Bias pp-Collisions: hep-ph/0604120
266 // -> Pythia 6.3 or above is needed
269 SetMSUB(92,1); // single diffraction AB-->XB
270 SetMSUB(93,1); // single diffraction AB-->AX
271 SetMSUB(94,1); // double diffraction
272 SetMSUB(95,1); // low pt production
273 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ6ll));
277 SetMSTP(81,1); // Multiple Interactions ON
278 SetMSTP(82,4); // Double Gaussian Model
281 SetPARP(82,2.3); // [GeV] PT_min at Ref. energy
282 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
283 SetPARP(84,0.5); // Core radius
284 SetPARP(85,0.9); // Regulates gluon prod. mechanism
285 SetPARP(90,0.2); // 2*epsilon (exponent in power law)
289 // Minimum Bias pp-Collisions
292 // select Pythia min. bias model
294 SetMSUB(95,1); // low pt production
301 SetMSTP(91,1);// Width (1=gaussian) primordial kT dist. inside hadrons
302 SetPARP(91,1.); // <kT^2> = PARP(91,1.)^2
303 SetPARP(93,5.); // Upper cut-off
305 SetPMAS(4,1,1.2); // Charm quark mass
306 SetPMAS(5,1,4.78); // Beauty quark mass
307 SetPARP(71,4.); // Defaut value
316 // Pythia Tune A (CDF)
318 SetPARP(67,2.5); // Regulates Initial State Radiation (value from best fit to D0 dijet analysis)
319 SetMSTP(82,4); // Double Gaussian Model
320 SetPARP(82,2.0); // [GeV] PT_min at Ref. energy
321 SetPARP(84,0.4); // Core radius
322 SetPARP(85,0.90) ; // Regulates gluon prod. mechanism
323 SetPARP(86,0.95); // Regulates gluon prod. mechanism
324 SetPARP(89,1800.); // [GeV] Ref. energy
325 SetPARP(90,0.25); // 2*epsilon (exponent in power law)
330 case kPyCharmPbPbMNR:
332 case kPyDPlusPbPbMNR:
333 case kPyDPlusStrangePbPbMNR:
334 // Tuning of Pythia parameters aimed to get a resonable agreement
335 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
336 // c-cbar single inclusive and double differential distributions.
337 // This parameter settings are meant to work with Pb-Pb collisions
338 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
339 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
340 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
352 case kPyDPlusStrangepPbMNR:
353 // Tuning of Pythia parameters aimed to get a resonable agreement
354 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
355 // c-cbar single inclusive and double differential distributions.
356 // This parameter settings are meant to work with p-Pb collisions
357 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
358 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
359 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
372 case kPyDPlusStrangeppMNR:
373 // Tuning of Pythia parameters aimed to get a resonable agreement
374 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
375 // c-cbar single inclusive and double differential distributions.
376 // This parameter settings are meant to work with pp collisions
377 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
378 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
379 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
389 case kPyCharmppMNRwmi:
390 // Tuning of Pythia parameters aimed to get a resonable agreement
391 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
392 // c-cbar single inclusive and double differential distributions.
393 // This parameter settings are meant to work with pp collisions
394 // and with kCTEQ5L PDFs.
395 // Added multiple interactions according to ATLAS tune settings.
396 // To get a "reasonable" agreement with MNR results, events have to be
397 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
399 // To get a "perfect" agreement with MNR results, events have to be
400 // generated in four ptHard bins with the following relative
416 case kPyBeautyPbPbMNR:
417 // Tuning of Pythia parameters aimed to get a resonable agreement
418 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
419 // b-bbar single inclusive and double differential distributions.
420 // This parameter settings are meant to work with Pb-Pb collisions
421 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
422 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
423 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
435 case kPyBeautypPbMNR:
436 // Tuning of Pythia parameters aimed to get a resonable agreement
437 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
438 // b-bbar single inclusive and double differential distributions.
439 // This parameter settings are meant to work with p-Pb collisions
440 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
441 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
442 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
455 // Tuning of Pythia parameters aimed to get a resonable agreement
456 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
457 // b-bbar single inclusive and double differential distributions.
458 // This parameter settings are meant to work with pp collisions
459 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
460 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
461 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
475 case kPyBeautyppMNRwmi:
476 // Tuning of Pythia parameters aimed to get a resonable agreement
477 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
478 // b-bbar single inclusive and double differential distributions.
479 // This parameter settings are meant to work with pp collisions
480 // and with kCTEQ5L PDFs.
481 // Added multiple interactions according to ATLAS tune settings.
482 // To get a "reasonable" agreement with MNR results, events have to be
483 // generated with the minimum ptHard (AliGenPythia::SetPtHard)
485 // To get a "perfect" agreement with MNR results, events have to be
486 // generated in four ptHard bins with the following relative
509 //Inclusive production of W+/-
515 // //f fbar -> gamma W+
522 // Initial/final parton shower on (Pythia default)
523 // With parton showers on we are generating "W inclusive process"
524 SetMSTP(61,1); //Initial QCD & QED showers on
525 SetMSTP(71,1); //Final QCD & QED showers on
531 //Inclusive production of Z
536 // // f fbar -> g Z/gamma
538 // // f fbar -> gamma Z/gamma
540 // // f g -> f Z/gamma
542 // // f gamma -> f Z/gamma
545 //only Z included, not gamma
548 // Initial/final parton shower on (Pythia default)
549 // With parton showers on we are generating "Z inclusive process"
550 SetMSTP(61,1); //Initial QCD & QED showers on
551 SetMSTP(71,1); //Final QCD & QED showers on
558 SetMSTP(41,1); // all resonance decays switched on
559 Initialize("CMS","p","p",fEcms);
563 Int_t AliPythia6::CheckedLuComp(Int_t kf)
565 // Check Lund particle code (for debugging)
570 void AliPythia6::SetNuclei(Int_t a1, Int_t a2)
572 // Treat protons as inside nuclei with mass numbers a1 and a2
573 // The MSTP array in the PYPARS common block is used to enable and
574 // select the nuclear structure functions.
575 // MSTP(52) : (D=1) choice of proton and nuclear structure-function library
576 // =1: internal PYTHIA acording to MSTP(51)
577 // =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
578 // If the following mass number both not equal zero, nuclear corrections of the stf are used.
579 // MSTP(192) : Mass number of nucleus side 1
580 // MSTP(193) : Mass number of nucleus side 2
587 AliPythia6* AliPythia6::Instance()
589 // Set random number generator
593 fgAliPythia = new AliPythia6();
598 void AliPythia6::PrintParticles()
600 // Print list of particl properties
602 char* name = new char[16];
603 for (Int_t kf=0; kf<1000000; kf++) {
604 for (Int_t c = 1; c > -2; c-=2) {
605 Int_t kc = Pycomp(c*kf);
607 Float_t mass = GetPMAS(kc,1);
608 Float_t width = GetPMAS(kc,2);
609 Float_t tau = GetPMAS(kc,4);
615 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
616 c*kf, name, mass, width, tau);
620 printf("\n Number of particles %d \n \n", np);
623 void AliPythia6::ResetDecayTable()
625 // Set default values for pythia decay switches
627 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
628 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
631 void AliPythia6::SetDecayTable()
633 // Set default values for pythia decay switches
636 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
637 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
640 void AliPythia6::Pyclus(Int_t& njet)
642 // Call Pythia clustering algorithm
647 void AliPythia6::Pycell(Int_t& njet)
649 // Call Pythia jet reconstruction algorithm
654 void AliPythia6::GetJet(Int_t i, Float_t& px, Float_t& py, Float_t& pz, Float_t& e)
658 px = GetPyjets()->P[0][n+i];
659 py = GetPyjets()->P[1][n+i];
660 pz = GetPyjets()->P[2][n+i];
661 e = GetPyjets()->P[3][n+i];
664 void AliPythia6::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
666 // Call Pythia showering
668 pyshow(ip1, ip2, qmax);
671 void AliPythia6::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
673 pyrobo(imi, ima, the, phi, bex, bey, bez);
678 void AliPythia6::InitQuenching(Float_t cMin, Float_t cMax, Float_t k, Int_t iECMethod, Float_t zmax, Int_t ngmax)
681 // (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
682 // (2) The nuclear geometry using the Glauber Model
685 fGlauber = new AliFastGlauber();
687 fGlauber->SetCentralityClass(cMin, cMax);
689 fQuenchingWeights = new AliQuenchingWeights();
690 fQuenchingWeights->InitMult();
691 fQuenchingWeights->SetK(k);
692 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
699 void AliPythia6::Quench()
703 // Simple Jet Quenching routine:
704 // =============================
705 // The jet formed by all final state partons radiated by the parton created
706 // in the hard collisions is quenched by a factor (1-z) using light cone variables in
707 // the initial parton reference frame:
708 // (E + p_z)new = (1-z) (E + p_z)old
713 // The lost momentum is first balanced by one gluon with virtuality > 0.
714 // Subsequently the gluon splits to yield two gluons with E = p.
718 static Float_t eMean = 0.;
719 static Int_t icall = 0;
724 Int_t klast[4] = {-1, -1, -1, -1};
726 Int_t numpart = fPyjets->N;
727 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0., phi = 0.;
728 Double_t pxq[4], pyq[4], pzq[4], eq[4], yq[4], mq[4], pq[4], phiq[4], thetaq[4], ptq[4];
736 // Sore information about Primary partons
739 // 0, 1 partons from hard scattering
740 // 2, 3 partons from initial state radiation
742 for (Int_t i = 2; i <= 7; i++) {
744 // Skip gluons that participate in hard scattering
745 if (i == 4 || i == 5) continue;
746 // Gluons from hard Scattering
747 if (i == 6 || i == 7) {
749 pxq[j] = fPyjets->P[0][i];
750 pyq[j] = fPyjets->P[1][i];
751 pzq[j] = fPyjets->P[2][i];
752 eq[j] = fPyjets->P[3][i];
753 mq[j] = fPyjets->P[4][i];
755 // Gluons from initial state radiation
757 // Obtain 4-momentum vector from difference between original parton and parton after gluon
758 // radiation. Energy is calculated independently because initial state radition does not
759 // conserve strictly momentum and energy for each partonic system independently.
761 // Not very clean. Should be improved !
765 pxq[j] = fPyjets->P[0][i] - fPyjets->P[0][i+2];
766 pyq[j] = fPyjets->P[1][i] - fPyjets->P[1][i+2];
767 pzq[j] = fPyjets->P[2][i] - fPyjets->P[2][i+2];
768 mq[j] = fPyjets->P[4][i];
769 eq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j] + mq[j] * mq[j]);
772 // Calculate some kinematic variables
774 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
775 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
776 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
777 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
778 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
779 qPdg[j] = fPyjets->K[1][i];
785 fGlauber->GetI0I1ForPythiaAndXY(4, phiq, int0, int1, fXJet, fYJet, 15.);
787 for (Int_t j = 0; j < 4; j++) {
789 // Quench only central jets and with E > 10.
793 Int_t itype = (qPdg[j] == 21) ? 2 : 1;
794 Double_t eloss = fQuenchingWeights->GetELossRandomKFast(itype, int0[j], int1[j], eq[j]);
796 if (TMath::Abs(yq[j]) > 2.5 || eq[j] < 10.) {
799 if (eq[j] > 40. && TMath::Abs(yq[j]) < 0.5) {
805 Double_t l = fQuenchingWeights->CalcLk(int0[j], int1[j]);
806 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->CalcQk(int0[j], int1[j]));
808 // Fractional energy loss
809 fZQuench[j] = eloss / eq[j];
811 // Avoid complete loss
813 if (fZQuench[j] == 1.) fZQuench[j] = fZmax;
815 // Some debug printing
818 // 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",
819 // j, itype, eq[j], phiq[j], l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
821 // fZQuench[j] = 0.8;
822 // while (fZQuench[j] >= 0.95) fZQuench[j] = gRandom->Exp(0.2);
825 quenched[j] = (fZQuench[j] > 0.01);
830 Double_t pNew[1000][4];
837 for (Int_t isys = 0; isys < 4; isys++) {
838 // Skip to next system if not quenched.
839 if (!quenched[isys]) continue;
841 nGluon[isys] = 1 + Int_t(fZQuench[isys] / (1. - fZQuench[isys]));
842 if (nGluon[isys] > fNGmax) nGluon[isys] = fNGmax;
843 zquench[isys] = 1. - TMath::Power(1. - fZQuench[isys], 1./Double_t(nGluon[isys]));
844 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
850 Double_t pg[4] = {0., 0., 0., 0.};
853 // Loop on radiation events
855 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
858 for (Int_t k = 0; k < 4; k++)
865 for (Int_t i = 0; i < numpart; i++)
867 imo = fPyjets->K[2][i];
868 kst = fPyjets->K[0][i];
869 pdg = fPyjets->K[1][i];
873 // Quarks and gluons only
874 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
875 // Particles from hard scattering only
877 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
878 Int_t imom = imo % 1000;
879 if ((isys == 0 || isys == 1) && ((imom != (isys + 7)))) continue;
880 if ((isys == 2 || isys == 3) && ((imom != (isys + 1)))) continue;
883 // Skip comment lines
884 if (kst != 1 && kst != 2) continue;
887 px = fPyjets->P[0][i];
888 py = fPyjets->P[1][i];
889 pz = fPyjets->P[2][i];
890 e = fPyjets->P[3][i];
891 m = fPyjets->P[4][i];
892 pt = TMath::Sqrt(px * px + py * py);
893 p = TMath::Sqrt(px * px + py * py + pz * pz);
894 phi = TMath::Pi() + TMath::ATan2(-py, -px);
895 theta = TMath::ATan2(pt, pz);
898 // Save 4-momentum sum for balancing
909 // Fractional energy loss
910 Double_t z = zquench[index];
913 // Don't fully quench radiated gluons
916 // This small factor makes sure that the gluons are not too close in phase space to avoid recombination
921 // printf("z: %d %f\n", imo, z);
928 // Transform into frame in which initial parton is along z-axis
930 TVector3 v(px, py, pz);
931 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
932 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
934 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
935 Double_t mt2 = jt * jt + m * m;
938 // Kinematic limit on z
940 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
942 // Change light-cone kinematics rel. to initial parton
944 Double_t eppzOld = e + pl;
945 Double_t empzOld = e - pl;
947 Double_t eppzNew = (1. - z) * eppzOld;
948 Double_t empzNew = empzOld - mt2 * z / eppzOld;
949 Double_t eNew = 0.5 * (eppzNew + empzNew);
950 Double_t plNew = 0.5 * (eppzNew - empzNew);
954 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
955 Double_t mt2New = eppzNew * empzNew;
956 if (mt2New < 1.e-8) mt2New = 0.;
958 if (m * m > mt2New) {
960 // This should not happen
962 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
965 jtNew = TMath::Sqrt(mt2New - m * m);
968 // If pT is to small (probably a leading massive particle) we scale only the energy
969 // This can cause negative masses of the radiated gluon
970 // Let's hope for the best ...
972 eNew = TMath::Sqrt(plNew * plNew + mt2);
976 // Calculate new px, py
978 Double_t pxNew = jtNew / jt * pxs;
979 Double_t pyNew = jtNew / jt * pys;
981 // Double_t dpx = pxs - pxNew;
982 // Double_t dpy = pys - pyNew;
983 // Double_t dpz = pl - plNew;
984 // Double_t de = e - eNew;
985 // Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
986 // printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
987 // printf("New mass (2) %e %e \n", pxNew, pyNew);
991 TVector3 w(pxNew, pyNew, plNew);
992 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
993 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
995 p1[index][0] += pxNew;
996 p1[index][1] += pyNew;
997 p1[index][2] += plNew;
998 p1[index][3] += eNew;
1000 // Updated 4-momentum vectors
1002 pNew[icount][0] = pxNew;
1003 pNew[icount][1] = pyNew;
1004 pNew[icount][2] = plNew;
1005 pNew[icount][3] = eNew;
1010 // Check if there was phase-space for quenching
1013 if (icount == 0) quenched[isys] = kFALSE;
1014 if (!quenched[isys]) break;
1016 for (Int_t j = 0; j < 4; j++)
1018 p2[isys][j] = p0[isys][j] - p1[isys][j];
1020 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];
1021 if (p2[isys][4] > 0.) {
1022 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
1025 printf("Warning negative mass squared in system %d %f ! \n", isys, zquench[isys]);
1026 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]);
1027 if (p2[isys][4] < -0.01) {
1028 printf("Negative mass squared !\n");
1029 // Here we have to put the gluon back to mass shell
1030 // This will lead to a small energy imbalance
1032 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
1041 printf("zHeavy lowered to %f\n", zHeavy);
1042 if (zHeavy < 0.01) {
1043 printf("No success ! \n");
1045 quenched[isys] = kFALSE;
1049 } // iteration on z (while)
1051 // Update event record
1052 for (Int_t k = 0; k < icount; k++) {
1053 // 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] );
1054 fPyjets->P[0][kNew[k]] = pNew[k][0];
1055 fPyjets->P[1][kNew[k]] = pNew[k][1];
1056 fPyjets->P[2][kNew[k]] = pNew[k][2];
1057 fPyjets->P[3][kNew[k]] = pNew[k][3];
1064 if (!quenched[isys]) continue;
1066 // Last parton from shower i
1067 Int_t in = klast[isys];
1069 // Continue if no parton in shower i selected
1070 if (in == -1) continue;
1072 // If this is the second initial parton and it is behind the first move pointer by previous ish
1073 if (isys == 1 && klast[1] > klast[0]) in += ish;
1078 // How many additional gluons will be generated
1080 if (p2[isys][4] > 0.05) ish = 2;
1082 // Position of gluons
1084 if (iglu == 0) igMin = iGlu;
1087 (fPyjets->N) += ish;
1090 fPyjets->P[0][iGlu] = p2[isys][0];
1091 fPyjets->P[1][iGlu] = p2[isys][1];
1092 fPyjets->P[2][iGlu] = p2[isys][2];
1093 fPyjets->P[3][iGlu] = p2[isys][3];
1094 fPyjets->P[4][iGlu] = p2[isys][4];
1096 fPyjets->K[0][iGlu] = 1;
1097 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
1098 fPyjets->K[1][iGlu] = 21;
1099 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1100 fPyjets->K[3][iGlu] = -1;
1101 fPyjets->K[4][iGlu] = -1;
1103 pg[0] += p2[isys][0];
1104 pg[1] += p2[isys][1];
1105 pg[2] += p2[isys][2];
1106 pg[3] += p2[isys][3];
1109 // Split gluon in rest frame.
1111 Double_t bx = p2[isys][0] / p2[isys][3];
1112 Double_t by = p2[isys][1] / p2[isys][3];
1113 Double_t bz = p2[isys][2] / p2[isys][3];
1114 Double_t pst = p2[isys][4] / 2.;
1116 // Isotropic decay ????
1117 Double_t cost = 2. * gRandom->Rndm() - 1.;
1118 Double_t sint = TMath::Sqrt(1. - cost * cost);
1119 Double_t phis = 2. * TMath::Pi() * gRandom->Rndm();
1121 Double_t pz1 = pst * cost;
1122 Double_t pz2 = -pst * cost;
1123 Double_t pt1 = pst * sint;
1124 Double_t pt2 = -pst * sint;
1125 Double_t px1 = pt1 * TMath::Cos(phis);
1126 Double_t py1 = pt1 * TMath::Sin(phis);
1127 Double_t px2 = pt2 * TMath::Cos(phis);
1128 Double_t py2 = pt2 * TMath::Sin(phis);
1130 fPyjets->P[0][iGlu] = px1;
1131 fPyjets->P[1][iGlu] = py1;
1132 fPyjets->P[2][iGlu] = pz1;
1133 fPyjets->P[3][iGlu] = pst;
1134 fPyjets->P[4][iGlu] = 0.;
1136 fPyjets->K[0][iGlu] = 1 ;
1137 fPyjets->K[1][iGlu] = 21;
1138 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
1139 fPyjets->K[3][iGlu] = -1;
1140 fPyjets->K[4][iGlu] = -1;
1142 fPyjets->P[0][iGlu+1] = px2;
1143 fPyjets->P[1][iGlu+1] = py2;
1144 fPyjets->P[2][iGlu+1] = pz2;
1145 fPyjets->P[3][iGlu+1] = pst;
1146 fPyjets->P[4][iGlu+1] = 0.;
1148 fPyjets->K[0][iGlu+1] = 1;
1149 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
1150 fPyjets->K[1][iGlu+1] = 21;
1151 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
1152 fPyjets->K[3][iGlu+1] = -1;
1153 fPyjets->K[4][iGlu+1] = -1;
1159 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
1162 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
1163 Double_t px, py, pz;
1164 px = fPyjets->P[0][ig];
1165 py = fPyjets->P[1][ig];
1166 pz = fPyjets->P[2][ig];
1167 TVector3 v(px, py, pz);
1168 v.RotateZ(-phiq[isys]);
1169 v.RotateY(-thetaq[isys]);
1170 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1171 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1172 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1173 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1174 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1175 pxs += jtKick * TMath::Cos(phiKick);
1176 pys += jtKick * TMath::Sin(phiKick);
1177 TVector3 w(pxs, pys, pzs);
1178 w.RotateY(thetaq[isys]);
1179 w.RotateZ(phiq[isys]);
1180 fPyjets->P[0][ig] = w.X();
1181 fPyjets->P[1][ig] = w.Y();
1182 fPyjets->P[2][ig] = w.Z();
1183 fPyjets->P[2][ig] = w.Mag();
1189 // Check energy conservation
1193 Double_t es = 14000.;
1195 for (Int_t i = 0; i < numpart; i++)
1197 kst = fPyjets->K[0][i];
1198 if (kst != 1 && kst != 2) continue;
1199 pxs += fPyjets->P[0][i];
1200 pys += fPyjets->P[1][i];
1201 pzs += fPyjets->P[2][i];
1202 es -= fPyjets->P[3][i];
1204 if (TMath::Abs(pxs) > 1.e-2 ||
1205 TMath::Abs(pys) > 1.e-2 ||
1206 TMath::Abs(pzs) > 1.e-1) {
1207 printf("%e %e %e %e\n", pxs, pys, pzs, es);
1208 // Fatal("Quench()", "4-Momentum non-conservation");
1211 } // end quenching loop (systems)
1213 for (Int_t i = 0; i < numpart; i++)
1215 imo = fPyjets->K[2][i];
1217 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1224 void AliPythia6::Pyquen(Double_t a, Int_t ibf, Double_t b)
1226 // Igor Lokthine's quenching routine
1227 // http://lokhtin.web.cern.ch/lokhtin/pyquen/pyquen.txt
1232 void AliPythia6::SetPyquenParameters(Double_t t0, Double_t tau0, Int_t nf, Int_t iengl, Int_t iangl)
1234 // Set the parameters for the PYQUEN package.
1235 // See comments in PyquenCommon.h
1241 PYQPAR.iengl = iengl;
1242 PYQPAR.iangl = iangl;
1245 void AliPythia6::LoadEvent(AliStack* stack, Int_t flag, Int_t reHadr)
1248 // Load event into Pythia Common Block
1251 Int_t npart = stack -> GetNprimary();
1255 GetPyjets()->N = npart;
1257 n0 = GetPyjets()->N;
1258 GetPyjets()->N = n0 + npart;
1262 for (Int_t part = 0; part < npart; part++) {
1263 TParticle *mPart = stack->Particle(part);
1265 Int_t kf = mPart->GetPdgCode();
1266 Int_t ks = mPart->GetStatusCode();
1267 Int_t idf = mPart->GetFirstDaughter();
1268 Int_t idl = mPart->GetLastDaughter();
1271 if (ks == 11 || ks == 12) {
1278 Float_t px = mPart->Px();
1279 Float_t py = mPart->Py();
1280 Float_t pz = mPart->Pz();
1281 Float_t e = mPart->Energy();
1282 Float_t m = mPart->GetCalcMass();
1285 (GetPyjets())->P[0][part+n0] = px;
1286 (GetPyjets())->P[1][part+n0] = py;
1287 (GetPyjets())->P[2][part+n0] = pz;
1288 (GetPyjets())->P[3][part+n0] = e;
1289 (GetPyjets())->P[4][part+n0] = m;
1291 (GetPyjets())->K[1][part+n0] = kf;
1292 (GetPyjets())->K[0][part+n0] = ks;
1293 (GetPyjets())->K[3][part+n0] = idf + 1;
1294 (GetPyjets())->K[4][part+n0] = idl + 1;
1295 (GetPyjets())->K[2][part+n0] = mPart->GetFirstMother() + 1;
1300 void AliPythia6::Pyevnw()
1302 // New multiple interaction scenario
1306 void AliPythia6::GetQuenchingParameters(Double_t& xp, Double_t& yp, Double_t z[4])
1308 // Return event specific quenching parameters
1311 for (Int_t i = 0; i < 4; i++) z[i] = fZQuench[i];
1315 void AliPythia6::ConfigHeavyFlavor()
1318 // Default configuration for Heavy Flavor production
1320 // All QCD processes
1324 // No multiple interactions
1328 // Initial/final parton shower on (Pythia default)
1332 // 2nd order alpha_s
1340 void AliPythia6::AtlasTuning()
1343 // Configuration for the ATLAS tuning
1344 SetMSTP(51,AliStructFuncType::PDFsetIndex(kCTEQ5L));
1345 SetMSTP(81,1); // Multiple Interactions ON
1346 SetMSTP(82,4); // Double Gaussian Model
1347 SetPARP(81,1.9); // Min. pt for multiple interactions (default in 6.2-14)
1348 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
1349 SetPARP(89,1000.); // [GeV] Ref. energy
1350 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
1351 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
1352 SetPARP(84,0.5); // Core radius
1353 SetPARP(85,0.33); // Regulates gluon prod. mechanism
1354 SetPARP(86,0.66); // Regulates gluon prod. mechanism
1355 SetPARP(67,1); // Regulates Initial State Radiation
1358 void AliPythia6::SetPtHardRange(Float_t ptmin, Float_t ptmax)
1360 // Set the pt hard range
1365 void AliPythia6::SetYHardRange(Float_t ymin, Float_t ymax)
1367 // Set the y hard range
1373 void AliPythia6::SetFragmentation(Int_t flag)
1375 // Switch fragmentation on/off
1379 void AliPythia6::SetInitialAndFinalStateRadiation(Int_t flag1, Int_t flag2)
1381 // initial state radiation
1383 // final state radiation
1387 void AliPythia6::SetIntrinsicKt(Float_t kt)
1389 // Set the inreinsic kt
1393 SetPARP(93, 4. * kt);
1399 void AliPythia6::SwitchHFOff()
1401 // Switch off heavy flavor
1402 // Maximum number of quark flavours used in pdf
1404 // Maximum number of flavors that can be used in showers
1408 void AliPythia6::SetPycellParameters(Float_t etamax, Int_t neta, Int_t nphi,
1409 Float_t thresh, Float_t etseed, Float_t minet, Float_t r)
1411 // Set pycell parameters
1412 SetPARU(51, etamax);
1415 SetPARU(58, thresh);
1416 SetPARU(52, etseed);
1422 void AliPythia6::ModifiedSplitting()
1424 // Modified splitting probability as a model for quenching
1426 SetMSTJ(41, 1); // QCD radiation only
1427 SetMSTJ(42, 2); // angular ordering
1428 SetMSTJ(44, 2); // option to run alpha_s
1429 SetMSTJ(47, 0); // No correction back to hard scattering element
1430 SetMSTJ(50, 0); // No coherence in first branching
1431 SetPARJ(82, 1.); // Cut off for parton showers
1434 void AliPythia6::SwitchHadronisationOff()
1436 // Switch off hadronisarion
1440 void AliPythia6::SwitchHadronisationOn()
1442 // Switch on hadronisarion
1447 void AliPythia6::GetXandQ(Float_t& x1, Float_t& x2, Float_t& q)
1449 // Get x1, x2 and Q for this event
1456 Float_t AliPythia6::GetXSection()
1458 // Get the total cross-section
1459 return (GetPARI(1));
1462 Float_t AliPythia6::GetPtHard()
1464 // Get the pT hard for this event
1468 Int_t AliPythia6::ProcessCode()
1470 // Get the subprocess code
1474 void AliPythia6::PrintStatistics()
1476 // End of run statistics
1480 void AliPythia6::EventListing()
1482 // End of run statistics
1486 AliPythia6& AliPythia6::operator=(const AliPythia6& rhs)
1488 // Assignment operator
1493 void AliPythia6::Copy(TObject&) const
1498 Fatal("Copy","Not implemented!\n");