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8d2cd130 1/**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
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 **************************************************************************/
15
7cdba479 16/* $Id$ */
8d2cd130 17
18#include "AliPythia.h"
7cdba479 19#include "AliPythiaRndm.h"
0f482ae4 20#include "../FASTSIM/AliFastGlauber.h"
21#include "../FASTSIM/AliQuenchingWeights.h"
22#include "TVector3.h"
8d2cd130 23
24ClassImp(AliPythia)
25
26#ifndef WIN32
27# define pyclus pyclus_
28# define pycell pycell_
452af8c7 29# define pyshow pyshow_
30# define pyrobo pyrobo_
8d2cd130 31# define type_of_call
32#else
33# define pyclus PYCLUS
34# define pycell PYCELL
452af8c7 35# define pyrobo PYROBO
8d2cd130 36# define type_of_call _stdcall
37#endif
38
39extern "C" void type_of_call pyclus(Int_t & );
40extern "C" void type_of_call pycell(Int_t & );
452af8c7 41extern "C" void type_of_call pyshow(Int_t &, Int_t &, Double_t &);
42extern "C" void type_of_call pyrobo(Int_t &, Int_t &, Double_t &, Double_t &, Double_t &, Double_t &, Double_t &);
8d2cd130 43
44//_____________________________________________________________________________
45
46AliPythia* AliPythia::fgAliPythia=NULL;
47
48AliPythia::AliPythia()
49{
50// Default Constructor
51//
52// Set random number
7cdba479 53 if (!AliPythiaRndm::GetPythiaRandom())
54 AliPythiaRndm::SetPythiaRandom(GetRandom());
0f482ae4 55 fGlauber = 0;
56 fQuenchingWeights = 0;
8d2cd130 57}
58
59void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfunc)
60{
61// Initialise the process to generate
7cdba479 62 if (!AliPythiaRndm::GetPythiaRandom())
63 AliPythiaRndm::SetPythiaRandom(GetRandom());
8d2cd130 64
65 fProcess = process;
66 fEcms = energy;
67 fStrucFunc = strucfunc;
68// don't decay p0
69 SetMDCY(Pycomp(111),1,0);
70// select structure function
71 SetMSTP(52,2);
72 SetMSTP(51,strucfunc);
73//
74// Pythia initialisation for selected processes//
75//
76// Make MSEL clean
77//
78 for (Int_t i=1; i<= 200; i++) {
79 SetMSUB(i,0);
80 }
81// select charm production
82 switch (process)
83 {
84 case kPyCharm:
85 SetMSEL(4);
86//
87// heavy quark masses
88
89 SetPMAS(4,1,1.2);
90 SetMSTU(16,2);
91//
92// primordial pT
93 SetMSTP(91,1);
94 SetPARP(91,1.);
95 SetPARP(93,5.);
96//
97 break;
98 case kPyBeauty:
99 SetMSEL(5);
100 SetPMAS(5,1,4.75);
101 SetMSTU(16,2);
102 break;
103 case kPyJpsi:
104 SetMSEL(0);
105// gg->J/Psi g
106 SetMSUB(86,1);
107 break;
108 case kPyJpsiChi:
109 SetMSEL(0);
110// gg->J/Psi g
111 SetMSUB(86,1);
112// gg-> chi_0c g
113 SetMSUB(87,1);
114// gg-> chi_1c g
115 SetMSUB(88,1);
116// gg-> chi_2c g
117 SetMSUB(89,1);
118 break;
119 case kPyCharmUnforced:
120 SetMSEL(0);
121// gq->qg
122 SetMSUB(28,1);
123// gg->qq
124 SetMSUB(53,1);
125// gg->gg
126 SetMSUB(68,1);
127 break;
128 case kPyBeautyUnforced:
129 SetMSEL(0);
130// gq->qg
131 SetMSUB(28,1);
132// gg->qq
133 SetMSUB(53,1);
134// gg->gg
135 SetMSUB(68,1);
136 break;
137 case kPyMb:
138// Minimum Bias pp-Collisions
139//
140//
141// select Pythia min. bias model
142 SetMSEL(0);
511db649 143 SetMSUB(92,1); // single diffraction AB-->XB
144 SetMSUB(93,1); // single diffraction AB-->AX
145 SetMSUB(94,1); // double diffraction
146 SetMSUB(95,1); // low pt production
147
148//
149// ATLAS Tuning
150//
0f482ae4 151 SetMSTP(51,7); // CTEQ5L pdf
511db649 152 SetMSTP(81,1); // Multiple Interactions ON
153 SetMSTP(82,4); // Double Gaussian Model
154
155 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
156 SetPARP(89,1000.); // [GeV] Ref. energy
157 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
158 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
159 SetPARP(84,0.5); // Core radius
160 SetPARP(85,0.33); // Regulates gluon prod. mechanism
161 SetPARP(86,0.66); // Regulates gluon prod. mechanism
162 SetPARP(67,1); // Regulates Initial State Radiation
163 break;
8d2cd130 164 case kPyMbNonDiffr:
165// Minimum Bias pp-Collisions
166//
167//
168// select Pythia min. bias model
169 SetMSEL(0);
511db649 170 SetMSUB(95,1); // low pt production
0f482ae4 171
172//
173// ATLAS Tuning
174//
511db649 175
0f482ae4 176 SetMSTP(51,7); // CTEQ5L pdf
511db649 177 SetMSTP(81,1); // Multiple Interactions ON
178 SetMSTP(82,4); // Double Gaussian Model
179
180 SetPARP(82,1.8); // [GeV] PT_min at Ref. energy
181 SetPARP(89,1000.); // [GeV] Ref. energy
182 SetPARP(90,0.16); // 2*epsilon (exponent in power law)
183 SetPARP(83,0.5); // Core density in proton matter distribution (def.value)
184 SetPARP(84,0.5); // Core radius
185 SetPARP(85,0.33); // Regulates gluon prod. mechanism
186 SetPARP(86,0.66); // Regulates gluon prod. mechanism
187 SetPARP(67,1); // Regulates Initial State Radiation
8d2cd130 188 break;
189 case kPyJets:
190//
191// QCD Jets
192//
193 SetMSEL(1);
194 break;
195 case kPyDirectGamma:
196 SetMSEL(10);
197 break;
adf4d898 198 case kPyCharmPbPbMNR:
199 case kPyD0PbPbMNR:
8d2cd130 200 // Tuning of Pythia parameters aimed to get a resonable agreement
201 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
202 // c-cbar single inclusive and double differential distributions.
203 // This parameter settings are meant to work with Pb-Pb collisions
adf4d898 204 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
8d2cd130 205 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
206 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
207
208 // All QCD processes
209 SetMSEL(1);
210
211 // No multiple interactions
212 SetMSTP(81,0);
213 SetPARP(81,0.0);
214 SetPARP(82,0.0);
215
216 // Initial/final parton shower on (Pythia default)
217 SetMSTP(61,1);
218 SetMSTP(71,1);
219
220 // 2nd order alpha_s
221 SetMSTP(2,2);
222
223 // QCD scales
224 SetMSTP(32,2);
225 SetPARP(34,1.0);
226
adf4d898 227 // Intrinsic <kT>
8d2cd130 228 SetMSTP(91,1);
229 SetPARP(91,1.304);
230 SetPARP(93,6.52);
231
232 // Set c-quark mass
233 SetPMAS(4,1,1.2);
234
235 break;
adf4d898 236 case kPyCharmpPbMNR:
237 case kPyD0pPbMNR:
238 // Tuning of Pythia parameters aimed to get a resonable agreement
239 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
240 // c-cbar single inclusive and double differential distributions.
241 // This parameter settings are meant to work with p-Pb collisions
242 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
243 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
244 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
245
246 // All QCD processes
247 SetMSEL(1);
248
249 // No multiple interactions
250 SetMSTP(81,0);
251 SetPARP(81,0.0);
252 SetPARP(82,0.0);
253
254 // Initial/final parton shower on (Pythia default)
255 SetMSTP(61,1);
256 SetMSTP(71,1);
257
258 // 2nd order alpha_s
259 SetMSTP(2,2);
260
261 // QCD scales
262 SetMSTP(32,2);
263 SetPARP(34,1.0);
264
265 // Intrinsic <kT>
266 SetMSTP(91,1);
267 SetPARP(91,1.16);
268 SetPARP(93,5.8);
269
270 // Set c-quark mass
271 SetPMAS(4,1,1.2);
272
273 break;
274 case kPyCharmppMNR:
275 case kPyD0ppMNR:
276 // Tuning of Pythia parameters aimed to get a resonable agreement
277 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
278 // c-cbar single inclusive and double differential distributions.
279 // This parameter settings are meant to work with pp collisions
280 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
281 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
282 // has to be set to 2.1GeV. Example in ConfigCharmPPR.C.
283
284 // All QCD processes
285 SetMSEL(1);
286
287 // No multiple interactions
288 SetMSTP(81,0);
289 SetPARP(81,0.0);
290 SetPARP(82,0.0);
291
292 // Initial/final parton shower on (Pythia default)
293 SetMSTP(61,1);
294 SetMSTP(71,1);
295
296 // 2nd order alpha_s
297 SetMSTP(2,2);
298
299 // QCD scales
300 SetMSTP(32,2);
301 SetPARP(34,1.0);
302
303 // Intrinsic <kT^2>
304 SetMSTP(91,1);
305 SetPARP(91,1.);
306 SetPARP(93,5.);
307
308 // Set c-quark mass
309 SetPMAS(4,1,1.2);
310
311 break;
312 case kPyBeautyPbPbMNR:
8d2cd130 313 // Tuning of Pythia parameters aimed to get a resonable agreement
314 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
315 // b-bbar single inclusive and double differential distributions.
316 // This parameter settings are meant to work with Pb-Pb collisions
317 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
318 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
319 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
320
321 // All QCD processes
322 SetMSEL(1);
323
324 // No multiple interactions
325 SetMSTP(81,0);
326 SetPARP(81,0.0);
327 SetPARP(82,0.0);
328
329 // Initial/final parton shower on (Pythia default)
330 SetMSTP(61,1);
331 SetMSTP(71,1);
332
333 // 2nd order alpha_s
334 SetMSTP(2,2);
335
336 // QCD scales
337 SetMSTP(32,2);
338 SetPARP(34,1.0);
339 SetPARP(67,1.0);
340 SetPARP(71,1.0);
341
adf4d898 342 // Intrinsic <kT>
8d2cd130 343 SetMSTP(91,1);
344 SetPARP(91,2.035);
345 SetPARP(93,10.17);
346
347 // Set b-quark mass
348 SetPMAS(5,1,4.75);
349
adf4d898 350 break;
351 case kPyBeautypPbMNR:
352 // Tuning of Pythia parameters aimed to get a resonable agreement
353 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
354 // b-bbar single inclusive and double differential distributions.
355 // This parameter settings are meant to work with p-Pb collisions
356 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
357 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
358 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
359
360 // All QCD processes
361 SetMSEL(1);
362
363 // No multiple interactions
364 SetMSTP(81,0);
365 SetPARP(81,0.0);
366 SetPARP(82,0.0);
367
368 // Initial/final parton shower on (Pythia default)
369 SetMSTP(61,1);
370 SetMSTP(71,1);
371
372 // 2nd order alpha_s
373 SetMSTP(2,2);
374
375 // QCD scales
376 SetMSTP(32,2);
377 SetPARP(34,1.0);
378 SetPARP(67,1.0);
379 SetPARP(71,1.0);
380
381 // Intrinsic <kT>
382 SetMSTP(91,1);
383 SetPARP(91,1.60);
384 SetPARP(93,8.00);
385
386 // Set b-quark mass
387 SetPMAS(5,1,4.75);
388
389 break;
390 case kPyBeautyppMNR:
391 // Tuning of Pythia parameters aimed to get a resonable agreement
392 // between with the NLO calculation by Mangano, Nason, Ridolfi for the
393 // b-bbar single inclusive and double differential distributions.
394 // This parameter settings are meant to work with pp collisions
395 // (AliGenPythia::SetNuclei) and with kCTEQ4L PDFs.
396 // To get a good agreement the minimum ptHard (AliGenPythia::SetPtHard)
397 // has to be set to 2.75GeV. Example in ConfigBeautyPPR.C.
398
399 // All QCD processes
400 SetMSEL(1);
401
402 // No multiple interactions
403 SetMSTP(81,0);
404 SetPARP(81,0.0);
405 SetPARP(82,0.0);
406
407 // Initial/final parton shower on (Pythia default)
408 SetMSTP(61,1);
409 SetMSTP(71,1);
410
411 // 2nd order alpha_s
412 SetMSTP(2,2);
413
414 // QCD scales
415 SetMSTP(32,2);
416 SetPARP(34,1.0);
417 SetPARP(67,1.0);
418 SetPARP(71,1.0);
419
420 // Intrinsic <kT>
421 SetMSTP(91,1);
422 SetPARP(91,1.);
423 SetPARP(93,5.);
424
425 // Set b-quark mass
426 SetPMAS(5,1,4.75);
427
8d2cd130 428 break;
429 }
430//
431// Initialize PYTHIA
432 SetMSTP(41,1); // all resonance decays switched on
433
434 Initialize("CMS","p","p",fEcms);
435
436}
437
438Int_t AliPythia::CheckedLuComp(Int_t kf)
439{
440// Check Lund particle code (for debugging)
441 Int_t kc=Pycomp(kf);
442 printf("\n Lucomp kf,kc %d %d",kf,kc);
443 return kc;
444}
445
446void AliPythia::SetNuclei(Int_t a1, Int_t a2)
447{
448// Treat protons as inside nuclei with mass numbers a1 and a2
449// The MSTP array in the PYPARS common block is used to enable and
450// select the nuclear structure functions.
451// MSTP(52) : (D=1) choice of proton and nuclear structure-function library
452// =1: internal PYTHIA acording to MSTP(51)
453// =2: PDFLIB proton s.f., with MSTP(51) = 1000xNGROUP+NSET
454// If the following mass number both not equal zero, nuclear corrections of the stf are used.
455// MSTP(192) : Mass number of nucleus side 1
456// MSTP(193) : Mass number of nucleus side 2
457 SetMSTP(52,2);
458 SetMSTP(192, a1);
459 SetMSTP(193, a2);
460}
461
462
463AliPythia* AliPythia::Instance()
464{
465// Set random number generator
466 if (fgAliPythia) {
467 return fgAliPythia;
468 } else {
469 fgAliPythia = new AliPythia();
470 return fgAliPythia;
471 }
472}
473
474void AliPythia::PrintParticles()
475{
476// Print list of particl properties
477 Int_t np = 0;
c31f1d37 478 char* name = new char[16];
8d2cd130 479 for (Int_t kf=0; kf<1000000; kf++) {
480 for (Int_t c = 1; c > -2; c-=2) {
8d2cd130 481 Int_t kc = Pycomp(c*kf);
482 if (kc) {
483 Float_t mass = GetPMAS(kc,1);
484 Float_t width = GetPMAS(kc,2);
485 Float_t tau = GetPMAS(kc,4);
c31f1d37 486
8d2cd130 487 Pyname(kf,name);
488
489 np++;
490
491 printf("\n mass, width, tau: %6d %s %10.3f %10.3e %10.3e",
492 c*kf, name, mass, width, tau);
493 }
494 }
495 }
496 printf("\n Number of particles %d \n \n", np);
497}
498
499void AliPythia::ResetDecayTable()
500{
501// Set default values for pythia decay switches
502 Int_t i;
503 for (i = 1; i < 501; i++) SetMDCY(i,1,fDefMDCY[i]);
504 for (i = 1; i < 2001; i++) SetMDME(i,1,fDefMDME[i]);
505}
506
507void AliPythia::SetDecayTable()
508{
509// Set default values for pythia decay switches
510//
511 Int_t i;
512 for (i = 1; i < 501; i++) fDefMDCY[i] = GetMDCY(i,1);
513 for (i = 1; i < 2001; i++) fDefMDME[i] = GetMDME(i,1);
514}
515
516void AliPythia::Pyclus(Int_t& njet)
517{
518// Call Pythia clustering algorithm
519//
520 pyclus(njet);
521}
522
523void AliPythia::Pycell(Int_t& njet)
524{
525// Call Pythia jet reconstruction algorithm
526//
527 pycell(njet);
528}
529
452af8c7 530void AliPythia::Pyshow(Int_t ip1, Int_t ip2, Double_t qmax)
531{
532// Call Pythia jet reconstruction algorithm
533//
452af8c7 534 pyshow(ip1, ip2, qmax);
535}
536
537void AliPythia::Pyrobo(Int_t imi, Int_t ima, Double_t the, Double_t phi, Double_t bex, Double_t bey, Double_t bez)
538{
539 pyrobo(imi, ima, the, phi, bex, bey, bez);
540}
541
542
543
0f482ae4 544void AliPythia::InitQuenching(Float_t cMin, Float_t cMax, Float_t qTransport, Float_t maxLength, Int_t iECMethod)
545{
546// Initializes
547// (1) The quenching model using quenching weights according to C. Salgado and U. Wiedemann
548// (2) The nuclear geometry using the Glauber Model
549//
550
551
552 fGlauber = new AliFastGlauber();
553 fGlauber->Init(2);
554 fGlauber->SetCentralityClass(cMin, cMax);
555
556 fQuenchingWeights = new AliQuenchingWeights();
557 fQuenchingWeights->InitMult();
558 fQuenchingWeights->SetQTransport(qTransport);
559 fQuenchingWeights->SetECMethod(AliQuenchingWeights::kECMethod(iECMethod));
560 fQuenchingWeights->SetLengthMax(Int_t(maxLength));
561 fQuenchingWeights->SampleEnergyLoss();
562
563}
564
565
452af8c7 566void AliPythia::Quench()
567{
568//
569//
570// Simple Jet Quenching routine:
571// =============================
572// The jet formed by all final state partons radiated by the parton created
0f482ae4 573// in the hard collisions is quenched by a factor (1-z) using light cone variables in
574// the initial parton reference frame:
452af8c7 575// (E + p_z)new = (1-z) (E + p_z)old
576//
0f482ae4 577//
578//
579//
452af8c7 580// The lost momentum is first balanced by one gluon with virtuality > 0.
581// Subsequently the gluon splits to yield two gluons with E = p.
582//
0f482ae4 583//
584//
4e383037 585 static Float_t eMean = 0.;
586 static Int_t icall = 0;
0f482ae4 587
588 Double_t p0[2][5];
589 Double_t p1[2][5];
590 Double_t p2[2][5];
452af8c7 591 Int_t klast[2] = {-1, -1};
592 Int_t kglu[2];
452af8c7 593
594 Int_t numpart = fPyjets->N;
0f482ae4 595 Double_t px = 0., py = 0., pz = 0., e = 0., m = 0., p = 0., pt = 0., theta = 0.;
596 Double_t pxq[2], pyq[2], pzq[2], eq[2], yq[2], mq[2], pq[2], phiq[2], thetaq[2], ptq[2];
597 Bool_t quenched[2];
598 Double_t phi;
599 Double_t zInitial[2], wjtKick[2];
4e383037 600 Int_t nGluon[2];
601
0f482ae4 602 Int_t imo, kst, pdg;
511db649 603//
0f482ae4 604// Primary partons
511db649 605//
4e383037 606
607
0f482ae4 608
609 for (Int_t i = 6; i <= 7; i++) {
610 Int_t j = i - 6;
452af8c7 611
0f482ae4 612 pxq[j] = fPyjets->P[0][i];
613 pyq[j] = fPyjets->P[1][i];
614 pzq[j] = fPyjets->P[2][i];
615 eq[j] = fPyjets->P[3][i];
616 mq[j] = fPyjets->P[4][i];
4e383037 617 yq[j] = 0.5 * TMath::Log((eq[j] + pzq[j] + 1.e-14) / (eq[j] - pzq[j] + 1.e-14));
0f482ae4 618 pq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j] + pzq[j] * pzq[j]);
619 phiq[j] = TMath::Pi()+TMath::ATan2(-pyq[j], -pxq[j]);
620 ptq[j] = TMath::Sqrt(pxq[j] * pxq[j] + pyq[j] * pyq[j]);
621 thetaq[j] = TMath::ATan2(ptq[j], pzq[j]);
622 phi = phiq[j];
623
624 // Quench only central jets
625 if (TMath::Abs(yq[j]) > 2.5) {
626 zInitial[j] = 0.;
627 } else {
628 pdg = fPyjets->K[1][i];
629
630 // Get length in nucleus
631 Double_t l;
632 fGlauber->GetLengthsForPythia(1, &phi, &l, -1.);
633 //
634 // Energy loss for given length and parton typr
635 Int_t itype = (pdg == 21) ? 2 : 1;
4e383037 636
0f482ae4 637 Double_t eloss = fQuenchingWeights->GetELossRandom(itype, l, eq[j]);
4e383037 638 if (eq[j] > 80. && TMath::Abs(yq[j]) < 0.5) {
639 icall ++;
640 eMean += eloss;
641 }
642
0f482ae4 643 //
644 // Extra pt
4e383037 645
0f482ae4 646 wjtKick[j] = TMath::Sqrt(l * fQuenchingWeights->GetQTransport());
647 //
648 // Fractional energy loss
649 zInitial[j] = eloss / eq[j];
650 //
651 // Avoid complete loss
652 //
653 if (zInitial[j] == 1.) zInitial[j] = 0.95;
654 //
655 // Some debug printing
4e383037 656 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",
657 j, itype, eq[j], phi, l, eloss, wjtKick[j], eMean / Float_t(icall+1), yq[j]);
658
659 zInitial[j] = 1.;
660 while (zInitial[j] >= 0.95) zInitial[j] = gRandom->Exp(0.2);
0f482ae4 661 }
4e383037 662
0f482ae4 663 quenched[j] = (zInitial[j] > 0.01);
4e383037 664 } // primary partons
0f482ae4 665
6e90ad26 666 Double_t pNew[1000][4];
667 Int_t kNew[1000];
668 Int_t icount = 0;
669//
4e383037 670// System Loop
671 for (Int_t isys = 0; isys < 2; isys++) {
6e90ad26 672// Skip to next system if not quenched.
4e383037 673 if (!quenched[isys]) continue;
674
675 nGluon[isys] = 1 + Int_t(zInitial[isys] / (1. - zInitial[isys]));
676 if (nGluon[isys] > 6) nGluon[isys] = 6;
677 zInitial[isys] = 1. - TMath::Power(1. - zInitial[isys], 1./Double_t(nGluon[isys]));
678 wjtKick[isys] = wjtKick[isys] / TMath::Sqrt(Double_t(nGluon[isys]));
0f482ae4 679
4e383037 680
681
682 Int_t igMin = -1;
683 Int_t igMax = -1;
684 Double_t pg[4] = {0., 0., 0., 0.};
685
686//
687// Loop on radiation events
688
689 for (Int_t iglu = 0; iglu < nGluon[isys]; iglu++) {
6e90ad26 690 Double_t zHeavy = zInitial[isys];
6e90ad26 691//
4e383037 692
6e90ad26 693 while (1) {
694 icount = 0;
695 for (Int_t k = 0; k < 4; k++)
696 {
697 p0[isys][k] = 0.;
698 p1[isys][k] = 0.;
699 p2[isys][k] = 0.;
700 }
701// Loop over partons
702 for (Int_t i = 0; i < numpart; i++)
703 {
704 imo = fPyjets->K[2][i];
705 kst = fPyjets->K[0][i];
706 pdg = fPyjets->K[1][i];
707
708
709
0f482ae4 710// Quarks and gluons only
6e90ad26 711 if (pdg != 21 && TMath::Abs(pdg) > 6) continue;
0f482ae4 712// Particles from hard scattering only
6e90ad26 713 if (imo > 8 && imo < 1000) imo = fPyjets->K[2][imo - 1];
4e383037 714 if (imo != (isys + 7) && (imo % 1000) != (isys + 7)) continue;
6e90ad26 715
0f482ae4 716// Skip comment lines
6e90ad26 717 if (kst != 1 && kst != 2) continue;
0f482ae4 718//
719// Parton kinematic
6e90ad26 720 px = fPyjets->P[0][i];
721 py = fPyjets->P[1][i];
722 pz = fPyjets->P[2][i];
723 e = fPyjets->P[3][i];
724 m = fPyjets->P[4][i];
725 pt = TMath::Sqrt(px * px + py * py);
726 p = TMath::Sqrt(px * px + py * py + pz * pz);
727 phi = TMath::Pi() + TMath::ATan2(-py, -px);
728 theta = TMath::ATan2(pt, pz);
729
0f482ae4 730//
731// Save 4-momentum sum for balancing
6e90ad26 732 Int_t index = imo - 7;
4e383037 733 if (index >= 1000) index = imo % 1000 - 7;
6e90ad26 734
735 p0[index][0] += px;
736 p0[index][1] += py;
737 p0[index][2] += pz;
738 p0[index][3] += e;
6e90ad26 739
740 klast[index] = i;
741
0f482ae4 742//
743// Fractional energy loss
6e90ad26 744 Double_t z = zInitial[index];
4e383037 745
746// Don't fully quench radiated gluons
747//
748 if (imo > 1000) {
749// This small factor makes sure that the gluons are not too close in phase space to avoid recombination
750//
751
752 z = 0.05;
753 }
754
755//
756
6e90ad26 757 if (m > 0.) z = zHeavy;
758
759 //
760 //
761 // Transform into frame in which initial parton is along z-axis
762 //
763 TVector3 v(px, py, pz);
764 v.RotateZ(-phiq[index]); v.RotateY(-thetaq[index]);
765 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pl = v.Z();
766
767 Double_t jt = TMath::Sqrt(pxs * pxs + pys * pys);
768 Double_t mt2 = jt * jt + m * m;
769 Double_t zmax = 1.;
770 //
771 // Kinematic limit on z
772 //
4e383037 773 if (m > 0.) zmax = 1. - m / TMath::Sqrt(m * m + jt * jt);
6e90ad26 774 //
775 // Change light-cone kinematics rel. to initial parton
776 //
777 Double_t eppzOld = e + pl;
778 Double_t empzOld = e - pl;
779
780 Double_t eppzNew = (1. - z) * eppzOld;
781 Double_t empzNew = empzOld - mt2 * z / eppzOld;
782 Double_t eNew = 0.5 * (eppzNew + empzNew);
783 Double_t plNew = 0.5 * (eppzNew - empzNew);
784
785 Double_t jtNew;
786 //
787 // if mt very small (or sometimes even < 0 for numerical reasons) set it to 0
788 Double_t mt2New = eppzNew * empzNew;
789 if (mt2New < 1.e-8) mt2New = 0.;
4e383037 790 if (z < zmax) {
791 if (m * m > mt2New) {
792 //
793 // This should not happen
794 //
795 Fatal("Quench()", "This should never happen %e %e %e!", m, eppzNew, empzNew);
796 jtNew = 0;
797 } else {
798 jtNew = TMath::Sqrt(mt2New - m * m);
799 }
6e90ad26 800 } else {
4e383037 801 // If pT is to small (probably a leading massive particle) we scale only the energy
802 // This can cause negative masses of the radiated gluon
803 // Let's hope for the best ...
804 jtNew = jt;
805 eNew = TMath::Sqrt(plNew * plNew + mt2);
806
6e90ad26 807 }
6e90ad26 808 //
809 // Calculate new px, py
810 //
811 Double_t pxNew = jtNew / jt * pxs;
812 Double_t pyNew = jtNew / jt * pys;
813
814// Double_t dpx = pxs - pxNew;
815// Double_t dpy = pys - pyNew;
816// Double_t dpz = pl - plNew;
817// Double_t de = e - eNew;
818// Double_t dmass2 = de * de - dpx * dpx - dpy * dpy - dpz * dpz;
819// printf("New mass (1) %e %e %e %e %e %e %e \n", dmass2, jt, jtNew, pl, plNew, e, eNew);
820// printf("New mass (2) %e %e \n", pxNew, pyNew);
821 //
822 // Rotate back
823 //
824 TVector3 w(pxNew, pyNew, plNew);
825 w.RotateY(thetaq[index]); w.RotateZ(phiq[index]);
826 pxNew = w.X(); pyNew = w.Y(); plNew = w.Z();
827
828 p1[index][0] += pxNew;
829 p1[index][1] += pyNew;
830 p1[index][2] += plNew;
831 p1[index][3] += eNew;
832 //
833 // Updated 4-momentum vectors
834 //
835 pNew[icount][0] = pxNew;
836 pNew[icount][1] = pyNew;
837 pNew[icount][2] = plNew;
838 pNew[icount][3] = eNew;
839 kNew[icount] = i;
840 icount++;
841 } // parton loop
0f482ae4 842 //
6e90ad26 843 // Check if there was phase-space for quenching
0f482ae4 844 //
0f482ae4 845
6e90ad26 846 if (icount == 0) quenched[isys] = kFALSE;
847 if (!quenched[isys]) break;
848
849 for (Int_t j = 0; j < 4; j++)
850 {
851 p2[isys][j] = p0[isys][j] - p1[isys][j];
852 }
853 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];
6e90ad26 854 if (p2[isys][4] > 0.) {
855 p2[isys][4] = TMath::Sqrt(p2[isys][4]);
856 break;
857 } else {
858 printf("Warning negative mass squared in system %d %f ! \n", isys, zInitial[isys]);
4e383037 859 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]);
6e90ad26 860 if (p2[isys][4] < -0.01) {
4e383037 861 printf("Negative mass squared !\n");
862 // Here we have to put the gluon back to mass shell
863 // This will lead to a small energy imbalance
864 p2[isys][4] = 0.;
865 p2[isys][3] = TMath::Sqrt(p2[isys][0] * p2[isys][0] + p2[isys][1] * p2[isys][1] + p2[isys][2] * p2[isys][2]);
866 break;
6e90ad26 867 } else {
868 p2[isys][4] = 0.;
869 break;
870 }
871 }
6e90ad26 872 /*
6e90ad26 873 zHeavy *= 0.98;
874 printf("zHeavy lowered to %f\n", zHeavy);
875 if (zHeavy < 0.01) {
876 printf("No success ! \n");
877 icount = 0;
878 quenched[isys] = kFALSE;
879 break;
880 }
4e383037 881 */
882 } // iteration on z (while)
883
6e90ad26 884// Update event record
885 for (Int_t k = 0; k < icount; k++) {
886// 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] );
887 fPyjets->P[0][kNew[k]] = pNew[k][0];
888 fPyjets->P[1][kNew[k]] = pNew[k][1];
889 fPyjets->P[2][kNew[k]] = pNew[k][2];
890 fPyjets->P[3][kNew[k]] = pNew[k][3];
0f482ae4 891 }
4e383037 892 //
893 // Add the gluons
894 //
895 Int_t ish = 0;
896 Int_t iGlu, jmin, jmax, iNew;
897 if (!quenched[isys]) continue;
0f482ae4 898//
899// Last parton from shower i
4e383037 900 Int_t in = klast[isys];
0f482ae4 901//
902// Continue if no parton in shower i selected
903 if (in == -1) continue;
904//
905// If this is the second initial parton and it is behind the first move pointer by previous ish
4e383037 906 if (isys == 1 && klast[1] > klast[0]) in += ish;
0f482ae4 907//
908// Starting index
452af8c7 909
4e383037 910// jmin = in - 1;
0f482ae4 911// How many additional gluons will be generated
912 ish = 1;
4e383037 913 if (p2[isys][4] > 0.05) ish = 2;
0f482ae4 914//
915// Position of gluons
4e383037 916 iGlu = numpart;
917 if (iglu == 0) igMin = iGlu;
918 igMax = iGlu;
0f482ae4 919 numpart += ish;
920 (fPyjets->N) += ish;
4e383037 921
0f482ae4 922 if (ish == 1) {
4e383037 923 fPyjets->P[0][iGlu] = p2[isys][0];
924 fPyjets->P[1][iGlu] = p2[isys][1];
925 fPyjets->P[2][iGlu] = p2[isys][2];
926 fPyjets->P[3][iGlu] = p2[isys][3];
927 fPyjets->P[4][iGlu] = p2[isys][4];
0f482ae4 928
4e383037 929 fPyjets->K[0][iGlu] = 1;
930 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu] = 1;
0f482ae4 931 fPyjets->K[1][iGlu] = 21;
4e383037 932 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
0f482ae4 933 fPyjets->K[3][iGlu] = -1;
934 fPyjets->K[4][iGlu] = -1;
4e383037 935
936 pg[0] += p2[isys][0];
937 pg[1] += p2[isys][1];
938 pg[2] += p2[isys][2];
939 pg[3] += p2[isys][3];
0f482ae4 940 } else {
941 //
942 // Split gluon in rest frame.
943 //
4e383037 944 Double_t bx = p2[isys][0] / p2[isys][3];
945 Double_t by = p2[isys][1] / p2[isys][3];
946 Double_t bz = p2[isys][2] / p2[isys][3];
947 Double_t pst = p2[isys][4] / 2.;
0f482ae4 948 //
949 // Isotropic decay ????
950 Double_t cost = 2. * gRandom->Rndm() - 1.;
951 Double_t sint = TMath::Sqrt(1. - cost * cost);
952 Double_t phi = 2. * TMath::Pi() * gRandom->Rndm();
953
954 Double_t pz1 = pst * cost;
955 Double_t pz2 = -pst * cost;
956 Double_t pt1 = pst * sint;
957 Double_t pt2 = -pst * sint;
958 Double_t px1 = pt1 * TMath::Cos(phi);
959 Double_t py1 = pt1 * TMath::Sin(phi);
960 Double_t px2 = pt2 * TMath::Cos(phi);
961 Double_t py2 = pt2 * TMath::Sin(phi);
962
963 fPyjets->P[0][iGlu] = px1;
964 fPyjets->P[1][iGlu] = py1;
965 fPyjets->P[2][iGlu] = pz1;
966 fPyjets->P[3][iGlu] = pst;
967 fPyjets->P[4][iGlu] = 0.;
968
4e383037 969 fPyjets->K[0][iGlu] = 1 ;
0f482ae4 970 fPyjets->K[1][iGlu] = 21;
4e383037 971 fPyjets->K[2][iGlu] = fPyjets->K[2][in] + 1000;
0f482ae4 972 fPyjets->K[3][iGlu] = -1;
973 fPyjets->K[4][iGlu] = -1;
974
975 fPyjets->P[0][iGlu+1] = px2;
976 fPyjets->P[1][iGlu+1] = py2;
977 fPyjets->P[2][iGlu+1] = pz2;
978 fPyjets->P[3][iGlu+1] = pst;
979 fPyjets->P[4][iGlu+1] = 0.;
980
4e383037 981 fPyjets->K[0][iGlu+1] = 1;
982 if (iglu == nGluon[isys] - 1) fPyjets->K[0][iGlu+1] = 1;
0f482ae4 983 fPyjets->K[1][iGlu+1] = 21;
4e383037 984 fPyjets->K[2][iGlu+1] = fPyjets->K[2][in] + 1000;
0f482ae4 985 fPyjets->K[3][iGlu+1] = -1;
986 fPyjets->K[4][iGlu+1] = -1;
987 SetMSTU(1,0);
988 SetMSTU(2,0);
989 //
990 // Boost back
991 //
992 Pyrobo(iGlu + 1, iGlu + 2, 0., 0., bx, by, bz);
993 }
4e383037 994/*
995 for (Int_t ig = iGlu; ig < iGlu+ish; ig++) {
996 Double_t px, py, pz;
997 px = fPyjets->P[0][ig];
998 py = fPyjets->P[1][ig];
999 pz = fPyjets->P[2][ig];
1000 TVector3 v(px, py, pz);
1001 v.RotateZ(-phiq[isys]);
1002 v.RotateY(-thetaq[isys]);
1003 Double_t pxs = v.X(); Double_t pys = v.Y(); Double_t pzs = v.Z();
1004 Double_t r = AliPythiaRndm::GetPythiaRandom()->Rndm();
1005 Double_t jtKick = 0.3 * TMath::Sqrt(-TMath::Log(r));
1006 if (ish == 2) jtKick = wjtKick[i] * TMath::Sqrt(-TMath::Log(r)) / TMath::Sqrt(2.);
1007 Double_t phiKick = 2. * TMath::Pi() * AliPythiaRndm::GetPythiaRandom()->Rndm();
1008 pxs += jtKick * TMath::Cos(phiKick);
1009 pys += jtKick * TMath::Sin(phiKick);
1010 TVector3 w(pxs, pys, pzs);
1011 w.RotateY(thetaq[isys]);
1012 w.RotateZ(phiq[isys]);
1013 fPyjets->P[0][ig] = w.X();
1014 fPyjets->P[1][ig] = w.Y();
1015 fPyjets->P[2][ig] = w.Z();
1016 fPyjets->P[2][ig] = w.Mag();
1017 }
1018*/
1019 } // kGluon
1020
6e90ad26 1021
4e383037 1022 // Check energy conservation
0f482ae4 1023 Double_t pxs = 0.;
1024 Double_t pys = 0.;
1025 Double_t pzs = 0.;
1026 Double_t es = 14000.;
1027
1028 for (Int_t i = 0; i < numpart; i++)
1029 {
1030 kst = fPyjets->K[0][i];
1031 if (kst != 1 && kst != 2) continue;
1032 pxs += fPyjets->P[0][i];
1033 pys += fPyjets->P[1][i];
1034 pzs += fPyjets->P[2][i];
1035 es -= fPyjets->P[3][i];
1036 }
1037 if (TMath::Abs(pxs) > 1.e-2 ||
1038 TMath::Abs(pys) > 1.e-2 ||
1039 TMath::Abs(pzs) > 1.e-1) {
1040 printf("%e %e %e %e\n", pxs, pys, pzs, es);
4e383037 1041// Fatal("Quench()", "4-Momentum non-conservation");
452af8c7 1042 }
4e383037 1043
1044 } // end quenching loop (systems)
6e90ad26 1045// Clean-up
0f482ae4 1046 for (Int_t i = 0; i < numpart; i++)
1047 {
4e383037 1048 imo = fPyjets->K[2][i];
1049 if (imo > 1000) {
1050 fPyjets->K[2][i] = fPyjets->K[2][i] % 1000;
1051 }
0f482ae4 1052 }
4e383037 1053// this->Pylist(1);
0f482ae4 1054} // end quench