updated parametrisation for pi0, eta, omega, phi for different energies, allow select...
[u/mrichter/AliRoot.git] / EVGEN / AliDecayerExodus.cxx
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b5c4afc6 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
16
17#include "AliDecayerExodus.h"
18#include <Riostream.h>
19#include <TMath.h>
20#include <AliLog.h>
21#include <TH1.h>
22#include <TRandom.h>
23#include <TParticle.h>
24#include <TDatabasePDG.h>
25#include <TPDGCode.h>
26#include <TLorentzVector.h>
27#include <TClonesArray.h>
28
29
30ClassImp(AliDecayerExodus)
31
76e6e4c5 32//---------------------------------------------------------------------------------------------------
33//
34// Generate electron-pair mass distributions for Dalitz decays according
35// to the Kroll-Wada parametrization: N. Kroll, W. Wada: Phys. Rev 98(1955)1355
36// and generate electron-pair mass distributions for resonances according
37// to the Gounaris-Sakurai parametrization: G.J. Gounaris, J.J. Sakurai: Phys.Rev.Lett. 21(1968)244
38//
39// For the electromagnetic form factor the parameterization from
40// Lepton-G is used: L.G. Landsberg et al.: Phys. Rep. 128(1985)301
41//
42// Ralf Averbeck (R.Averbeck@gsi.de)
43// Irem Erdemir (irem.erdemir@cern.ch)
44//
45//---------------------------------------------------------------------------------------------------
46
47
b5c4afc6 48AliDecayerExodus::AliDecayerExodus():
49 AliDecayer(),
50 fEPMassPion(0),
51 fEPMassEta(0),
52 fEPMassEtaPrime(0),
53 fEPMassRho(0),
54 fEPMassOmega(0),
55 fEPMassOmegaDalitz(0),
56 fEPMassPhi(0),
57 fEPMassPhiDalitz(0),
58 fEPMassJPsi(0),
59 fInit(0)
60
61{
62// Constructor
63}
64
65
66void AliDecayerExodus::Init()
67{
68
69// Initialisation
70//
71 Int_t ibin, nbins;
72 Double_t min, maxpion, maxeta, maxomega, maxetaprime, maxphi, binwidth_pion, binwidth_eta, binwidth_omega, binwidth_etaprime, binwidth_phi;
73 Double_t pionmass, etamass, omegamass, etaprimemass, phimass, emass, omasspion, omasseta, omassgamma;
74 Double_t epsilon_pion, epsilon_eta, epsilon_omega, epsilon_etaprime, epsilon_phi;
75 Double_t delta_pion, delta_eta, delta_omega, delta_etaprime, delta_phi;
76 Double_t mLL_pion, mLL_eta, mLL_omega, mLL_etaprime, mLL_phi;
77 Double_t q_pion, q_eta, q_omega, q_etaprime, q_phi;
78 Double_t kwHelp_pion, kwHelp_eta, kwHelp_omega, kwHelp_etaprime, kwHelp_phi;
79 Double_t krollWada_pion, krollWada_eta, krollWada_omega, krollWada_etaprime, krollWada_phi;
80 Double_t formFactor_pion, formFactor_eta, formFactor_omega, formFactor_etaprime, formFactor_phi;
81 Double_t weight_pion, weight_eta, weight_omega_dalitz, weight_etaprime, weight_phi_dalitz;
82
83 Float_t binwidth;
84 Float_t mass_bin, mass_min, mass_max;
85 Double_t vmass_rho, vmass_omega, vmass_phi, vmass_jpsi, vwidth_rho, vwidth_omega, vwidth_phi, vwidth_jpsi;
86 Double_t weight_rho, weight_omega, weight_phi, weight_jpsi;
87
88//================================================================================//
89// Create electron pair mass histograms from dalitz decays //
90//================================================================================//
91
92 // Get the particle masses
93 // parent
94 nbins = 1000;
95
96 pionmass = (TDatabasePDG::Instance()->GetParticle(111))->Mass();
97 etamass = (TDatabasePDG::Instance()->GetParticle(221))->Mass();
98 omegamass = (TDatabasePDG::Instance()->GetParticle(223))->Mass();
99 etaprimemass = (TDatabasePDG::Instance()->GetParticle(331))->Mass();
100 phimass = (TDatabasePDG::Instance()->GetParticle(333))->Mass();
101 // child - electron
102 emass = (TDatabasePDG::Instance()->GetParticle(11))->Mass();
103 // child - other : third childs from Dalitz decays
104 omasspion = pionmass;
105 omasseta = etamass;
106 omassgamma = 0.;
107
108 min = 2.0 * emass;
109 maxpion = pionmass - omassgamma;
110 maxeta = etamass - omassgamma;
111 maxomega = omegamass - pionmass;
112 maxetaprime = etaprimemass - omassgamma;
113 maxphi = phimass - omasseta;
114
115 binwidth_pion = (maxpion - min) / (Double_t)nbins;
116 binwidth_eta = (maxeta - min) / (Double_t)nbins;
117 binwidth_omega = (maxomega - min) / (Double_t)nbins;
118 binwidth_etaprime = (maxetaprime - min) / (Double_t)nbins;
119 binwidth_phi = (maxphi - min) / (Double_t)nbins;
120
121
122 epsilon_pion = (emass / pionmass) * (emass / pionmass);
123 epsilon_eta = (emass / etamass) * (emass / etamass);
124 epsilon_omega = (emass / omegamass) * (emass / omegamass);
125 epsilon_etaprime = (emass / etaprimemass) * (emass / etaprimemass);
126 epsilon_phi = (emass / phimass) * (emass / phimass);
127
128
129 delta_pion = (omassgamma / pionmass) * (omassgamma / pionmass);
130 delta_eta = (omassgamma / etamass) * (omassgamma / etamass);
131 delta_omega = (omasspion / omegamass) * (omasspion / omegamass);
132 delta_etaprime = (omassgamma / etaprimemass) * (omassgamma / etaprimemass);
133 delta_phi = (omasseta / phimass) * (omasseta / phimass);
134
135
136
137 // create pair mass histograms for Dalitz decays of pi0, eta, omega, eta' and phi
138 if (!fEPMassPion) {delete fEPMassPion; fEPMassPion = new TH1F("fEPMassPion", "Dalitz electron pair from pion", nbins, min, maxpion); }
139 if (!fEPMassEta) {delete fEPMassEta; fEPMassEta = new TH1F("fEPMassEta", "Dalitz electron pair from eta", nbins, min, maxeta);}
140 if (!fEPMassOmegaDalitz) {delete fEPMassOmegaDalitz; fEPMassOmegaDalitz = new TH1F("fEPMassOmegaDalitz", "Dalitz electron pair from omega ", nbins, min, maxomega);}
141 if (!fEPMassEtaPrime) {delete fEPMassEtaPrime; fEPMassEtaPrime = new TH1F("fEPMassEtaPrime", "Dalitz electron pair from etaprime", nbins, min, maxetaprime);}
142 if (!fEPMassPhiDalitz) {delete fEPMassPhiDalitz; fEPMassPhiDalitz = new TH1F("fEPMassPhiDalitz", "Dalitz electron pair from phi ", nbins, min, maxphi);}
143
144
145 mLL_pion = mLL_eta = mLL_omega = mLL_etaprime = mLL_phi = 0.;
146
147 for (ibin = 1; ibin <= nbins; ibin++ )
148 {
149 mLL_pion = min + (Double_t)(ibin - 1) * binwidth_pion + binwidth_pion / 2.0;
150 mLL_eta = min + (Double_t)(ibin - 1) * binwidth_eta + binwidth_eta / 2.0;
151 mLL_omega = min + (Double_t)(ibin - 1) * binwidth_omega + binwidth_omega / 2.0;
152 mLL_etaprime = min + (Double_t)(ibin - 1) * binwidth_etaprime + binwidth_etaprime / 2.0;
153 mLL_phi = min + (Double_t)(ibin - 1) * binwidth_phi + binwidth_phi / 2.0;
154
155
156 q_pion = (mLL_pion / pionmass) * (mLL_pion / pionmass);
157 q_eta = (mLL_eta / etamass) * (mLL_eta / etamass);
158 q_omega = (mLL_omega / omegamass)*(mLL_omega / omegamass);
159 q_etaprime = (mLL_etaprime / etaprimemass) * (mLL_etaprime / etaprimemass);
160 q_phi = (mLL_phi / phimass) * (mLL_phi / phimass);
161
162 if ( q_pion <= 4.0 * epsilon_pion || q_eta <= 4.0 * epsilon_eta || q_omega <= 4.0 * epsilon_omega || q_etaprime <= 4.0 * epsilon_etaprime || q_phi <= 4.0 * epsilon_phi )
163 {
164 AliFatal("Error in calculating Dalitz mass histogram binning!");
165 }
166
167
168 kwHelp_pion = (1.0 + q_pion / (1.0 - delta_pion)) * (1.0 + q_pion / (1.0 - delta_pion))
169 - 4.0 * q_pion / ((1.0 - delta_pion) * (1.0 - delta_pion));
170
171 kwHelp_eta = (1.0 + q_eta / (1.0 - delta_eta)) * (1.0 + q_eta / (1.0 - delta_eta))
172 - 4.0 * q_eta / ((1.0 - delta_eta) * (1.0 - delta_eta));
173
174 kwHelp_omega = (1.0 + q_omega / (1.0 - delta_omega)) * (1.0 + q_omega / (1.0 - delta_omega))
175 - 4.0 * q_omega / ((1.0 - delta_omega) * (1.0 - delta_omega));
176
177 kwHelp_etaprime = (1.0 + q_etaprime / (1.0 - delta_etaprime)) * (1.0 + q_etaprime / (1.0 - delta_etaprime))
178 - 4.0 * q_etaprime / ((1.0 - delta_etaprime) * (1.0 - delta_etaprime));
179
180 kwHelp_phi = (1.0 + q_phi / (1.0 - delta_phi)) * (1.0 + q_phi / (1.0 - delta_phi))
181 - 4.0 * q_phi / ((1.0 - delta_phi) * (1.0 - delta_phi));
182
183
184
185
186 if ( kwHelp_pion <= 0.0 || kwHelp_eta <= 0.0 || kwHelp_omega <= 0.0 || kwHelp_etaprime <= 0.0 || kwHelp_phi <= 0.0 )
187 {
188 AliFatal("Error in calculating Dalitz mass histogram binning!");
189
190 }
191
192
193 // Invariant mass distributions of electron pairs from Dalitz decays
194 // using Kroll-Wada function
195
196 krollWada_pion = (2.0 / mLL_pion) * TMath::Exp(1.5 * TMath::Log(kwHelp_pion))
197 * TMath::Sqrt(1.0 - 4.0 * epsilon_pion / q_pion)
198 * (1.0 + 2.0 * epsilon_pion / q_pion);
199
200
201 krollWada_eta = (2.0 / mLL_eta) * TMath::Exp(1.5 * TMath::Log(kwHelp_eta))
202 * TMath::Sqrt(1.0 - 4.0 * epsilon_eta / q_eta)
203 * (1.0 + 2.0 * epsilon_eta / q_eta);
204
205
206 krollWada_omega = (2.0 / mLL_omega) * TMath::Exp(1.5 * TMath::Log(kwHelp_omega))
207 * TMath::Sqrt(1.0 - 4.0 * epsilon_omega / q_omega)
208 * (1.0 + 2.0 * epsilon_omega / q_omega);
209
210
211 krollWada_etaprime = (2.0 / mLL_etaprime) * TMath::Exp(1.5 * TMath::Log(kwHelp_etaprime))
212 * TMath::Sqrt(1.0 - 4.0 * epsilon_etaprime / q_etaprime)
213 * (1.0 + 2.0 * epsilon_etaprime / q_etaprime);
214
215 krollWada_phi = (2.0 / mLL_phi) * TMath::Exp(1.5 * TMath::Log(kwHelp_phi))
216 * TMath::Sqrt(1.0 - 4.0 * epsilon_phi / q_phi)
217 * (1.0 + 2.0 * epsilon_phi / q_phi);
218
219
220
221 // Form factors from Lepton-G
222 formFactor_pion = 1.0/(1.0-5.5*mLL_pion*mLL_pion);
223 formFactor_eta = 1.0/(1.0-1.9*mLL_eta*mLL_eta);
224 formFactor_omega = (TMath::Power(TMath::Power(0.6519,2),2))
225 /(TMath::Power(TMath::Power(0.6519,2)-TMath::Power(mLL_omega, 2), 2)
226 + TMath::Power(0.04198, 2)*TMath::Power(0.6519, 2));
227 formFactor_etaprime = (TMath::Power(TMath::Power(0.764,2),2))
228 /(TMath::Power(TMath::Power(0.764,2)-TMath::Power(mLL_etaprime, 2), 2)
229 + TMath::Power(0.1020, 2)*TMath::Power(0.764, 2));
230 formFactor_phi = 1.0;
231
232
233
234
235 weight_pion = krollWada_pion * formFactor_pion * formFactor_pion;
236 weight_eta = krollWada_eta * formFactor_eta * formFactor_eta;
237 weight_omega_dalitz = krollWada_omega * formFactor_omega;
238 weight_etaprime = krollWada_etaprime * formFactor_etaprime;
239 weight_phi_dalitz = krollWada_phi * formFactor_phi * formFactor_phi;
240
241
242 // Fill histograms of electron pair masses from dalitz decays
243 fEPMassPion ->AddBinContent(ibin, weight_pion);
244 fEPMassEta ->AddBinContent(ibin, weight_eta);
245 fEPMassOmegaDalitz->AddBinContent(ibin, weight_omega_dalitz);
246 fEPMassEtaPrime ->AddBinContent(ibin, weight_etaprime);
247 fEPMassPhiDalitz ->AddBinContent(ibin, weight_phi_dalitz);
248 }
249
250
251
252
253//===================================================================================//
254// Create electron pair mass histograms from resonance decays //
255//===================================================================================//
256
257 Double_t pimass = 0.13956995;
258
259 // Get the particle masses
260 // parent
261 vmass_rho = (TDatabasePDG::Instance()->GetParticle(113))->Mass();
262 vmass_omega = (TDatabasePDG::Instance()->GetParticle(223))->Mass();
263 vmass_phi = (TDatabasePDG::Instance()->GetParticle(333))->Mass();
264 vmass_jpsi = (TDatabasePDG::Instance()->GetParticle(443))->Mass();
265 // Get the particle widths
266 // parent
267 vwidth_rho = (TDatabasePDG::Instance()->GetParticle(113))->Width();
268 vwidth_omega = (TDatabasePDG::Instance()->GetParticle(223))->Width();
269 vwidth_phi = (TDatabasePDG::Instance()->GetParticle(333))->Width();
270 vwidth_jpsi = (TDatabasePDG::Instance()->GetParticle(443))->Width();
271
272
273 if ( mass_min == 0. && mass_max == 0. )
274 {
275 mass_min = 2.*pimass;
276 mass_max = 5.;
277 }
278
279 binwidth = (mass_max-mass_min)/(Double_t)nbins;
280
281 // create pair mass histograms for resonances of rho, omega, phi and jpsi
282 if (!fEPMassRho) {delete fEPMassRho; fEPMassRho = new TH1F("fEPMassRho","mass rho",nbins,mass_min,mass_max);}
283 if (!fEPMassOmega) {delete fEPMassOmega; fEPMassOmega = new TH1F("fEPMassOmega","mass omega",nbins,mass_min,mass_max);}
284 if (!fEPMassPhi) {delete fEPMassPhi; fEPMassPhi = new TH1F("fEPMassPhi","mass phi",nbins,mass_min,mass_max);}
285 if (!fEPMassJPsi) {delete fEPMassJPsi; fEPMassJPsi = new TH1F("fEPMassJPsi","mass jpsi",nbins,mass_min,mass_max);}
286
287
288 for (ibin=1; ibin<=nbins; ibin++ )
289 {
290 mass_bin = mass_min+(Double_t)(ibin-1)*binwidth+binwidth/2.0;
291
292 weight_rho = (Float_t)GounarisSakurai(mass_bin,vmass_rho,vwidth_rho,emass);
293 weight_omega = (Float_t)GounarisSakurai(mass_bin,vmass_omega,vwidth_omega,emass);
294 weight_phi = (Float_t)GounarisSakurai(mass_bin,vmass_phi,vwidth_phi,emass);
76e6e4c5 295 weight_jpsi = (Float_t)Lorentz(mass_bin,vmass_jpsi,vwidth_jpsi);
b5c4afc6 296
297 // Fill histograms of electron pair masses from resonance decays
298 fEPMassRho ->AddBinContent(ibin,weight_rho);
299 fEPMassOmega->AddBinContent(ibin,weight_omega);
300 fEPMassPhi ->AddBinContent(ibin,weight_phi);
301 fEPMassJPsi ->AddBinContent(ibin,weight_jpsi);
302 }
303
304}
305
306Double_t AliDecayerExodus::GounarisSakurai(Float_t mass, Double_t vmass, Double_t vwidth, Double_t emass)
307{
308// Invariant mass distributions of electron pairs from resonance decays
76e6e4c5 309// of rho, omega and phi
b5c4afc6 310// using Gounaris-Sakurai function
311
312 Double_t corr = 0.;
313 Double_t epsilon = 0.;
314 Double_t weight = 0.;
315
316 Double_t pimass = 0.13956995;
76e6e4c5 317
5abb8148 318 if(mass>pimass){
76e6e4c5 319 corr = vwidth*(vmass/mass)*exp(1.5*log((mass*mass/4.0-pimass*pimass)
320 /(vmass*vmass/4.0-pimass*pimass)));
5abb8148 321 }
b5c4afc6 322
b5c4afc6 323 epsilon = (emass/mass)*(emass/mass);
324
325 if ( 1.0-4.0*epsilon>=0.0 )
326 {
327 weight = sqrt(1.0-4.0*epsilon)*(1.0+2.0*epsilon)/
328 ((vmass*vmass-mass*mass)*(vmass*vmass-mass*mass)+
329 (vmass*corr)*(vmass*corr));
330 }
331 return weight;
332}
333
334
76e6e4c5 335Double_t AliDecayerExodus::Lorentz(Float_t mass, Double_t vmass, Double_t vwidth)
336{
337// Invariant mass distributions of electron pairs from resonance decay
338// of jpsi (and it can also be used for other particles except rho, omega and phi)
339// using Lorentz function
340
341 Double_t weight;
342
343 weight = (vwidth*vwidth/4.0)/(vwidth*vwidth/4.0+(vmass-mass)*(vmass-mass));
344
345 return weight;
346
347}
348
b5c4afc6 349void AliDecayerExodus::Decay(Int_t idpart, TLorentzVector* pparent)
350{
351
352 if (!fInit) {
353 Init();
354 fInit=1;
355 }
356
357
358 Double_t pmass_pion, pmass_eta, pmass_omega_dalitz, pmass_etaprime, pmass_phi_dalitz;
359 Double_t emass, omass_pion, omass_eta, omass_gamma, epmass_pion, epmass_eta, epmass_omega_dalitz, epmass_etaprime, epmass_phi_dalitz;
360 Double_t e1_pion, e1_eta, e1_omega, e1_etaprime, e1_phi;
361 Double_t p1_pion, p1_eta, p1_omega, p1_etaprime, p1_phi;
362 Double_t e3_gamma_pion, e3_gamma_eta, e3_pion, e3_gamma_etaprime, e3_eta;
363 Double_t p3_gamma_pion, p3_gamma_eta, p3_pion, p3_gamma_etaprime, p3_eta;
364
365 Double_t wp_rho, wp_omega, wp_phi, wp_jpsi, epmass_rho, epmass_omega, epmass_phi, epmass_jpsi;
366 Double_t mp_rho, mp_omega, mp_phi, mp_jpsi, md_rho, md_omega, md_phi, md_jpsi;
367 Double_t Ed_rho, Ed_omega, Ed_phi, Ed_jpsi, pd_rho, pd_omega, pd_phi, pd_jpsi;
368
369
370 md_rho = md_omega = md_phi = md_jpsi = 0.;
371
372
373 Double_t costheta, sintheta, cosphi, sinphi, phi;
374
375 // Get the particle masses of daughters
376 emass = (TDatabasePDG::Instance()->GetParticle(11)) ->Mass();
377 omass_pion = (TDatabasePDG::Instance()->GetParticle(111))->Mass();
378 omass_eta = (TDatabasePDG::Instance()->GetParticle(221))->Mass();
379 omass_gamma = (TDatabasePDG::Instance()->GetParticle(22)) ->Mass();
380
381 // Get the particle widths of mothers for resonances
382 wp_rho = (TDatabasePDG::Instance()->GetParticle(113))->Width();
383 wp_omega = (TDatabasePDG::Instance()->GetParticle(223))->Width();
384 wp_phi = (TDatabasePDG::Instance()->GetParticle(333))->Width();
385 wp_jpsi = (TDatabasePDG::Instance()->GetParticle(443))->Width();
386
387 costheta = (2.0 * gRandom->Rndm()) - 1.;
388 sintheta = TMath::Sqrt((1. + costheta) * (1. - costheta));
389 phi = 2.0 * TMath::ACos(-1.) * gRandom->Rndm();
390 sinphi = TMath::Sin(phi);
391 cosphi = TMath::Cos(phi);
392
393
394//-----------------------------------------------------------------------------//
395// Generate Pizero Dalitz decay //
396//-----------------------------------------------------------------------------//
397
398 if(idpart==111){
399 pmass_pion = pparent->M();
400
401 for(;;){
402 // Sample the electron pair mass from a histogram
403 epmass_pion = fEPMassPion->GetRandom();
404 if (pmass_pion-omass_gamma>epmass_pion && epmass_pion/2.>emass) break;
405 }
406
407 // electron pair kinematics in virtual photon rest frame
408 e1_pion = epmass_pion / 2.;
409 p1_pion = TMath::Sqrt((e1_pion + emass) * (e1_pion - emass));
410
411 // momentum vectors of electrons in virtual photon rest frame
412 Double_t pProd1_pion[3] = {p1_pion * sintheta * cosphi,
413 p1_pion * sintheta * sinphi,
414 p1_pion * costheta};
415
416 Double_t pProd2_pion[3] = {-1.0 * p1_pion * sintheta * cosphi,
417 -1.0 * p1_pion * sintheta * sinphi,
418 -1.0 * p1_pion * costheta};
419
420
421 // third child kinematics in parent meson rest frame
422 e3_gamma_pion = (pmass_pion * pmass_pion - epmass_pion * epmass_pion)/(2. * pmass_pion);
423 p3_gamma_pion = TMath::Sqrt((e3_gamma_pion * e3_gamma_pion));
424
425
426 // third child 4-vector in parent meson rest frame
427 fProducts_pion[2].SetPx(p3_gamma_pion * sintheta * cosphi);
428 fProducts_pion[2].SetPy(p3_gamma_pion * sintheta * sinphi);
429 fProducts_pion[2].SetPz(p3_gamma_pion * costheta);
430 fProducts_pion[2].SetE(e3_gamma_pion);
431
432
433 // electron 4-vectors in properly rotated virtual photon rest frame
434 Double_t pRot1_pion[3] = {0.};
435 Rot(pProd1_pion, pRot1_pion, costheta, -sintheta, -cosphi, -sinphi);
436 Double_t pRot2_pion[3] = {0.};
437 Rot(pProd2_pion, pRot2_pion, costheta, -sintheta, -cosphi, -sinphi);
438 fProducts_pion[0].SetPx(pRot1_pion[0]);
439 fProducts_pion[0].SetPy(pRot1_pion[1]);
440 fProducts_pion[0].SetPz(pRot1_pion[2]);
441 fProducts_pion[0].SetE(e1_pion);
442 fProducts_pion[1].SetPx(pRot2_pion[0]);
443 fProducts_pion[1].SetPy(pRot2_pion[1]);
444 fProducts_pion[1].SetPz(pRot2_pion[2]);
445 fProducts_pion[1].SetE(e1_pion);
446
447 // boost the dielectron into the parent meson's rest frame
448 Double_t eLPparent_pion = TMath::Sqrt(p3_gamma_pion * p3_gamma_pion + epmass_pion * epmass_pion);
449 TVector3 boostPair_pion( -1.0 * fProducts_pion[2].Px() / eLPparent_pion,
450 -1.0 * fProducts_pion[2].Py() / eLPparent_pion,
451 -1.0 * fProducts_pion[2].Pz() / eLPparent_pion);
452 fProducts_pion[0].Boost(boostPair_pion);
453 fProducts_pion[1].Boost(boostPair_pion);
454
455 // boost all decay products into the lab frame
456 TVector3 boostLab_pion(pparent->Px() / pparent->E(),
457 pparent->Py() / pparent->E(),
458 pparent->Pz() / pparent->E());
459
460 fProducts_pion[0].Boost(boostLab_pion);
461 fProducts_pion[1].Boost(boostLab_pion);
462 fProducts_pion[2].Boost(boostLab_pion);
463
464 }
465
466
467//-----------------------------------------------------------------------------//
468// Generate Rho resonance decay //
469//-----------------------------------------------------------------------------//
470
471 else if(idpart==113){
472 // calculate rho mass
473 if(wp_rho!=0.0){
474 mp_rho = pparent->M();
475 }
476 else{
477 Double_t x_rho=pparent->Px(); Double_t y_rho=pparent->Py(); Double_t z_rho=pparent->Pz();
478 Double_t t_rho=pparent->E();
479 Double_t p_rho=x_rho*x_rho+y_rho*y_rho+z_rho*z_rho;
480 Double_t Q2_rho=abs((t_rho*t_rho)-(p_rho*p_rho));
481 mp_rho = sqrt(Q2_rho);
482 }
483 // daughter
484 if ( mp_rho < 2.*md_rho )
485 {
486 printf("Rho into ee Decay kinematically impossible! \n");
487 return;
488 }
489
490 for( ;; ) {
491 // Sample the electron pair mass from a histogram
492 epmass_rho = fEPMassRho->GetRandom();
493 if ( mp_rho < 2.*epmass_rho ) break;
494 }
495
496 // electron pair kinematics in virtual photon rest frame
497 Ed_rho = epmass_rho/2.;
498 pd_rho = TMath::Sqrt((Ed_rho+md_rho)*(Ed_rho-md_rho));
499
500 // momentum vectors of electrons in virtual photon rest frame
501 Double_t pProd1_rho[3] = {pd_rho * sintheta * cosphi,
502 pd_rho * sintheta * sinphi,
503 pd_rho * costheta};
504
505 Double_t pProd2_rho[3] = {-1.0 * pd_rho * sintheta * cosphi,
506 -1.0 * pd_rho * sintheta * sinphi,
507 -1.0 * pd_rho * costheta};
508
509
510 // electron 4 vectors in properly rotated virtual photon rest frame
511 Double_t pRot1_rho[3] = {0.};
512 Rot(pProd1_rho, pRot1_rho, costheta, -sintheta, -cosphi, -sinphi);
513 Double_t pRot2_rho[3] = {0.};
514 Rot(pProd2_rho, pRot2_rho, costheta, -sintheta, -cosphi, -sinphi);
515 fProducts_rho[0].SetPx(pRot1_rho[0]);
516 fProducts_rho[0].SetPy(pRot1_rho[1]);
517 fProducts_rho[0].SetPz(pRot1_rho[2]);
518 fProducts_rho[0].SetE(Ed_rho);
519 fProducts_rho[1].SetPx(pRot2_rho[0]);
520 fProducts_rho[1].SetPy(pRot2_rho[1]);
521 fProducts_rho[1].SetPz(pRot2_rho[2]);
522 fProducts_rho[1].SetE(Ed_rho);
523
524
525 // boost decay products into the lab frame
526 TVector3 boostLab_rho(pparent->Px() / pparent->E(),
527 pparent->Py() / pparent->E(),
528 pparent->Pz() / pparent->E());
529
530 fProducts_rho[0].Boost(boostLab_rho);
531 fProducts_rho[1].Boost(boostLab_rho);
532 }
533
534
535//-----------------------------------------------------------------------------//
536// Generate Eta Dalitz decay //
537//-----------------------------------------------------------------------------//
538
539 else if(idpart==221){
540 pmass_eta = pparent->M();
541
542 for(;;){
543 // Sample the electron pair mass from a histogram
544 epmass_eta = fEPMassEta->GetRandom();
545 if(pmass_eta-omass_gamma>epmass_eta && epmass_eta/2.>emass)
546 break;
547 }
548
549 // electron pair kinematics in virtual photon rest frame
550 e1_eta = epmass_eta / 2.;
551 p1_eta = TMath::Sqrt((e1_eta + emass) * (e1_eta - emass));
552
553 // momentum vectors of electrons in virtual photon rest frame
554 Double_t pProd1_eta[3] = {p1_eta * sintheta * cosphi,
555 p1_eta * sintheta * sinphi,
556 p1_eta * costheta};
557 Double_t pProd2_eta[3] = {-1.0 * p1_eta * sintheta * cosphi,
558 -1.0 * p1_eta * sintheta * sinphi,
559 -1.0 * p1_eta * costheta};
560
561 // third child kinematics in parent meson rest frame
562 e3_gamma_eta = (pmass_eta * pmass_eta - epmass_eta * epmass_eta)/(2. * pmass_eta);
563 p3_gamma_eta = TMath::Sqrt((e3_gamma_eta * e3_gamma_eta));
564
565
566 // third child 4-vector in parent meson rest frame
567 fProducts_eta[2].SetPx(p3_gamma_eta * sintheta * cosphi);
568 fProducts_eta[2].SetPy(p3_gamma_eta * sintheta * sinphi);
569 fProducts_eta[2].SetPz(p3_gamma_eta * costheta);
570 fProducts_eta[2].SetE(e3_gamma_eta);
571
572 // electron 4-vectors in properly rotated virtual photon rest frame
573 Double_t pRot1_eta[3] = {0.};
574 Rot(pProd1_eta, pRot1_eta, costheta, -sintheta, -cosphi, -sinphi);
575 Double_t pRot2_eta[3] = {0.};
576 Rot(pProd2_eta, pRot2_eta, costheta, -sintheta, -cosphi, -sinphi);
577 fProducts_eta[0].SetPx(pRot1_eta[0]);
578 fProducts_eta[0].SetPy(pRot1_eta[1]);
579 fProducts_eta[0].SetPz(pRot1_eta[2]);
580 fProducts_eta[0].SetE(e1_eta);
581 fProducts_eta[1].SetPx(pRot2_eta[0]);
582 fProducts_eta[1].SetPy(pRot2_eta[1]);
583 fProducts_eta[1].SetPz(pRot2_eta[2]);
584 fProducts_eta[1].SetE(e1_eta);
585
586 // boost the dielectron into the parent meson's rest frame
587 Double_t eLPparent_eta = TMath::Sqrt(p3_gamma_eta * p3_gamma_eta + epmass_eta * epmass_eta);
588 TVector3 boostPair_eta( -1.0 * fProducts_eta[2].Px() / eLPparent_eta,
589 -1.0 * fProducts_eta[2].Py() / eLPparent_eta,
590 -1.0 * fProducts_eta[2].Pz() / eLPparent_eta);
591 fProducts_eta[0].Boost(boostPair_eta);
592 fProducts_eta[1].Boost(boostPair_eta);
593
594 // boost all decay products into the lab frame
595 TVector3 boostLab_eta(pparent->Px() / pparent->E(),
596 pparent->Py() / pparent->E(),
597 pparent->Pz() / pparent->E());
598
599 fProducts_eta[0].Boost(boostLab_eta);
600 fProducts_eta[1].Boost(boostLab_eta);
601 fProducts_eta[2].Boost(boostLab_eta);
602
603 }
604
605
606//-----------------------------------------------------------------------------//
607// Generate Omega Dalitz decay //
608//-----------------------------------------------------------------------------//
609
610 else if(idpart==223){
611 pmass_omega_dalitz = pparent->M();
612 for(;;){
613 // Sample the electron pair mass from a histogram
614 epmass_omega_dalitz = fEPMassOmegaDalitz->GetRandom();
615 if(pmass_omega_dalitz-omass_pion>epmass_omega_dalitz && epmass_omega_dalitz/2.>emass)
616 break;}
617
618 // electron pair kinematics in virtual photon rest frame
619 e1_omega = epmass_omega_dalitz / 2.;
620 p1_omega = TMath::Sqrt((e1_omega + emass) * (e1_omega - emass));
621
622 // momentum vectors of electrons in virtual photon rest frame
623 Double_t pProd1_omega_dalitz[3] = {p1_omega * sintheta * cosphi,
624 p1_omega * sintheta * sinphi,
625 p1_omega * costheta};
626 Double_t pProd2_omega_dalitz[3] = {-1.0 * p1_omega * sintheta * cosphi,
627 -1.0 * p1_omega * sintheta * sinphi,
628 -1.0 * p1_omega * costheta};
629
630 // third child kinematics in parent meson rest frame
631 e3_pion = (pmass_omega_dalitz * pmass_omega_dalitz + omass_pion * omass_pion - epmass_omega_dalitz * epmass_omega_dalitz)/(2. * pmass_omega_dalitz);
632 p3_pion = TMath::Sqrt((e3_pion + omass_pion) * (e3_pion - omass_pion));
633
634 // third child 4-vector in parent meson rest frame
635 fProducts_omega_dalitz[2].SetPx(p3_pion * sintheta * cosphi);
636 fProducts_omega_dalitz[2].SetPy(p3_pion * sintheta * sinphi);
637 fProducts_omega_dalitz[2].SetPz(p3_pion * costheta);
638 fProducts_omega_dalitz[2].SetE(e3_pion);
639
640 // lepton 4-vectors in properly rotated virtual photon rest frame
641 Double_t pRot1_omega_dalitz[3] = {0.};
642 Rot(pProd1_omega_dalitz, pRot1_omega_dalitz, costheta, -sintheta, -cosphi, -sinphi);
643 Double_t pRot2_omega_dalitz[3] = {0.};
644 Rot(pProd2_omega_dalitz, pRot2_omega_dalitz, costheta, -sintheta, -cosphi, -sinphi);
645 fProducts_omega_dalitz[0].SetPx(pRot1_omega_dalitz[0]);
646 fProducts_omega_dalitz[0].SetPy(pRot1_omega_dalitz[1]);
647 fProducts_omega_dalitz[0].SetPz(pRot1_omega_dalitz[2]);
648 fProducts_omega_dalitz[0].SetE(e1_omega);
649 fProducts_omega_dalitz[1].SetPx(pRot2_omega_dalitz[0]);
650 fProducts_omega_dalitz[1].SetPy(pRot2_omega_dalitz[1]);
651 fProducts_omega_dalitz[1].SetPz(pRot2_omega_dalitz[2]);
652 fProducts_omega_dalitz[1].SetE(e1_omega);
653
654 // boost the dielectron into the parent meson's rest frame
655 Double_t eLPparent_omega = TMath::Sqrt(p3_pion * p3_pion + epmass_omega_dalitz * epmass_omega_dalitz);
656 TVector3 boostPair_omega( -1.0 * fProducts_omega_dalitz[2].Px() / eLPparent_omega,
657 -1.0 * fProducts_omega_dalitz[2].Py() / eLPparent_omega,
658 -1.0 * fProducts_omega_dalitz[2].Pz() / eLPparent_omega);
659 fProducts_omega_dalitz[0].Boost(boostPair_omega);
660 fProducts_omega_dalitz[1].Boost(boostPair_omega);
661
662 // boost all decay products into the lab frame
663 TVector3 boostLab_omega_dalitz(pparent->Px() / pparent->E(),
664 pparent->Py() / pparent->E(),
665 pparent->Pz() / pparent->E());
666
667 fProducts_omega_dalitz[0].Boost(boostLab_omega_dalitz);
668 fProducts_omega_dalitz[1].Boost(boostLab_omega_dalitz);
669 fProducts_omega_dalitz[2].Boost(boostLab_omega_dalitz);
670
671
672//-----------------------------------------------------------------------------//
673// Generate Omega resonance decay //
674//-----------------------------------------------------------------------------//
675
676 if(wp_omega!=0.0){
677 // calculate omega mass
678 mp_omega = pparent->M();
679 }
680 else{
681 Double_t x_omega=pparent->Px(); Double_t y_omega=pparent->Py(); Double_t z_omega=pparent->Pz();
682 Double_t t_omega=pparent->E();
683 Double_t p_omega=x_omega*x_omega+y_omega*y_omega+z_omega*z_omega;
684 Double_t Q2_omega= abs((t_omega*t_omega)-(p_omega*p_omega));
685 mp_omega = sqrt(Q2_omega);
686 }
687
688 // daughter
689 if ( mp_omega< 2.*md_omega )
690 {
691 printf("Omega into ee Decay kinematically impossible! \n");
692 return;
693 }
694
695 for( ;; ) {
696 // Sample the electron pair mass from a histogram
697 epmass_omega = fEPMassOmega->GetRandom();
698 if( mp_omega < 2.*epmass_omega ) break;
699 }
700
701 // electron pair kinematics in virtual photon rest frame
702 Ed_omega = epmass_omega/2.;
703 pd_omega = TMath::Sqrt((Ed_omega+md_omega)*(Ed_omega-md_omega));
704
705 // momentum vectors of electrons in virtual photon rest frame
706 Double_t pProd1_omega[3] = {pd_omega * sintheta * cosphi,
707 pd_omega * sintheta * sinphi,
708 pd_omega * costheta};
709
710 Double_t pProd2_omega[3] = {-1.0 * pd_omega * sintheta * cosphi,
711 -1.0 * pd_omega * sintheta * sinphi,
712 -1.0 * pd_omega * costheta};
713
714
715 // lepton 4 vectors in properly rotated virtual photon rest frame
716 Double_t pRot1_omega[3] = {0.};
717 Rot(pProd1_omega, pRot1_omega, costheta, -sintheta, -cosphi, -sinphi);
718 Double_t pRot2_omega[3] = {0.};
719 Rot(pProd2_omega, pRot2_omega, costheta, -sintheta, -cosphi, -sinphi);
720 fProducts_omega[0].SetPx(pRot1_omega[0]);
721 fProducts_omega[0].SetPy(pRot1_omega[1]);
722 fProducts_omega[0].SetPz(pRot1_omega[2]);
723 fProducts_omega[0].SetE(Ed_omega);
724 fProducts_omega[1].SetPx(pRot2_omega[0]);
725 fProducts_omega[1].SetPy(pRot2_omega[1]);
726 fProducts_omega[1].SetPz(pRot2_omega[2]);
727 fProducts_omega[1].SetE(Ed_omega);
728
729 // boost decay products into the lab frame
730 TVector3 boostLab_omega(pparent->Px() / pparent->E(),
731 pparent->Py() / pparent->E(),
732 pparent->Pz() / pparent->E());
733
734 fProducts_omega[0].Boost(boostLab_omega);
735 fProducts_omega[1].Boost(boostLab_omega);
736
737 }
738
739//-----------------------------------------------------------------------------//
740// Generate Etaprime Dalitz decay //
741//-----------------------------------------------------------------------------//
742
743 else if(idpart==331){
744 pmass_etaprime = pparent->M();
745 for(;;){
746 // Sample the electron pair mass from a histogram
747 epmass_etaprime = fEPMassEtaPrime->GetRandom();
748 if(pmass_etaprime-omass_gamma>epmass_etaprime && epmass_etaprime/2.>emass)
749 break;}
750
751 // electron pair kinematics in virtual photon rest frame
752 e1_etaprime = epmass_etaprime / 2.;
753 p1_etaprime = TMath::Sqrt((e1_etaprime + emass) * (e1_etaprime - emass));
754
755 // momentum vectors of electrons in virtual photon rest frame
756 Double_t pProd1_etaprime[3] = {p1_etaprime * sintheta * cosphi,
757 p1_etaprime * sintheta * sinphi,
758 p1_etaprime * costheta};
759 Double_t pProd2_etaprime[3] = {-1.0 * p1_etaprime * sintheta * cosphi,
760 -1.0 * p1_etaprime * sintheta * sinphi,
761 -1.0 * p1_etaprime * costheta};
762
763 // third child kinematics in parent meson rest frame
764 e3_gamma_etaprime = (pmass_etaprime * pmass_etaprime + omass_gamma * omass_gamma - epmass_etaprime * epmass_etaprime)/(2. * pmass_etaprime);
765 p3_gamma_etaprime = TMath::Sqrt((e3_gamma_etaprime + omass_gamma) * (e3_gamma_etaprime - omass_gamma));
766
767 // third child 4-vector in parent meson rest frame
768 fProducts_etaprime[2].SetPx(p3_gamma_etaprime * sintheta * cosphi);
769 fProducts_etaprime[2].SetPy(p3_gamma_etaprime * sintheta * sinphi);
770 fProducts_etaprime[2].SetPz(p3_gamma_etaprime * costheta);
771 fProducts_etaprime[2].SetE(e3_gamma_etaprime);
772
773 // electron 4-vectors in properly rotated virtual photon rest frame
774 Double_t pRot1_etaprime[3] = {0.};
775 Rot(pProd1_etaprime, pRot1_etaprime, costheta, -sintheta, -cosphi, -sinphi);
776 Double_t pRot2_etaprime[3] = {0.};
777 Rot(pProd2_etaprime, pRot2_etaprime, costheta, -sintheta, -cosphi, -sinphi);
778 fProducts_etaprime[0].SetPx(pRot1_etaprime[0]);
779 fProducts_etaprime[0].SetPy(pRot1_etaprime[1]);
780 fProducts_etaprime[0].SetPz(pRot1_etaprime[2]);
781 fProducts_etaprime[0].SetE(e1_etaprime);
782 fProducts_etaprime[1].SetPx(pRot2_etaprime[0]);
783 fProducts_etaprime[1].SetPy(pRot2_etaprime[1]);
784 fProducts_etaprime[1].SetPz(pRot2_etaprime[2]);
785 fProducts_etaprime[1].SetE(e1_etaprime);
786
787 // boost the dielectron into the parent meson's rest frame
788 Double_t eLPparent_etaprime = TMath::Sqrt(p3_gamma_etaprime * p3_gamma_etaprime + epmass_etaprime * epmass_etaprime);
789 TVector3 boostPair_etaprime( -1.0 * fProducts_etaprime[2].Px() / eLPparent_etaprime,
790 -1.0 * fProducts_etaprime[2].Py() / eLPparent_etaprime,
791 -1.0 * fProducts_etaprime[2].Pz() / eLPparent_etaprime);
792 fProducts_etaprime[0].Boost(boostPair_etaprime);
793 fProducts_etaprime[1].Boost(boostPair_etaprime);
794
795 // boost all decay products into the lab frame
796 TVector3 boostLab_etaprime(pparent->Px() / pparent->E(),
797 pparent->Py() / pparent->E(),
798 pparent->Pz() / pparent->E());
799
800 fProducts_etaprime[0].Boost(boostLab_etaprime);
801 fProducts_etaprime[1].Boost(boostLab_etaprime);
802 fProducts_etaprime[2].Boost(boostLab_etaprime);
803
804 }
805
806//-----------------------------------------------------------------------------//
807// Generate Phi Dalitz decay //
808//-----------------------------------------------------------------------------//
809
810 else if(idpart==333){
811 pmass_phi_dalitz = pparent->M();
812 for(;;){
813 // Sample the electron pair mass from a histogram
814 epmass_phi_dalitz = fEPMassPhiDalitz->GetRandom();
815 if(pmass_phi_dalitz-omass_eta>epmass_phi_dalitz && epmass_phi_dalitz/2.>emass)
816 break;}
817
818 // electron pair kinematics in virtual photon rest frame
819 e1_phi = epmass_phi_dalitz / 2.;
820 p1_phi = TMath::Sqrt((e1_phi + emass) * (e1_phi - emass));
821
822 // momentum vectors of electrons in virtual photon rest frame
823 Double_t pProd1_phi_dalitz[3] = {p1_phi * sintheta * cosphi,
824 p1_phi * sintheta * sinphi,
825 p1_phi * costheta};
826 Double_t pProd2_phi_dalitz[3] = {-1.0 * p1_phi * sintheta * cosphi,
827 -1.0 * p1_phi * sintheta * sinphi,
828 -1.0 * p1_phi * costheta};
829
830 // third child kinematics in parent meson rest frame
831 e3_eta = (pmass_phi_dalitz * pmass_phi_dalitz + omass_eta * omass_eta - epmass_phi_dalitz * epmass_phi_dalitz)/(2. * pmass_phi_dalitz);
832 p3_eta = TMath::Sqrt((e3_eta + omass_eta) * (e3_eta - omass_eta));
833
834 // third child 4-vector in parent meson rest frame
835 fProducts_phi_dalitz[2].SetPx(p3_eta * sintheta * cosphi);
836 fProducts_phi_dalitz[2].SetPy(p3_eta * sintheta * sinphi);
837 fProducts_phi_dalitz[2].SetPz(p3_eta * costheta);
838 fProducts_phi_dalitz[2].SetE(e3_eta);
839
840 // electron 4-vectors in properly rotated virtual photon rest frame
841 Double_t pRot1_phi_dalitz[3] = {0.};
842 Rot(pProd1_phi_dalitz, pRot1_phi_dalitz, costheta, -sintheta, -cosphi, -sinphi);
843 Double_t pRot2_phi_dalitz[3] = {0.};
844 Rot(pProd2_phi_dalitz, pRot2_phi_dalitz, costheta, -sintheta, -cosphi, -sinphi);
845 fProducts_phi_dalitz[0].SetPx(pRot1_phi_dalitz[0]);
846 fProducts_phi_dalitz[0].SetPy(pRot1_phi_dalitz[1]);
847 fProducts_phi_dalitz[0].SetPz(pRot1_phi_dalitz[2]);
848 fProducts_phi_dalitz[0].SetE(e1_phi);
849 fProducts_phi_dalitz[1].SetPx(pRot2_phi_dalitz[0]);
850 fProducts_phi_dalitz[1].SetPy(pRot2_phi_dalitz[1]);
851 fProducts_phi_dalitz[1].SetPz(pRot2_phi_dalitz[2]);
852 fProducts_phi_dalitz[1].SetE(e1_phi);
853
854 // boost the dielectron into the parent meson's rest frame
855 Double_t eLPparent_phi = TMath::Sqrt(p3_eta * p3_eta + epmass_phi_dalitz * epmass_phi_dalitz);
856 TVector3 boostPair_phi( -1.0 * fProducts_phi_dalitz[2].Px() / eLPparent_phi,
857 -1.0 * fProducts_phi_dalitz[2].Py() / eLPparent_phi,
858 -1.0 * fProducts_phi_dalitz[2].Pz() / eLPparent_phi);
859 fProducts_phi_dalitz[0].Boost(boostPair_phi);
860 fProducts_phi_dalitz[1].Boost(boostPair_phi);
861
862 // boost all decay products into the lab frame
863 TVector3 boostLab_phi_dalitz(pparent->Px() / pparent->E(),
864 pparent->Py() / pparent->E(),
865 pparent->Pz() / pparent->E());
866
867 fProducts_phi_dalitz[0].Boost(boostLab_phi_dalitz);
868 fProducts_phi_dalitz[1].Boost(boostLab_phi_dalitz);
869 fProducts_phi_dalitz[2].Boost(boostLab_phi_dalitz);
870
871
872//-----------------------------------------------------------------------------//
873// Generate Phi resonance decay //
874//-----------------------------------------------------------------------------//
875
876 if(wp_phi!=0.0){
877 // calculate phi mass
878 mp_phi = pparent->M();
879 }
880 else{
881 Double_t x_phi=pparent->Px(); Double_t y_phi=pparent->Py(); Double_t z_phi=pparent->Pz();
882 Double_t t_phi=pparent->E();
883 Double_t p_phi=x_phi*x_phi+y_phi*y_phi+z_phi*z_phi;
884 Double_t Q2_phi= abs((t_phi*t_phi)-(p_phi*p_phi));
885 mp_phi = sqrt(Q2_phi);
886 }
887
888 if ( mp_phi< 2.*md_phi )
889 {
890 printf("Phi into ee Decay kinematically impossible! \n");
891 return;
892 }
893
894 for( ;; ) {
895 // Sample the electron pair mass from a histogram
896 epmass_phi = fEPMassPhi->GetRandom();
897 if(mp_phi < 2.*epmass_phi) break;
898 }
899
900 // electron pair kinematics in virtual photon rest frame
901 Ed_phi = epmass_phi/2.;
902 pd_phi = TMath::Sqrt((Ed_phi+md_phi)*(Ed_phi-md_phi));
903
904 // momentum vectors of electrons in virtual photon rest frame
905 Double_t pProd1_phi[3] = {pd_phi * sintheta * cosphi,
906 pd_phi * sintheta * sinphi,
907 pd_phi * costheta};
908 Double_t pProd2_phi[3] = {-1.0 * pd_phi * sintheta * cosphi,
909 -1.0 * pd_phi * sintheta * sinphi,
910 -1.0 * pd_phi * costheta};
911
912 // electron 4 vectors in properly rotated virtual photon rest frame
913 Double_t pRot1_phi[3] = {0.};
914 Rot(pProd1_phi, pRot1_phi, costheta, -sintheta, -cosphi, -sinphi);
915 Double_t pRot2_phi[3] = {0.};
916 Rot(pProd2_phi, pRot2_phi, costheta, -sintheta, -cosphi, -sinphi);
917 fProducts_phi[0].SetPx(pRot1_phi[0]);
918 fProducts_phi[0].SetPy(pRot1_phi[1]);
919 fProducts_phi[0].SetPz(pRot1_phi[2]);
920 fProducts_phi[0].SetE(Ed_phi);
921 fProducts_phi[1].SetPx(pRot2_phi[0]);
922 fProducts_phi[1].SetPy(pRot2_phi[1]);
923 fProducts_phi[1].SetPz(pRot2_phi[2]);
924 fProducts_phi[1].SetE(Ed_phi);
925
926 // boost decay products into the lab frame
927 TVector3 boostLab_phi(pparent->Px() / pparent->E(),
928 pparent->Py() / pparent->E(),
929 pparent->Pz() / pparent->E());
930
931 fProducts_phi[0].Boost(boostLab_phi);
932 fProducts_phi[1].Boost(boostLab_phi);
933
934 }
935
936//-----------------------------------------------------------------------------//
937// Generate Jpsi resonance decay //
938//-----------------------------------------------------------------------------//
939
940 else if(idpart==443){
941 // calculate jpsi mass
942 if(wp_jpsi!=0.0){
943 mp_jpsi = pparent->M();
944 }
945 else{
76e6e4c5 946 /*Double_t x_jpsi=pparent->Px();
947 Double_t y_jpsi=pparent->Py();
948 Double_t z_jpsi=pparent->Pz();
949 Double_t t_jpsi=pparent->E();
950 Double_t p_jpsi=x_jpsi*x_jpsi+y_jpsi*y_jpsi+z_jpsi*z_jpsi;
951 Double_t Q2_jpsi= abs((t_jpsi*t_jpsi)-(p_jpsi*p_jpsi));
952 mp_jpsi = sqrt(Q2_jpsi);*/
953
954 mp_jpsi = 3.096;
b5c4afc6 955
956 }
957
958 // daughter
959 if ( mp_jpsi < 2.*md_jpsi )
960 {
961 printf("JPsi into ee Decay kinematically impossible! \n");
962 return;
963 }
964
965 for( ;; ) {
966 // Sample the electron pair mass from a histogram
967 epmass_jpsi = fEPMassJPsi->GetRandom();
968 if ( mp_jpsi < 2.*epmass_jpsi ) break;
969 }
970 // electron pair kinematics in virtual photon rest frame
971 Ed_jpsi = epmass_jpsi/2.;
972 pd_jpsi = TMath::Sqrt((Ed_jpsi+md_jpsi)*(Ed_jpsi-md_jpsi));
973
974 // momentum vectors of electrons in virtual photon rest frame
975 Double_t pProd1_jpsi[3] = {pd_jpsi * sintheta * cosphi,
976 pd_jpsi * sintheta * sinphi,
977 pd_jpsi * costheta};
978
979 Double_t pProd2_jpsi[3] = {-1.0 * pd_jpsi * sintheta * cosphi,
980 -1.0 * pd_jpsi * sintheta * sinphi,
981 -1.0 * pd_jpsi * costheta};
982
983
984 // electron 4 vectors in properly rotated virtual photon rest frame
985 Double_t pRot1_jpsi[3] = {0.};
986 Rot(pProd1_jpsi, pRot1_jpsi, costheta, -sintheta, -cosphi, -sinphi);
987 Double_t pRot2_jpsi[3] = {0.};
988 Rot(pProd2_jpsi, pRot2_jpsi, costheta, -sintheta, -cosphi, -sinphi);
989 fProducts_jpsi[0].SetPx(pRot1_jpsi[0]);
990 fProducts_jpsi[0].SetPy(pRot1_jpsi[1]);
991 fProducts_jpsi[0].SetPz(pRot1_jpsi[2]);
992 fProducts_jpsi[0].SetE(Ed_jpsi);
993 fProducts_jpsi[1].SetPx(pRot2_jpsi[0]);
994 fProducts_jpsi[1].SetPy(pRot2_jpsi[1]);
995 fProducts_jpsi[1].SetPz(pRot2_jpsi[2]);
996 fProducts_jpsi[1].SetE(Ed_jpsi);
997
998
999 // boost decay products into the lab frame
1000 TVector3 boostLab_jpsi(pparent->Px() / pparent->E(),
1001 pparent->Py() / pparent->E(),
1002 pparent->Pz() / pparent->E());
1003
1004 fProducts_jpsi[0].Boost(boostLab_jpsi);
1005 fProducts_jpsi[1].Boost(boostLab_jpsi);
1006
1007 }
1008
1009 return;
1010}
1011
1012void AliDecayerExodus::Rot(Double_t pin[3], Double_t pout[3], Double_t costheta, Double_t sintheta,
1013 Double_t cosphi, Double_t sinphi) const
1014{
1015// Perform rotation
1016 pout[0] = pin[0]*costheta*cosphi-pin[1]*sinphi+pin[2]*sintheta*cosphi;
1017 pout[1] = pin[0]*costheta*sinphi+pin[1]*cosphi+pin[2]*sintheta*sinphi;
1018 pout[2] = -1.0 * pin[0] * sintheta + pin[2] * costheta;
1019 return;
1020}
1021
1022
1023Int_t AliDecayerExodus::ImportParticles(TClonesArray *particles)
1024{
1025//
1026// Import particles for Dalitz and resonance decays
1027//
1028
1029 TClonesArray &clonesParticles = *particles;
1030
1031 Int_t i, k;
1032 Double_t px, py, pz, e;
1033
1034 Int_t pdgD [3][3] = { {kElectron, -kElectron, 22}, // pizero, eta, etaprime
1035 {kElectron, -kElectron, 111}, // omega dalitz
1036 {kElectron, -kElectron, 221} }; // phi dalitz
1037
1038 Int_t pdgR [2] = {kElectron, -kElectron}; // rho, omega, phi, jpsi
1039
1040
1041
1042 Int_t parentD[3] = { 0, 0, -1};
1043 Int_t dauD1 [3] = {-1, -1, 1};
1044 Int_t dauD2 [3] = {-1, -1, 2};
1045
1046 Int_t parentR[2] = { 0, 0};
1047 Int_t dauR1 [2] = { -1, -1};
1048 Int_t dauR2 [2] = { -1, -1};
1049
1050 for (Int_t j = 0; j < 9; j++){
1051
1052 // pizero
1053 if(j==0){
1054 for (i = 2; i > -1; i--) {
1055 px = fProducts_pion[i].Px();
1056 py = fProducts_pion[i].Py();
1057 pz = fProducts_pion[i].Pz();
1058 e = fProducts_pion[i].E();
1059 new(clonesParticles[2 - i]) TParticle(pdgD[0][i], 1, parentD[i], -1, dauD1[i], dauD2[i], px, py, pz, e, 0., 0., 0., 0.);
1060 }
1061 return (3);
1062 }
1063
1064 // rho
1065 else if(j==1){
1066 for (k = 1; k > -1; k--) {
1067 px = fProducts_rho[k].Px();
1068 py = fProducts_rho[k].Py();
1069 pz = fProducts_rho[k].Pz();
1070 e = fProducts_rho[k].E();
1071 new(clonesParticles[1 - k]) TParticle(pdgR[k], 1, parentR[k], -1, dauR1[k], dauR2[k], px, py, pz, e, 0., 0., 0., 0.);
1072 }
1073 return (2);
1074 }
1075
1076 // eta
1077 else if(j==2){
1078 for (i = 2; i > -1; i--) {
1079 px = fProducts_eta[i].Px();
1080 py = fProducts_eta[i].Py();
1081 pz = fProducts_eta[i].Pz();
1082 e = fProducts_eta[i].E();
1083 new(clonesParticles[2 - i]) TParticle(pdgD[0][i], 1, parentD[i], -1, dauD1[i], dauD2[i], px, py, pz, e, 0., 0., 0., 0.);
1084 }
1085 return (3);
1086 }
1087
1088 // omega dalitz
1089 else if(j==3){
1090 for (i = 2; i > -1; i--) {
1091 px = fProducts_omega_dalitz[i].Px();
1092 py = fProducts_omega_dalitz[i].Py();
1093 pz = fProducts_omega_dalitz[i].Pz();
1094 e = fProducts_omega_dalitz[i].E();
1095 new(clonesParticles[2 - i]) TParticle(pdgD[1][i], 1, parentD[i], -1, dauD1[i], dauD2[i], px, py, pz, e, 0., 0., 0., 0.);
1096 }
1097 return (3);
1098 }
1099
1100 // omega direct
1101 else if(j==4){
1102 for (k = 1; k > -1; k--) {
1103 px = fProducts_rho[k].Px();
1104 py = fProducts_rho[k].Py();
1105 pz = fProducts_rho[k].Pz();
1106 e = fProducts_rho[k].E();
1107 new(clonesParticles[1 - k]) TParticle(pdgR[k], 1, parentR[k], -1, dauR1[k], dauR2[k], px, py, pz, e, 0., 0., 0., 0.);
1108 }
1109 return (2);
1110 }
1111
1112 // etaprime
1113 else if(j==5){
1114 for (i = 2; i > -1; i--) {
1115 px = fProducts_etaprime[i].Px();
1116 py = fProducts_etaprime[i].Py();
1117 pz = fProducts_etaprime[i].Pz();
1118 e = fProducts_etaprime[i].E();
1119 new(clonesParticles[2 - i]) TParticle(pdgD[0][i], 1, parentD[i], -1, dauD1[i], dauD2[i], px, py, pz, e, 0., 0., 0., 0.);
1120 }
1121 return (3);
1122 }
1123
1124 // phi dalitz
1125 else if(j==6){
1126 for (i = 2; i > -1; i--) {
1127 px = fProducts_phi_dalitz[i].Px();
1128 py = fProducts_phi_dalitz[i].Py();
1129 pz = fProducts_phi_dalitz[i].Pz();
1130 e = fProducts_phi_dalitz[i].E();
1131 new(clonesParticles[2 - i]) TParticle(pdgD[2][i], 1, parentD[i], -1, dauD1[i], dauD2[i], px, py, pz, e, 0., 0., 0., 0.);
1132 }
1133 return (3);
1134 }
1135
1136
1137 // phi direct
1138 else if(j==7){
1139 for (k = 1; k > -1; k--) {
1140 px = fProducts_phi[k].Px();
1141 py = fProducts_phi[k].Py();
1142 pz = fProducts_phi[k].Pz();
1143 e = fProducts_phi[k].E();
1144 new(clonesParticles[1 - k]) TParticle(pdgR[k], 1, parentR[k], -1, dauR1[k], dauR2[k], px, py, pz, e, 0., 0., 0., 0.);
1145 }
1146 return (2);
1147 }
1148
1149 // jpsi direct
1150 else if(j==8){
1151 for (k = 1; k > -1; k--) {
1152 px = fProducts_jpsi[k].Px();
1153 py = fProducts_jpsi[k].Py();
1154 pz = fProducts_jpsi[k].Pz();
1155 e = fProducts_jpsi[k].E();
1156 new(clonesParticles[1 - k]) TParticle(pdgR[k], 1, parentR[k], -1, dauR1[k], dauR2[k], px, py, pz, e, 0., 0., 0., 0.);
1157 }
1158 return (2);
1159 }
1160
1161 }
1162
1163 return particles->GetEntries();
1164
1165}
1166
1167
1168void AliDecayerExodus::Decay(TClonesArray *array)
1169{
1170 // Replace all Dalitz(pi0,eta,omega,eta',phi) and resonance(rho,omega,phi,jpsi) decays with the correct matrix element decays
1171 // for di-electron cocktail calculations
1172
1173
1174 Int_t nt = array->GetEntriesFast();
1175 TParticle* dp3[3];
1176 TParticle* dp2[2];
1177 Int_t fd3, ld3, fd2, ld2, fd, ld;
1178 Int_t j, k;
1179
1180 for (Int_t i = 0; i < nt; i++) {
1181 TParticle* part = (TParticle*) (array->At(i));
1182 if (part->GetPdgCode() != 111 || part->GetPdgCode() != 221 || part->GetPdgCode() != 223 || part->GetPdgCode() != 331 || part->GetPdgCode() != 333 || part->GetPdgCode() != 443 ) continue;
1183
1184 //
1185 // Pizero Dalitz
1186 //
1187 if(part->GetPdgCode() == 111){
1188
1189 fd3 = part->GetFirstDaughter() - 1;
1190 ld3 = part->GetLastDaughter() - 1;
1191
1192 if (fd3 < 0) continue;
1193 if ((ld3 - fd3) != 2) continue;
1194
1195 for (j = 0; j < 3; j++) dp3[j] = (TParticle*) (array->At(fd3+j));
1196
1197 if((dp3[0]->GetPdgCode() != 22) && (TMath::Abs(dp3[1]->GetPdgCode()) != 11)) continue;
1198
1199 TLorentzVector Pizero(part->Px(), part->Py(), part->Pz(), part->Energy());
1200 Decay(111, &Pizero);
1201 for (j = 0; j < 3; j++) dp3[j]->SetMomentum(fProducts_pion[2-j]);
1202 }
1203
1204
1205 //
1206 // Eta Dalitz
1207 //
1208
1209 if(part->GetPdgCode() == 221){
1210
1211 fd3 = part->GetFirstDaughter() - 1;
1212 ld3 = part->GetLastDaughter() - 1;
1213
1214 if (fd3 < 0) continue;
1215 if ((ld3 - fd3) != 2) continue;
1216
1217 for (j = 0; j < 3; j++) dp3[j] = (TParticle*) (array->At(fd3+j));
1218
1219 if((dp3[0]->GetPdgCode() != 22) && ((TMath::Abs(dp3[1]->GetPdgCode()) != 11))) continue;
1220
1221 TLorentzVector Eta(part->Px(), part->Py(), part->Pz(), part->Energy());
1222 Decay(221, &Eta);
1223 for (j = 0; j < 3; j++) dp3[j]->SetMomentum(fProducts_eta[2-j]);
1224 }
1225
1226 //
1227 // Rho
1228 //
1229
1230 if(part->GetPdgCode() == 113){
1231
1232 fd2 = part->GetFirstDaughter() - 1;
1233 ld2 = part->GetLastDaughter() - 1;
1234
1235 if (fd2 < 0) continue;
1236 if ((ld2 - fd2) != 1) continue;
1237
1238 for (k = 0; k < 2; k++) dp2[k] = (TParticle*) (array->At(fd2+k));
1239
1240 if((dp2[0]->GetPdgCode() != 11) && ((TMath::Abs(dp2[1]->GetPdgCode()) != 11))) continue;
1241
1242 TLorentzVector Rho(part->Px(), part->Py(), part->Pz(), part->Energy());
1243 Decay(113, &Rho);
1244 for (k = 0; k < 2; k++) dp2[k]->SetMomentum(fProducts_rho[1-k]);
1245 }
1246
1247 //
1248 // Omega dalitz and direct
1249 //
1250
1251 if(part->GetPdgCode() == 223){
1252
1253 fd = part->GetFirstDaughter() - 1;
1254 ld = part->GetLastDaughter() - 1;
1255
1256 if (fd < 0) continue;
1257
1258 if ((ld - fd) == 2){
1259
1260 for (j = 0; j < 3; j++) dp3[j] = (TParticle*) (array->At(fd+j));
1261 if( dp3[0]->GetPdgCode() != 111 && (TMath::Abs(dp3[1]->GetPdgCode()) != 11)) continue;
1262
1263 TLorentzVector Omegadalitz(part->Px(), part->Py(), part->Pz(), part->Energy());
1264 Decay(223, &Omegadalitz);
1265 for (j = 0; j < 3; j++) dp3[j]->SetMomentum(fProducts_omega_dalitz[2-j]);
1266 }
1267
1268 else if ((ld - fd) == 1) {
1269
1270 for (k = 0; k < 2; k++) dp2[k] = (TParticle*) (array->At(fd+k));
1271 if( dp2[0]->GetPdgCode() != 11 && (TMath::Abs(dp2[1]->GetPdgCode()) != 11)) continue;
1272
1273 TLorentzVector Omega(part->Px(), part->Py(), part->Pz(), part->Energy());
1274 Decay(223, &Omega);
1275 for (k = 0; k < 2; k++) dp2[k]->SetMomentum(fProducts_omega[1-k]);
1276 }
1277 }
1278
1279 //
1280 // Etaprime dalitz
1281 //
1282
1283 if(part->GetPdgCode() == 331){
1284
1285 fd3 = part->GetFirstDaughter() - 1;
1286 ld3 = part->GetLastDaughter() - 1;
1287
1288 if (fd3 < 0) continue;
1289 if ((ld3 - fd3) != 2) continue;
1290
1291 for (j = 0; j < 3; j++) dp3[j] = (TParticle*) (array->At(fd3+j));
1292
1293 if((dp3[0]->GetPdgCode() != 22) && ((TMath::Abs(dp3[1]->GetPdgCode()) != 11))) continue;
1294
1295 TLorentzVector Etaprime(part->Px(), part->Py(), part->Pz(), part->Energy());
1296 Decay(331, &Etaprime);
1297 for (j = 0; j < 3; j++) dp3[j]->SetMomentum(fProducts_etaprime[2-j]);
1298 }
1299
1300 //
1301 // Phi dalitz and direct
1302 //
1303 if(part->GetPdgCode() == 333){
1304
1305 fd = part->GetFirstDaughter() - 1;
1306 ld = part->GetLastDaughter() - 1;
1307
1308 if (fd < 0) continue;
1309 if ((ld - fd) == 2){
1310 for (j = 0; j < 3; j++) dp3[j] = (TParticle*) (array->At(fd+j));
1311 if( dp3[0]->GetPdgCode() != 221 && (TMath::Abs(dp3[1]->GetPdgCode()) != 11)) continue;
1312
1313 TLorentzVector Phidalitz(part->Px(), part->Py(), part->Pz(), part->Energy());
1314 Decay(333, &Phidalitz);
1315 for (j = 0; j < 3; j++) dp3[j]->SetMomentum(fProducts_phi_dalitz[2-j]);
1316 }
1317
1318 else if ((ld - fd) == 1) {
1319 for (k = 0; k < 2; k++) dp2[k] = (TParticle*) (array->At(fd+k));
1320 if( dp2[0]->GetPdgCode() != 11 && (TMath::Abs(dp2[1]->GetPdgCode()) != 11)) continue;
1321
1322 TLorentzVector Phi(part->Px(), part->Py(), part->Pz(), part->Energy());
1323 Decay(333, &Phi);
1324 for (k = 0; k < 2; k++) dp2[k]->SetMomentum(fProducts_phi[1-k]);
1325 }
1326 }
1327
1328 //
1329 // JPsi
1330 //
1331
1332 if(part->GetPdgCode() == 443){
1333
1334 fd2 = part->GetFirstDaughter() - 1;
1335 ld2 = part->GetLastDaughter() - 1;
1336
1337 if (fd2 < 0) continue;
1338 if ((ld2 - fd2) != 1) continue;
1339
1340 for (k = 0; k < 2; k++) dp2[k] = (TParticle*) (array->At(fd2+k));
1341
1342 if((dp2[0]->GetPdgCode() != 11) && ((TMath::Abs(dp2[1]->GetPdgCode()) != 11))) continue;
1343
1344 TLorentzVector JPsi(part->Px(), part->Py(), part->Pz(), part->Energy());
1345 Decay(443, &JPsi);
1346 for (k = 0; k < 2; k++) dp2[k]->SetMomentum(fProducts_jpsi[1-k]);
1347 }
1348
1349 }
1350}
1351
1352
1353AliDecayerExodus& AliDecayerExodus::operator=(const AliDecayerExodus& rhs)
1354{
1355 // Assignment operator
1356 rhs.Copy(*this);
1357 return *this;
1358}
1359
1360void AliDecayerExodus::Copy(TObject&) const
1361{
1362 //
1363 // Copy
1364 //
1365 Fatal("Copy","Not implemented!\n");
1366}
1367
1368
1369AliDecayerExodus::AliDecayerExodus(const AliDecayerExodus &decayer)
1370 : AliDecayer(),
1371 fEPMassPion(0),
1372 fEPMassEta(0),
1373 fEPMassEtaPrime(0),
1374 fEPMassRho(0),
1375 fEPMassOmega(0),
1376 fEPMassOmegaDalitz(0),
1377 fEPMassPhi(0),
1378 fEPMassPhiDalitz(0),
1379 fEPMassJPsi(0),
1380 fInit(0)
1381{
1382 // Copy Constructor
1383 decayer.Copy(*this);
1384}
1385
1386
1387