1 ///////////////////////////////////////////////////////////////////////////
3 // AliFemtoCoulomb: This is a Coulomb correction class which //
4 // 1. Reads in the dat from a file //
5 // 2. Performs a linear interpolation in R and creates any array of //
7 // 3. Interpolates in eta and returns the Coulomb correction to user //
9 ///////////////////////////////////////////////////////////////////////////
11 #include "AliFemtoCoulomb.h"
12 //#include "Stiostream.h"
15 //#include "PhysicalConstants.h"
16 #define fine_structure_const 0.00729735
19 ClassImp(AliFemtoCoulomb)
22 AliFemtoCoulomb::AliFemtoCoulomb() :
28 // Default constructor
29 fFile = "/afs/rhic/star/hbt/coul/AliFemtoCorrectionFiles/correctionpp.dat";
31 cout << " No file, dummy!" << endl;
34 cout << "You have 1 default Coulomb correction!" << endl;
36 for (int ie=0; ie<1000; ie++) {
42 AliFemtoCoulomb::AliFemtoCoulomb(const AliFemtoCoulomb& aCoul) :
44 fRadius(aCoul.fRadius),
49 CreateLookupTable(fRadius);
52 AliFemtoCoulomb::AliFemtoCoulomb(const char* readFile, const double& radius, const double& charge) :
58 // constructor with explicit filename
61 CreateLookupTable(fRadius);
63 cout << "You have 1 Coulomb correction!" << endl;
66 AliFemtoCoulomb::~AliFemtoCoulomb() {
70 AliFemtoCoulomb& AliFemtoCoulomb::operator=(const AliFemtoCoulomb& aCoul)
72 // assignment operator
77 fRadius = aCoul.fRadius;
80 CreateLookupTable(fRadius);
86 void AliFemtoCoulomb::SetRadius(const double& radius) {
87 // set the coulomb radius
88 cout << " AliFemtoCoulomb::setRadius() " << endl;
90 CreateLookupTable(fRadius);
93 double AliFemtoCoulomb::GetRadius() const {
94 // return coulomb radius
98 void AliFemtoCoulomb::SetFile(const char* readFile) {
99 // set the filename with coulomb calculations
100 cout << " AliFemtoCoulomb::SetFile() " << endl;
102 // Create new lookup table since file has changed
104 CreateLookupTable(fRadius);
108 void AliFemtoCoulomb::SetChargeProduct(const double& charge) {
110 cout << " AliFemtoCoulomb::SetChargeProduct() " << endl;
111 if ( fZ1Z2!=charge ) {
114 fFile = "/afs/rhic/star/hbt/coul/AliFemtoCorrectionFiles/correctionpp.dat";
117 fFile = "/afs/rhic/star/hbt/coul/AliFemtoCorrectionFiles/correctionpm.dat";
119 CreateLookupTable(fRadius);
123 void AliFemtoCoulomb::CreateLookupTable(const double& radius) {
124 // Read radii from fFile
125 // Create array(pair) of linear interpolation between radii
126 cout << " AliFemtoCoulomb::CreateLookupTable() " << endl;
129 cout << " AliFemtoCoulomb::CreateLookupTable -> NEGATIVE RADIUS " << endl;
130 cout << " call AliFemtoCoulomb::SetRadius(r) with positive r " << endl;
131 cerr << " AliFemtoCoulomb::CreateLookupTable -> NEGATIVE RADIUS " << endl;
132 cerr << " call AliFemtoCoulomb::SetRadius(r) with positive r " << endl;
135 ifstream mystream(fFile);
137 cout << "Could not open file" << endl;
141 cout << "Input correction file opened" << endl;
144 static char tempstring[2001];
145 static float radii[2000];
146 static int tNRadii = 0;
148 if (!mystream.getline(tempstring,2000)) {
149 cout << "Could not read radii from file" << endl;
152 for (unsigned int ii=0; ii<strlen(tempstring); ii++) {
153 while (tempstring[ii]==' ') ii++;
154 sscanf(&tempstring[ii++],"%f",&radii[++tNRadii]);
155 while ( tempstring[ii]!=' ' && (ii)<strlen(tempstring) )ii++;
157 cout << " Read " << tNRadii << " radii from file" << endl;
159 static double tLowRadius = -1.0;
160 static double tHighRadius = -1.0;
161 static int tLowIndex = 0;
165 for(int iii=1; iii<=tNRadii-1; iii++) { // Loop to one less than #radii
166 if ( radius >= radii[iii] && radius <= radii[iii+1] ) {
167 tLowRadius = radii[iii];
168 tHighRadius = radii[iii+1];
172 if ( (tLowRadius < 0.0) || (tHighRadius < 0.0) ) {
173 cout << "AliFemtoCoulomb::CreateLookupTable --> Problem interpolating radius" << endl;
174 cout << " Check range of radii in lookup file...." << endl;
175 cerr << "AliFemtoCoulomb::CreateLookupTable --> Problem interpolating radius" << endl;
176 cerr << " Check range of radii in lookup file...." << endl;
180 static double corr[100]; // array of corrections ... must be > tNRadii
182 static double tempEta = 0;
184 while (mystream >> tempEta) {
185 for (int i=1; i<=tNRadii; i++) {
188 static double tLowCoulomb = 0;
189 static double tHighCoulomb = 0;
190 static double nCorr = 0;
191 tLowCoulomb = corr[tLowIndex];
192 tHighCoulomb = corr[tLowIndex+1];
193 nCorr = ( (radius-tLowRadius)*tHighCoulomb+(tHighRadius-radius)*tLowCoulomb )/(tHighRadius-tLowRadius);
194 fEta[fNLines] = tempEta; // Eta
195 fCoulomb[fNLines] = nCorr; // Interpolated Coulomb correction for radius
199 cout << "Lookup Table is created with " << fNLines << " points" << endl;
202 double AliFemtoCoulomb::CoulombCorrect(const double& eta) {
203 // Interpolates in eta
205 cout << "AliFemtoCoulomb::CoulombCorrect(eta) --> Trying to correct for negative radius!" << endl;
206 cerr << "AliFemtoCoulomb::CoulombCorrect(eta) --> Trying to correct for negative radius!" << endl;
210 middle=int( (fNLines-1)/2 );
211 if (eta*fEta[middle]<0.0) {
212 cout << "AliFemtoCoulomb::CoulombCorrect(eta) --> eta: " << eta << " has wrong sign for data file! " << endl;
213 cerr << "AliFemtoCoulomb::CoulombCorrect(eta) --> eta: " << eta << " has wrong sign for data file! " << endl;
217 static double tCorr = 0;
220 if ( (eta>fEta[0]) && (fEta[0]>0.0) ) {
224 if ( (eta<fEta[fNLines-1]) && (fEta[fNLines-1]<0.0) ) {
225 tCorr = fCoulomb[fNLines-1];
228 // This is a binary search for the bracketing pair of data points
231 static int width = 0;
235 middle = int(width/2.0); // Was instantiated above
237 if (fEta[low+middle] < eta) {
238 // eta is in the 1st half
241 middle = int(width/2.0);
244 // eta is in the 2nd half
247 middle = int(width/2.0);
250 // Make sure we found the right one
251 if ( (fEta[low] >= eta) && (eta >= fEta[low+1]) ) {
252 static double tLowEta = 0;
253 static double tHighEta = 0;
254 static double tLowCoulomb = 0;
255 static double tHighCoulomb = 0;
257 tHighEta = fEta[low+1];
258 tLowCoulomb = fCoulomb[low];
259 tHighCoulomb = fCoulomb[low+1];
260 // cout << tLowEta << " *** Eta *** " << tHighEta << endl;
261 // cout << tLowCoulomb << " *** Coulomb *** " << tHighCoulomb << endl;
262 tCorr = ( (eta-tLowEta)*tHighCoulomb+(tHighEta-eta)*tLowCoulomb )/(tHighEta-tLowEta);
265 cout << "AliFemtoCoulomb::CoulombCorrect(eta) --> No correction" << endl;
266 cout << " Check range of eta in file: Input eta " << eta << endl;
267 cerr << "AliFemtoCoulomb::CoulombCorrect(eta) --> No correction" << endl;
268 cerr << " Check range of eta in file: Input eta " << eta << endl;
275 double AliFemtoCoulomb::CoulombCorrect(const double& eta,
276 const double& radius) {
277 // Checks radii ... input radius and fRadius
278 // Calls createLookupTable if neccessary
279 // Interpolate(linear) between etas in the created lookup table
283 // Both radii are negative
284 cout << "AliFemtoCoulomb::CoulombCorrect(eta,r) --> input and member radii are negative!" << endl;
285 cerr << "AliFemtoCoulomb::CoulombCorrect(eta,r) --> input and member radii are negative!" << endl;
291 if (radius == fRadius) {
292 // Both radii are positive and equal
293 // cout << "Radii are the same!!!" << endl;
296 // Both radii are positive but not equal
298 CreateLookupTable(fRadius);
302 // Interpolate in eta
303 return ( CoulombCorrect(eta) );
306 double AliFemtoCoulomb::CoulombCorrect(const AliFemtoPair* pair) {
307 return ( CoulombCorrect( Eta(pair) ) );;
310 double AliFemtoCoulomb::CoulombCorrect(const AliFemtoPair* pair, const double& radius) {
311 return ( CoulombCorrect( Eta(pair),radius ) );
314 double AliFemtoCoulomb::Eta(const AliFemtoPair* pair) {
316 static double px1,py1,pz1,px2,py2,pz2;
317 static double px1new,py1new,pz1new;
318 static double px2new,py2new,pz2new;
319 static double vx1cms,vy1cms,vz1cms;
320 static double vx2cms,vy2cms,vz2cms;
321 static double tVcmsX,tVcmsY,tVcmsZ;
322 static double dv = 0.0;
323 static double e1,e2,e1new,e2new;
324 static double psi,theta;
325 static double beta,gamma;
326 static double tVcmsXnew;
328 px1 = pair->Track1()->FourMomentum().px();
329 py1 = pair->Track1()->FourMomentum().py();
330 pz1 = pair->Track1()->FourMomentum().pz();
331 e1 = pair->Track1()->FourMomentum().e();
332 px2 = pair->Track2()->FourMomentum().px();
333 py2 = pair->Track2()->FourMomentum().py();
334 pz2 = pair->Track2()->FourMomentum().pz();
335 e2 = pair->Track2()->FourMomentum().e();
337 tVcmsX = ( px1+px2 )/( e1+e2 );
338 tVcmsY = ( py1+py2 )/( e1+e2 );
339 tVcmsZ = ( pz1+pz2 )/( e1+e2 );
340 // Rotate tVcms to x-direction
341 psi = atan(tVcmsY/tVcmsX);
342 tVcmsXnew = tVcmsX*cos(psi)+tVcmsY*sin(psi);
344 theta = atan(tVcmsZ/tVcmsX);
345 tVcmsXnew = tVcmsX*cos(theta)+tVcmsZ*sin(theta);
349 gamma = 1.0/::sqrt( 1.0-beta*beta );
351 // Rotate p1 and p2 to new frame
352 px1new = px1*cos(psi)+py1*sin(psi);
353 py1new = -px1*sin(psi)+py1*cos(psi);
355 px1new = px1*cos(theta)+pz1*sin(theta);
356 pz1new = -px1*sin(theta)+pz1*cos(theta);
361 px2new = px2*cos(psi)+py2*sin(psi);
362 py2new = -px2*sin(psi)+py2*cos(psi);
364 px2new = px2*cos(theta)+pz2*sin(theta);
365 pz2new = -px2*sin(theta)+pz2*cos(theta);
370 // Lorentz transform the x component and energy
371 e1new = gamma*e1 - gamma*beta*px1;
372 px1new = -gamma*beta*e1 + gamma*px1;
373 e2new = gamma*e2 - gamma*beta*px2;
374 px2new = -gamma*beta*e2 + gamma*px2;
386 // Velocity difference in CMS frame
387 dv = ::sqrt( (vx1cms-vx2cms)*(vx1cms-vx2cms) +
388 (vy1cms-vy2cms)*(vy1cms-vy2cms) +
389 (vz1cms-vz2cms)*(vz1cms-vz2cms) );
391 return ( fZ1Z2*fine_structure_const/(dv) );
394 TH1D* AliFemtoCoulomb::CorrectionHistogram(const double& mass1, const double& mass2, const int& nBins,
395 const double& low, const double& high) {
396 // return correction histogram
398 if ( mass1!=mass2 ) {
399 cout << "Masses not equal ... try again. No histogram created." << endl;
402 TH1D* correction = new TH1D("correction","Coulomb correction",nBins,low,high);
403 const double kReducedMass = mass1*mass2/(mass1+mass2);
405 //double dQinv = (high-low)/( (double)nBins );
407 for (int ii=1; ii<=nBins; ii++)
409 qInv = correction->GetBinCenter(ii);
410 eta = 2.0*fZ1Z2*kReducedMass*fine_structure_const/( qInv );
411 CoulombCorrect( eta );
412 correction->Fill( qInv, CoulombCorrect(eta,fRadius) );
419 TH1D* AliFemtoCoulomb::CorrectionHistogram(const TH1D* histo, const double mass) {
420 // return correction histogram - 1D case
421 TH1D* correction = (TH1D*) ((TH1D*)histo)->Clone();
423 correction->SetDirectory(0);
424 int nBins = correction->GetXaxis()->GetNbins();
425 const double kReducedMass = 0.5*mass;
428 for (int ii=1; ii<=nBins; ii++)
430 qInv = correction->GetBinCenter(ii);
431 eta = 2.0*fZ1Z2*kReducedMass*fine_structure_const/( qInv );
432 correction->Fill( qInv, CoulombCorrect(eta,fRadius) );
438 TH3D* AliFemtoCoulomb::CorrectionHistogram(const TH3D* histo, const double mass) {
439 // return correction histogram - 3D case
440 TH3D* correction = (TH3D*) ((TH3D*)histo)->Clone();
442 correction->SetDirectory(0);
443 int nBinsX = correction->GetXaxis()->GetNbins();
444 int nBinsY = correction->GetYaxis()->GetNbins();
445 int nBinsZ = correction->GetZaxis()->GetNbins();
446 const double kReducedMass = 0.5*mass;
450 for (int ii=1; ii<=nBinsX; ii++) {
451 for (int iii=1; iii<=nBinsY; iii++) {
452 for (int iv=1; iv<=nBinsZ; iv++) {
453 binNumber = histo->GetBin(ii,iii,iv);
454 qInv = histo->GetBinContent(binNumber);
455 eta = 2.0*fZ1Z2*kReducedMass*fine_structure_const/( qInv );
456 correction->SetBinContent(binNumber, CoulombCorrect(eta,fRadius) );
464 double AliFemtoCoulomb::CoulombCorrect(const double& mass, const double& charge,
465 const double& radius, const double& qInv) {
466 // return correction factor
469 const double kReducedMass = 0.5*mass; // must be same mass particles
470 double eta = 2.0*fZ1Z2*kReducedMass*fine_structure_const/( qInv );
471 return ( CoulombCorrect(eta,fRadius) );