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74ea065c 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 **************************************************************************/
2c770f53 15////////////////////////////////////////////////////////////////////////
16//
17// AliTOFtrack class
18//
19// Authors: Bologna-CERN-ITEP-Salerno Group
20//
21// Description: class for handling ESD extracted tracks for TOF matching.
74ea065c 22/* $Id$ */
23
24#include <Riostream.h>
25#include <TObject.h>
74ea065c 26#include "AliTOFtrack.h"
27#include "AliESDtrack.h"
28
29ClassImp(AliTOFtrack)
30
31//_____________________________________________________________________________
32AliTOFtrack::AliTOFtrack(const AliTOFtrack& t) : AliKalmanTrack(t) {
33 //
34 // Copy constructor.
35 //
36
37 SetSeedIndex(t.GetSeedIndex());
38 SetLabel(t.GetLabel());
39 fSeedLab=t.GetSeedLabel();
40 SetChi2(t.GetChi2());
41
42 fAlpha=t.fAlpha;
43 fX=t.fX;
44
45 fY=t.fY; fZ=t.fZ; fE=t.fE; fT=t.fT; fC=t.fC;
46
47 fCyy=t.fCyy;
48 fCzy=t.fCzy; fCzz=t.fCzz;
49 fCey=t.fCey; fCez=t.fCez; fCee=t.fCee;
50 fCty=t.fCty; fCtz=t.fCtz; fCte=t.fCte; fCtt=t.fCtt;
51 fCcy=t.fCcy; fCcz=t.fCcz; fCce=t.fCce; fCct=t.fCct; fCcc=t.fCcc;
52
53
54}
55
56//_____________________________________________________________________________
57AliTOFtrack::AliTOFtrack(const AliESDtrack& t)
58 :AliKalmanTrack() {
59 //
60 // Constructor from AliESDtrack
61 //
62
63 SetSeedIndex(-1);
64 SetLabel(t.GetLabel());
65 SetChi2(0.);
66 SetMass(t.GetMass());
67
68 fAlpha = t.GetAlpha();
69 if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
70 else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
71 Double_t x, p[5]; t.GetExternalParameters(x,p);
72
73 fX=x;
74
75 x = GetConvConst();
76
77 fY=p[0];
78 fZ=p[1];
79 fT=p[3];
80 fC=p[4]/x;
81 fE=fC*fX - p[2];
82
83 //Conversion of the covariance matrix
84 Double_t c[15]; t.GetExternalCovariance(c);
85
86 c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
87
88 Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
89 Double_t c32=fX*c[13] - c[8];
90 Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
91
92 fCyy=c[0 ];
93 fCzy=c[1 ]; fCzz=c[2 ];
94 fCey=c20; fCez=c21; fCee=c22;
95 fCty=c[6 ]; fCtz=c[7 ]; fCte=c32; fCtt=c[9 ];
96 fCcy=c[10]; fCcz=c[11]; fCce=c42; fCct=c[13]; fCcc=c[14];
97
98 if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
99 StartTimeIntegral();
100 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
101 SetIntegratedLength(t.GetIntegratedLength());
102
103
104}
105//____________________________________________________________________________
106void AliTOFtrack::GetExternalParameters(Double_t& xr, Double_t x[5]) const {
107 //
108 // This function returns external TOF track representation
109 //
110 xr=fX;
111 x[0]=GetY();
112 x[1]=GetZ();
113 x[2]=GetSnp();
114 x[3]=GetTgl();
115 x[4]=Get1Pt();
116}
117
118//_____________________________________________________________________________
119void AliTOFtrack::GetExternalCovariance(Double_t cc[15]) const {
120 //
121 // This function returns external representation of the covriance matrix.
122 //
123 Double_t a=GetConvConst();
124 Double_t c22=fX*fX*fCcc-2*fX*fCce+fCee;
125 Double_t c32=fX*fCct-fCte;
126 Double_t c20=fX*fCcy-fCey, c21=fX*fCcz-fCez, c42=fX*fCcc-fCce;
127
128 cc[0 ]=fCyy;
129 cc[1 ]=fCzy; cc[2 ]=fCzz;
130 cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
131 cc[6 ]=fCty; cc[7 ]=fCtz; cc[8 ]=c32; cc[9 ]=fCtt;
132 cc[10]=fCcy*a; cc[11]=fCcz*a; cc[12]=c42*a; cc[13]=fCct*a; cc[14]=fCcc*a*a;
133
134}
135
136
137//_____________________________________________________________________________
138void AliTOFtrack::GetCovariance(Double_t cc[15]) const {
2c770f53 139 //
140 // Returns the covariance matrix.
141 //
74ea065c 142
143 cc[0]=fCyy;
144 cc[1]=fCzy; cc[2]=fCzz;
145 cc[3]=fCey; cc[4]=fCez; cc[5]=fCee;
146 cc[6]=fCcy; cc[7]=fCcz; cc[8]=fCce; cc[9]=fCcc;
147 cc[10]=fCty; cc[11]=fCtz; cc[12]=fCte; cc[13]=fCct; cc[14]=fCtt;
148
149}
150
151
152//_____________________________________________________________________________
153Int_t AliTOFtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho)
154{
155 // Propagates a track of particle with mass=pm to a reference plane
156 // defined by x=xk through media of density=rho and radiationLength=x0
157
158 if (xk == fX) return 1;
159
160 if (TMath::Abs(fC*xk - fE) >= 0.90000) {
161 return 0;
162 }
163
164 // track Length measurement [SR, GSI, 17.02.2003]
165
166 Double_t oldX = fX, oldY = fY, oldZ = fZ;
167
168 Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fY, z1=fZ;
169 Double_t c1=fC*x1 - fE;
170 if((c1*c1) > 1){
171 return 0;}
172 Double_t r1=sqrt(1.- c1*c1);
173 Double_t c2=fC*x2 - fE;
174 if((c2*c2) > 1) {
175 return 0;
176 }
177 Double_t r2=sqrt(1.- c2*c2);
178
179 fY += dx*(c1+c2)/(r1+r2);
180 fZ += dx*(c1+c2)/(c1*r2 + c2*r1)*fT;
181
182 //f = F - 1
183 Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
184 Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
185 Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
186 Double_t cr=c1*r2+c2*r1;
187 Double_t f12=-dx*fT*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
188 Double_t f13= dx*cc/cr;
189 Double_t f14=dx*fT*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);
190
191 //b = C*ft
192 Double_t b00=f02*fCey + f04*fCcy, b01=f12*fCey + f14*fCcy + f13*fCty;
193 Double_t b10=f02*fCez + f04*fCcz, b11=f12*fCez + f14*fCcz + f13*fCtz;
194 Double_t b20=f02*fCee + f04*fCce, b21=f12*fCee + f14*fCce + f13*fCte;
195 Double_t b30=f02*fCte + f04*fCct, b31=f12*fCte + f14*fCct + f13*fCtt;
196 Double_t b40=f02*fCce + f04*fCcc, b41=f12*fCce + f14*fCcc + f13*fCct;
197
198 //a = f*b = f*C*ft
199 Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;
200
201 //F*C*Ft = C + (a + b + bt)
202 fCyy += a00 + 2*b00;
203 fCzy += a01 + b01 + b10;
204 fCey += b20;
205 fCty += b30;
206 fCcy += b40;
207 fCzz += a11 + 2*b11;
208 fCez += b21;
209 fCtz += b31;
210 fCcz += b41;
211
212 fX=x2;
213
214 //Multiple scattering ******************
215 Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fY)*(y1-fY)+(z1-fZ)*(z1-fZ));
216 Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
217 Double_t beta2=p2/(p2 + GetMass()*GetMass());
218 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
219
220 Double_t ey=fC*fX - fE, ez=fT;
221 Double_t xz=fC*ez, zz1=ez*ez+1, xy=fE+ey;
222
223 fCee += (2*ey*ez*ez*fE+1-ey*ey+ez*ez+fE*fE*ez*ez)*theta2;
224 fCte += ez*zz1*xy*theta2;
225 fCtt += zz1*zz1*theta2;
226 fCce += xz*ez*xy*theta2;
227 fCct += xz*zz1*theta2;
228 fCcc += xz*xz*theta2;
229 /*
230 Double_t dc22 = (1-ey*ey+xz*xz*fX*fX)*theta2;
231 Double_t dc32 = (xz*fX*zz1)*theta2;
232 Double_t dc33 = (zz1*zz1)*theta2;
233 Double_t dc42 = (xz*fX*xz)*theta2;
234 Double_t dc43 = (zz1*xz)*theta2;
235 Double_t dc44 = (xz*xz)*theta2;
236 fCee += dc22;
237 fCte += dc32;
238 fCtt += dc33;
239 fCce += dc42;
240 fCct += dc43;
241 fCcc += dc44;
242 */
243 //Energy losses************************
244 if((5940*beta2/(1-beta2+1e-10) - beta2) < 0){return 0;}
245
246 Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2+1e-10)) - beta2)*d*rho;
247 if (x1 < x2) dE=-dE;
248 cc=fC;
249 fC*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
250 fE+=fX*(fC-cc);
251
252 // track time measurement [SR, GSI 17.02.2002]
253 if (x1 < x2)
254 if (IsStartedTimeIntegral()) {
255 Double_t l2 = (fX-oldX)*(fX-oldX) + (fY-oldY)*(fY-oldY) + (fZ-oldZ)*(fZ-oldZ);
256 AddTimeStep(TMath::Sqrt(l2));
257 }
258
259 return 1;
260}
261
262//_____________________________________________________________________________
263Int_t AliTOFtrack::PropagateToInnerTOF( Bool_t holes)
264{
265 // Propagates a track of particle with mass=pm to a reference plane
266 // defined by x=xk through media of density=rho and radiationLength=x0
267
268
269 Double_t ymax=AliTOFGeometry::RinTOF()*TMath::Tan(0.5*AliTOFGeometry::GetAlpha());
270 Bool_t skip = kFALSE;
2c770f53 271 Double_t y=GetYat(AliTOFGeometry::RinTOF(),skip);
74ea065c 272 if(skip){
273 return 0;
274 }
275 if (y > ymax) {
2c770f53 276 if (!Rotate(AliTOFGeometry::GetAlpha())) {
74ea065c 277 return 0;
278 }
279 } else if (y <-ymax) {
2c770f53 280 if (!Rotate(-AliTOFGeometry::GetAlpha())) {
74ea065c 281 return 0;
282 }
283 }
284
285
2c770f53 286 Double_t x = GetX();
74ea065c 287 Int_t nsteps=Int_t((370.-x)/0.5); // 0.5 cm Steps
288 for (Int_t istep=0;istep<nsteps;istep++){
289 Float_t xp = x+istep*0.5;
290 Double_t param[2];
2c770f53 291 GetPropagationParameters(holes,param);
292 PropagateTo(xp,param[0],param[1]);
74ea065c 293
294 }
295
2c770f53 296 if(!PropagateTo(AliTOFGeometry::RinTOF()))return 0;
74ea065c 297
298 return 1;
299
300}
301
302//_____________________________________________________________________________
303Int_t AliTOFtrack::Rotate(Double_t alpha)
304{
305 // Rotates track parameters in R*phi plane
306
307
308 fAlpha += alpha;
309 if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
310 if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
311
312 Double_t x1=fX, y1=fY;
313 Double_t ca=cos(alpha), sa=sin(alpha);
314 Double_t r1=fC*fX - fE;
315
316 fX = x1*ca + y1*sa;
317 fY =-x1*sa + y1*ca;
318 if((r1*r1) > 1) return 0;
319 fE=fE*ca + (fC*y1 + sqrt(1.- r1*r1))*sa;
320
321 Double_t r2=fC*fX - fE;
322 if (TMath::Abs(r2) >= 0.90000) {
323 cerr<<" AliTOFtrack warning: Rotation failed !\n";
324 return 0;
325 }
326
327 if((r2*r2) > 1) return 0;
328 Double_t y0=fY + sqrt(1.- r2*r2)/fC;
329 if ((fY-y0)*fC >= 0.) {
330 cerr<<" AliTOFtrack warning: Rotation failed !!!\n";
331 return 0;
332 }
333
334 //f = F - 1
335 Double_t f00=ca-1, f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa,
336 f20=fC*sa, f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;
337
338 //b = C*ft
339 Double_t b00=fCyy*f00, b02=fCyy*f20+fCcy*f24+fCey*f22;
340 Double_t b10=fCzy*f00, b12=fCzy*f20+fCcz*f24+fCez*f22;
341 Double_t b20=fCey*f00, b22=fCey*f20+fCce*f24+fCee*f22;
342 Double_t b30=fCty*f00, b32=fCty*f20+fCct*f24+fCte*f22;
343 Double_t b40=fCcy*f00, b42=fCcy*f20+fCcc*f24+fCce*f22;
344
345 //a = f*b = f*C*ft
346 Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;
347
348 //F*C*Ft = C + (a + b + bt)
349 fCyy += a00 + 2*b00;
350 fCzy += b10;
351 fCey += a02+b20+b02;
352 fCty += b30;
353 fCcy += b40;
354 fCez += b12;
355 fCte += b32;
356 fCee += a22 + 2*b22;
357 fCce += b42;
358
359 return 1;
360}
361
2c770f53 362//_________________________________________________________________________
363Double_t AliTOFtrack::GetYat(Double_t xk, Bool_t skip) const {
364//-----------------------------------------------------------------
365// This function calculates the Y-coordinate of a track at the plane x=xk.
366// Needed for matching with the TOF (I.Belikov)
367//-----------------------------------------------------------------
368 skip=kFALSE;
369 Double_t c1=fC*fX - fE, r1=TMath::Sqrt(TMath::Abs(1.- c1*c1));
370 Double_t c2=fC*xk - fE, r2=TMath::Sqrt(TMath::Abs(1.- c2*c2));
371 if( ((1.- c2*c2)<0) || ((1.- c1*c1)<0) ) skip=kTRUE;
372 return fY + (xk-fX)*(c1+c2)/(r1+r2);
373}
74ea065c 374//_________________________________________________________________________
375void AliTOFtrack::GetPxPyPz(Double_t& px, Double_t& py, Double_t& pz) const
376{
377 // Returns reconstructed track momentum in the global system.
378
379 Double_t pt=TMath::Abs(GetPt()); // GeV/c
380 Double_t r=fC*fX-fE;
381
382 Double_t y0;
383 if(r > 1) { py = pt; px = 0; }
384 else if(r < -1) { py = -pt; px = 0; }
385 else {
386 y0=fY + sqrt(1.- r*r)/fC;
387 px=-pt*(fY-y0)*fC; //cos(phi);
388 py=-pt*(fE-fX*fC); //sin(phi);
389 }
390 pz=pt*fT;
391 Double_t tmp=px*TMath::Cos(fAlpha) - py*TMath::Sin(fAlpha);
392 py=px*TMath::Sin(fAlpha) + py*TMath::Cos(fAlpha);
393 px=tmp;
394
395}
396
397//_________________________________________________________________________
398void AliTOFtrack::GetGlobalXYZ(Double_t& x, Double_t& y, Double_t& z) const
399{
400 // Returns reconstructed track coordinates in the global system.
401
402 x = fX; y = fY; z = fZ;
403 Double_t tmp=x*TMath::Cos(fAlpha) - y*TMath::Sin(fAlpha);
404 y=x*TMath::Sin(fAlpha) + y*TMath::Cos(fAlpha);
405 x=tmp;
406
407}
408
409//_________________________________________________________________________
410void AliTOFtrack::ResetCovariance() {
411 //
412 // Resets covariance matrix
413 //
414
415 fCyy*=10.;
416 fCzy=0.; fCzz*=10.;
417 fCey=0.; fCez=0.; fCee*=10.;
418 fCty=0.; fCtz=0.; fCte=0.; fCtt*=10.;
419 fCcy=0.; fCcz=0.; fCce=0.; fCct=0.; fCcc*=10.;
420}
421
422
423//_________________________________________________________________________
424void AliTOFtrack::ResetCovariance(Float_t mult) {
425 //
426 // Resets covariance matrix
427 //
428
429 fCyy*=mult;
430 fCzy*=0.; fCzz*=mult;
431 fCey*=0.; fCez*=0.; fCee*=mult;
432 fCty*=0.; fCtz*=0.; fCte*=0.; fCtt*=mult;
433 fCcy*=0.; fCcz*=0.; fCce*=0.; fCct*=0.; fCcc*=mult;
434}
435
436//_____________________________________________________________________________
437Int_t AliTOFtrack::Compare(const TObject *o) const {
438 //-----------------------------------------------------------------
439 // This function compares tracks according to the their curvature
440 //-----------------------------------------------------------------
441 AliTOFtrack *t=(AliTOFtrack*)o;
442 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
443 Double_t c =GetSigmaY2()*GetSigmaZ2();
444 if (c>co) return 1;
445 else if (c<co) return -1;
446 return 0;
447}
448
449//_____________________________________________________________________________
450void AliTOFtrack::GetPropagationParameters(Bool_t holes, Double_t *param) {
451
2c770f53 452 //Get average medium density, x0 while propagating the track
453
454 //For TRD holes description
74ea065c 455
456 Double_t thetamin = (90.-31.1) * TMath::Pi()/180.;
457 Double_t thetamax = (90.+31.1) * TMath::Pi()/180.;
458
459 Double_t zmin = -55.;
460 Double_t zmax = 55.;
461
2c770f53 462 // Detector inner/outer radii
74ea065c 463 Double_t rTPC = 261.53;
464 Double_t rTPCTRD = 294.5;
465 Double_t rTRD = 369.1;
466
2c770f53 467 // Medium parameters
74ea065c 468 Double_t x0TPC = 40.;
469 Double_t rhoTPC =0.06124;
470
471 Double_t x0Air = 36.66;
472 Double_t rhoAir =1.2931e-3;
473
474 Double_t x0TRD = 171.7;
475 Double_t rhoTRD =0.33;
476
2c770f53 477 Int_t isec = GetSector();
74ea065c 478 Double_t xtr,ytr,ztr;
2c770f53 479 GetGlobalXYZ(xtr,ytr,ztr);
74ea065c 480 Float_t thetatr = TMath::ATan2(TMath::Sqrt(xtr*xtr+ytr*ytr),ztr);
481
482 if(holes){
483 if (isec == 0 || isec == 1 || isec == 2 ) {
484 if( thetatr>=thetamin && thetatr<=thetamax){
485 x0TRD= x0Air;
486 rhoTRD = rhoAir;
487 }
488 }
489 if (isec == 11 || isec == 12 || isec == 13 || isec == 14 || isec == 15 ) {
490 if( ztr>=zmin && ztr<=zmax){
491 x0TRD= x0Air;
492 rhoTRD = rhoAir;
493 }
494 }
495 }
496
2c770f53 497 if(GetX() <= rTPC)
74ea065c 498 {param[0]=x0TPC;param[1]=rhoTPC;}
2c770f53 499 else if(GetX() > rTPC && GetX() < rTPCTRD)
74ea065c 500 {param[0]=x0Air;param[1]=rhoAir;}
2c770f53 501 else if(GetX() >= rTPCTRD && GetX() < rTRD)
74ea065c 502 {param[0]=x0TRD;param[1]=rhoTRD;}
2c770f53 503 else if(GetX() >= rTRD )
74ea065c 504 {param[0]=x0Air;param[1]=rhoAir;}
74ea065c 505}