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a9e2aefa | 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 | $Log$ | |
94de3818 | 18 | Revision 1.7 2000/10/02 16:58:29 egangler |
19 | Cleaning of the code : | |
20 | -> coding conventions | |
21 | -> void Streamers | |
22 | -> some useless includes removed or replaced by "class" statement | |
23 | ||
ecfa008b | 24 | Revision 1.6 2000/09/19 09:49:50 gosset |
25 | AliMUONEventReconstructor package | |
26 | * track extrapolation independent from reco_muon.F, use of AliMagF... | |
27 | * possibility to use new magnetic field (automatic from generated root file) | |
28 | ||
a6f03ddb | 29 | Revision 1.5 2000/07/18 16:04:06 gosset |
30 | AliMUONEventReconstructor package: | |
31 | * a few minor modifications and more comments | |
32 | * a few corrections | |
33 | * right sign for Z of raw clusters | |
34 | * right loop over chambers inside station | |
35 | * symmetrized covariance matrix for measurements (TrackChi2MCS) | |
36 | * right sign of charge in extrapolation (ExtrapToZ) | |
37 | * right zEndAbsorber for Branson correction below 3 degrees | |
38 | * use of TVirtualFitter instead of TMinuit for AliMUONTrack::Fit | |
39 | * no parameter for AliMUONTrack::Fit() but more fit parameters in Track object | |
40 | ||
956019b6 | 41 | Revision 1.4 2000/07/03 07:53:31 morsch |
42 | Double declaration problem on HP solved. | |
43 | ||
88962f0c | 44 | Revision 1.3 2000/06/30 10:15:48 gosset |
45 | Changes to EventReconstructor...: | |
46 | precision fit with multiple Coulomb scattering; | |
47 | extrapolation to vertex with Branson correction in absorber (JPC) | |
48 | ||
04b5ea16 | 49 | Revision 1.2 2000/06/15 07:58:49 morsch |
50 | Code from MUON-dev joined | |
51 | ||
a9e2aefa | 52 | Revision 1.1.2.3 2000/06/09 21:03:09 morsch |
53 | Make includes consistent with new file structure. | |
54 | ||
55 | Revision 1.1.2.2 2000/06/09 12:58:05 gosset | |
56 | Removed comment beginnings in Log sections of .cxx files | |
57 | Suppressed most violations of coding rules | |
58 | ||
59 | Revision 1.1.2.1 2000/06/07 14:44:53 gosset | |
60 | Addition of files for track reconstruction in C++ | |
61 | */ | |
62 | ||
63 | //__________________________________________________________________________ | |
64 | // | |
65 | // Track parameters in ALICE dimuon spectrometer | |
66 | //__________________________________________________________________________ | |
67 | ||
68 | #include <iostream.h> | |
69 | ||
70 | #include "AliCallf77.h" | |
71 | #include "AliMUON.h" | |
72 | #include "AliMUONHitForRec.h" | |
73 | #include "AliMUONSegment.h" | |
74 | #include "AliMUONTrackParam.h" | |
75 | #include "AliMUONChamber.h" | |
76 | #include "AliRun.h" | |
94de3818 | 77 | #include "AliMagF.h" |
a9e2aefa | 78 | |
79 | ClassImp(AliMUONTrackParam) // Class implementation in ROOT context | |
80 | ||
a6f03ddb | 81 | // A few calls in Fortran or from Fortran (extrap.F). |
82 | // Needed, instead of calls to Geant subroutines, | |
83 | // because double precision is necessary for track fit converging with Minuit. | |
84 | // The "extrap" functions should be translated into C++ ???? | |
a9e2aefa | 85 | #ifndef WIN32 |
a6f03ddb | 86 | # define extrap_onestep_helix extrap_onestep_helix_ |
87 | # define extrap_onestep_helix3 extrap_onestep_helix3_ | |
88 | # define extrap_onestep_rungekutta extrap_onestep_rungekutta_ | |
89 | # define gufld_double gufld_double_ | |
a9e2aefa | 90 | #else |
a6f03ddb | 91 | # define extrap_onestep_helix EXTRAP_ONESTEP_HELIX |
92 | # define extrap_onestep_helix3 EXTRAP_ONESTEP_HELIX3 | |
93 | # define extrap_onestep_rungekutta EXTRAP_ONESTEP_RUNGEKUTTA | |
94 | # define gufld_double GUFLD_DOUBLE | |
a9e2aefa | 95 | #endif |
96 | ||
a6f03ddb | 97 | extern "C" { |
98 | void type_of_call extrap_onestep_helix | |
99 | (Double_t &Charge, Double_t &StepLength, Double_t *VGeant3, Double_t *VGeant3New); | |
100 | ||
101 | void type_of_call extrap_onestep_helix3 | |
102 | (Double_t &Field, Double_t &StepLength, Double_t *VGeant3, Double_t *VGeant3New); | |
103 | ||
104 | void type_of_call extrap_onestep_rungekutta | |
105 | (Double_t &Charge, Double_t &StepLength, Double_t *VGeant3, Double_t *VGeant3New); | |
106 | ||
107 | void type_of_call gufld_double(Double_t *Position, Double_t *Field) { | |
108 | // interface to "gAlice->Field()->Field" for arguments in double precision | |
109 | Float_t x[3], b[3]; | |
110 | x[0] = Position[0]; x[1] = Position[1]; x[2] = Position[2]; | |
111 | gAlice->Field()->Field(x, b); | |
112 | Field[0] = b[0]; Field[1] = b[1]; Field[2] = b[2]; | |
113 | } | |
a9e2aefa | 114 | } |
115 | ||
116 | // Inline functions for Get and Set: inline removed because it does not work !!!! | |
117 | Double_t AliMUONTrackParam::GetInverseBendingMomentum(void) { | |
118 | // Get fInverseBendingMomentum | |
119 | return fInverseBendingMomentum;} | |
120 | void AliMUONTrackParam::SetInverseBendingMomentum(Double_t InverseBendingMomentum) { | |
121 | // Set fInverseBendingMomentum | |
122 | fInverseBendingMomentum = InverseBendingMomentum;} | |
123 | Double_t AliMUONTrackParam::GetBendingSlope(void) { | |
124 | // Get fBendingSlope | |
125 | return fBendingSlope;} | |
126 | void AliMUONTrackParam::SetBendingSlope(Double_t BendingSlope) { | |
127 | // Set fBendingSlope | |
128 | fBendingSlope = BendingSlope;} | |
129 | Double_t AliMUONTrackParam::GetNonBendingSlope(void) { | |
130 | // Get fNonBendingSlope | |
131 | return fNonBendingSlope;} | |
132 | void AliMUONTrackParam::SetNonBendingSlope(Double_t NonBendingSlope) { | |
133 | // Set fNonBendingSlope | |
134 | fNonBendingSlope = NonBendingSlope;} | |
135 | Double_t AliMUONTrackParam::GetZ(void) { | |
136 | // Get fZ | |
137 | return fZ;} | |
138 | void AliMUONTrackParam::SetZ(Double_t Z) { | |
139 | // Set fZ | |
140 | fZ = Z;} | |
141 | Double_t AliMUONTrackParam::GetBendingCoor(void) { | |
142 | // Get fBendingCoor | |
143 | return fBendingCoor;} | |
144 | void AliMUONTrackParam::SetBendingCoor(Double_t BendingCoor) { | |
145 | // Set fBendingCoor | |
146 | fBendingCoor = BendingCoor;} | |
147 | Double_t AliMUONTrackParam::GetNonBendingCoor(void) { | |
148 | // Get fNonBendingCoor | |
149 | return fNonBendingCoor;} | |
150 | void AliMUONTrackParam::SetNonBendingCoor(Double_t NonBendingCoor) { | |
151 | // Set fNonBendingCoor | |
152 | fNonBendingCoor = NonBendingCoor;} | |
153 | ||
154 | //__________________________________________________________________________ | |
155 | void AliMUONTrackParam::ExtrapToZ(Double_t Z) | |
156 | { | |
157 | // Track parameter extrapolation to the plane at "Z". | |
158 | // On return, the track parameters resulting from the extrapolation | |
159 | // replace the current track parameters. | |
a9e2aefa | 160 | if (this->fZ == Z) return; // nothing to be done if same Z |
161 | Double_t forwardBackward; // +1 if forward, -1 if backward | |
162 | if (Z > this->fZ) forwardBackward = 1.0; | |
163 | else forwardBackward = -1.0; | |
a6f03ddb | 164 | Double_t vGeant3[7], vGeant3New[7]; // 7 in parameter ???? |
a9e2aefa | 165 | Int_t iGeant3, stepNumber; |
166 | Int_t maxStepNumber = 5000; // in parameter ???? | |
167 | // For safety: return kTRUE or kFALSE ???? | |
a6f03ddb | 168 | // Parameter vector for calling EXTRAP_ONESTEP |
a9e2aefa | 169 | SetGeant3Parameters(vGeant3, forwardBackward); |
956019b6 | 170 | // sign of charge (sign of fInverseBendingMomentum if forward motion) |
a6f03ddb | 171 | // must be changed if backward extrapolation |
956019b6 | 172 | Double_t chargeExtrap = forwardBackward * |
173 | TMath::Sign(Double_t(1.0), this->fInverseBendingMomentum); | |
a9e2aefa | 174 | Double_t stepLength = 6.0; // in parameter ???? |
175 | // Extrapolation loop | |
176 | stepNumber = 0; | |
177 | while (((forwardBackward * (vGeant3[2] - Z)) <= 0.0) && | |
178 | (stepNumber < maxStepNumber)) { | |
179 | stepNumber++; | |
a6f03ddb | 180 | // Option for switching between helix and Runge-Kutta ???? |
181 | // extrap_onestep_rungekutta(chargeExtrap, stepLength, vGeant3, vGeant3New); | |
182 | extrap_onestep_helix(chargeExtrap, stepLength, vGeant3, vGeant3New); | |
a9e2aefa | 183 | if ((forwardBackward * (vGeant3New[2] - Z)) > 0.0) break; // one is beyond Z |
184 | // better use TArray ???? | |
185 | for (iGeant3 = 0; iGeant3 < 7; iGeant3++) | |
186 | {vGeant3[iGeant3] = vGeant3New[iGeant3];} | |
187 | } | |
188 | // check maxStepNumber ???? | |
a9e2aefa | 189 | // Interpolation back to exact Z (2nd order) |
190 | // should be in function ???? using TArray ???? | |
191 | Double_t dZ12 = vGeant3New[2] - vGeant3[2]; // 1->2 | |
192 | Double_t dZ1i = Z - vGeant3[2]; // 1-i | |
193 | Double_t dZi2 = vGeant3New[2] - Z; // i->2 | |
194 | Double_t xPrime = (vGeant3New[0] - vGeant3[0]) / dZ12; | |
195 | Double_t xSecond = | |
196 | ((vGeant3New[3] / vGeant3New[5]) - (vGeant3[3] / vGeant3[5])) / dZ12; | |
197 | Double_t yPrime = (vGeant3New[1] - vGeant3[1]) / dZ12; | |
198 | Double_t ySecond = | |
199 | ((vGeant3New[4] / vGeant3New[5]) - (vGeant3[4] / vGeant3[5])) / dZ12; | |
200 | vGeant3[0] = vGeant3[0] + xPrime * dZ1i - 0.5 * xSecond * dZ1i * dZi2; // X | |
201 | vGeant3[1] = vGeant3[1] + yPrime * dZ1i - 0.5 * ySecond * dZ1i * dZi2; // Y | |
202 | vGeant3[2] = Z; // Z | |
203 | Double_t xPrimeI = xPrime - 0.5 * xSecond * (dZi2 - dZ1i); | |
204 | Double_t yPrimeI = yPrime - 0.5 * ySecond * (dZi2 - dZ1i); | |
956019b6 | 205 | // (PX, PY, PZ)/PTOT assuming forward motion |
a9e2aefa | 206 | vGeant3[5] = |
207 | 1.0 / TMath::Sqrt(1.0 + xPrimeI * xPrimeI + yPrimeI * yPrimeI); // PZ/PTOT | |
208 | vGeant3[3] = xPrimeI * vGeant3[5]; // PX/PTOT | |
209 | vGeant3[4] = yPrimeI * vGeant3[5]; // PY/PTOT | |
956019b6 | 210 | // Track parameters from Geant3 parameters, |
211 | // with charge back for forward motion | |
212 | GetFromGeant3Parameters(vGeant3, chargeExtrap * forwardBackward); | |
a9e2aefa | 213 | } |
214 | ||
215 | //__________________________________________________________________________ | |
216 | void AliMUONTrackParam::SetGeant3Parameters(Double_t *VGeant3, Double_t ForwardBackward) | |
217 | { | |
218 | // Set vector of Geant3 parameters pointed to by "VGeant3" | |
219 | // from track parameters in current AliMUONTrackParam. | |
220 | // Since AliMUONTrackParam is only geometry, one uses "ForwardBackward" | |
221 | // to know whether the particle is going forward (+1) or backward (-1). | |
222 | VGeant3[0] = this->fNonBendingCoor; // X | |
223 | VGeant3[1] = this->fBendingCoor; // Y | |
224 | VGeant3[2] = this->fZ; // Z | |
225 | Double_t pYZ = TMath::Abs(1.0 / this->fInverseBendingMomentum); | |
226 | Double_t pZ = | |
227 | pYZ / TMath::Sqrt(1.0 + this->fBendingSlope * this->fBendingSlope); | |
228 | VGeant3[6] = | |
229 | TMath::Sqrt(pYZ * pYZ + | |
230 | pZ * pZ * this->fNonBendingSlope * this->fNonBendingSlope); // PTOT | |
231 | VGeant3[5] = ForwardBackward * pZ / VGeant3[6]; // PZ/PTOT | |
232 | VGeant3[3] = this->fNonBendingSlope * VGeant3[5]; // PX/PTOT | |
233 | VGeant3[4] = this->fBendingSlope * VGeant3[5]; // PY/PTOT | |
234 | } | |
235 | ||
236 | //__________________________________________________________________________ | |
237 | void AliMUONTrackParam::GetFromGeant3Parameters(Double_t *VGeant3, Double_t Charge) | |
238 | { | |
239 | // Get track parameters in current AliMUONTrackParam | |
956019b6 | 240 | // from Geant3 parameters pointed to by "VGeant3", |
241 | // assumed to be calculated for forward motion in Z. | |
a9e2aefa | 242 | // "InverseBendingMomentum" is signed with "Charge". |
243 | this->fNonBendingCoor = VGeant3[0]; // X | |
244 | this->fBendingCoor = VGeant3[1]; // Y | |
245 | this->fZ = VGeant3[2]; // Z | |
246 | Double_t pYZ = VGeant3[6] * TMath::Sqrt(1.0 - VGeant3[3] * VGeant3[3]); | |
247 | this->fInverseBendingMomentum = Charge / pYZ; | |
248 | this->fBendingSlope = VGeant3[4] / VGeant3[5]; | |
249 | this->fNonBendingSlope = VGeant3[3] / VGeant3[5]; | |
250 | } | |
251 | ||
252 | //__________________________________________________________________________ | |
253 | void AliMUONTrackParam::ExtrapToStation(Int_t Station, AliMUONTrackParam *TrackParam) | |
254 | { | |
255 | // Track parameters extrapolated from current track parameters ("this") | |
256 | // to both chambers of the station(0..) "Station" | |
257 | // are returned in the array (dimension 2) of track parameters | |
258 | // pointed to by "TrackParam" (index 0 and 1 for first and second chambers). | |
259 | Double_t extZ[2], z1, z2; | |
ecfa008b | 260 | Int_t i1 = -1, i2 = -1; // = -1 to avoid compilation warnings |
a9e2aefa | 261 | AliMUON *pMUON = (AliMUON*) gAlice->GetModule("MUON"); // necessary ???? |
262 | // range of Station to be checked ???? | |
263 | z1 = (&(pMUON->Chamber(2 * Station)))->Z(); // Z of first chamber | |
264 | z2 = (&(pMUON->Chamber(2 * Station + 1)))->Z(); // Z of second chamber | |
265 | // First and second Z to extrapolate at | |
266 | if ((z1 > this->fZ) && (z2 > this->fZ)) {i1 = 0; i2 = 1;} | |
267 | else if ((z1 < this->fZ) && (z2 < this->fZ)) {i1 = 1; i2 = 0;} | |
268 | else { | |
269 | cout << "ERROR in AliMUONTrackParam::CreateExtrapSegmentInStation" << endl; | |
270 | cout << "Starting Z (" << this->fZ << ") in between z1 (" << z1 << | |
271 | ") and z2 (" << z2 << ") of station(0..) " << Station << endl; | |
272 | } | |
273 | extZ[i1] = z1; | |
274 | extZ[i2] = z2; | |
275 | // copy of track parameters | |
276 | TrackParam[i1] = *this; | |
277 | // first extrapolation | |
278 | (&(TrackParam[i1]))->ExtrapToZ(extZ[0]); | |
279 | TrackParam[i2] = TrackParam[i1]; | |
280 | // second extrapolation | |
281 | (&(TrackParam[i2]))->ExtrapToZ(extZ[1]); | |
282 | return; | |
283 | } | |
284 | ||
04b5ea16 | 285 | //__________________________________________________________________________ |
286 | void AliMUONTrackParam::ExtrapToVertex() | |
287 | { | |
288 | // Extrapolation to the vertex. | |
289 | // Returns the track parameters resulting from the extrapolation, | |
290 | // in the current TrackParam. | |
956019b6 | 291 | // Changes parameters according to Branson correction through the absorber |
04b5ea16 | 292 | |
293 | Double_t zAbsorber = 503.0; // to be coherent with the Geant absorber geometry !!!! | |
294 | // Extrapolates track parameters upstream to the "Z" end of the front absorber | |
295 | ExtrapToZ(zAbsorber); | |
296 | // Makes Branson correction (multiple scattering + energy loss) | |
297 | BransonCorrection(); | |
298 | } | |
299 | ||
300 | //__________________________________________________________________________ | |
301 | void AliMUONTrackParam::BransonCorrection() | |
302 | { | |
303 | // Branson correction of track parameters | |
304 | // the entry parameters have to be calculated at the end of the absorber | |
305 | Double_t zEndAbsorber, zBP, xBP, yBP; | |
306 | Double_t pYZ, pX, pY, pZ, pTotal, xEndAbsorber, yEndAbsorber, radiusEndAbsorber2, pT, theta; | |
307 | Int_t sign; | |
308 | // Would it be possible to calculate all that from Geant configuration ???? | |
956019b6 | 309 | // and to get the Branson parameters from a function in ABSO module ???? |
310 | // with an eventual contribution from other detectors like START ???? | |
04b5ea16 | 311 | // Radiation lengths outer part theta > 3 degres |
312 | static Double_t x01[9] = { 18.8, // C (cm) | |
313 | 10.397, // Concrete (cm) | |
314 | 0.56, // Plomb (cm) | |
315 | 47.26, // Polyethylene (cm) | |
316 | 0.56, // Plomb (cm) | |
317 | 47.26, // Polyethylene (cm) | |
318 | 0.56, // Plomb (cm) | |
319 | 47.26, // Polyethylene (cm) | |
320 | 0.56 }; // Plomb (cm) | |
321 | // inner part theta < 3 degres | |
322 | static Double_t x02[3] = { 18.8, // C (cm) | |
323 | 10.397, // Concrete (cm) | |
324 | 0.35 }; // W (cm) | |
325 | // z positions of the materials inside the absober outer part theta > 3 degres | |
326 | static Double_t z1[10] = { 90, 315, 467, 472, 477, 482, 487, 492, 497, 502 }; | |
327 | // inner part theta < 3 degres | |
328 | static Double_t z2[4] = { 90, 315, 467, 503 }; | |
329 | static Bool_t first = kTRUE; | |
330 | static Double_t zBP1, zBP2, rLimit; | |
331 | // Calculates z positions of the Branson's planes: zBP1 for outer part and zBP2 for inner part (only at the first call) | |
332 | if (first) { | |
333 | first = kFALSE; | |
334 | Double_t aNBP = 0.0; | |
335 | Double_t aDBP = 0.0; | |
88962f0c | 336 | Int_t iBound; |
337 | ||
338 | for (iBound = 0; iBound < 9; iBound++) { | |
04b5ea16 | 339 | aNBP = aNBP + |
340 | (z1[iBound+1] * z1[iBound+1] * z1[iBound+1] - | |
341 | z1[iBound] * z1[iBound] * z1[iBound] ) / x01[iBound]; | |
342 | aDBP = aDBP + | |
343 | (z1[iBound+1] * z1[iBound+1] - z1[iBound] * z1[iBound] ) / x01[iBound]; | |
344 | } | |
345 | zBP1 = (2.0 * aNBP) / (3.0 * aDBP); | |
346 | aNBP = 0.0; | |
347 | aDBP = 0.0; | |
88962f0c | 348 | for (iBound = 0; iBound < 3; iBound++) { |
04b5ea16 | 349 | aNBP = aNBP + |
350 | (z2[iBound+1] * z2[iBound+1] * z2[iBound+1] - | |
351 | z2[iBound] * z2[iBound ] * z2[iBound] ) / x02[iBound]; | |
352 | aDBP = aDBP + | |
353 | (z2[iBound+1] * z2[iBound+1] - z2[iBound] * z2[iBound]) / x02[iBound]; | |
354 | } | |
355 | zBP2 = (2.0 * aNBP) / (3.0 * aDBP); | |
356 | rLimit = z2[3] * TMath::Tan(3.0 * (TMath::Pi()) / 180.); | |
357 | } | |
358 | ||
359 | pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); | |
360 | sign = 1; | |
361 | if (fInverseBendingMomentum < 0) sign = -1; | |
362 | pZ = pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); | |
363 | pX = pZ * fNonBendingSlope; | |
364 | pY = pZ * fBendingSlope; | |
365 | pTotal = TMath::Sqrt(pYZ *pYZ + pX * pX); | |
366 | xEndAbsorber = fNonBendingCoor; | |
367 | yEndAbsorber = fBendingCoor; | |
368 | radiusEndAbsorber2 = xEndAbsorber * xEndAbsorber + yEndAbsorber * yEndAbsorber; | |
369 | ||
370 | if (radiusEndAbsorber2 > rLimit*rLimit) { | |
371 | zEndAbsorber = z1[9]; | |
372 | zBP = zBP1; | |
373 | } else { | |
956019b6 | 374 | zEndAbsorber = z2[3]; |
04b5ea16 | 375 | zBP = zBP2; |
376 | } | |
377 | ||
378 | xBP = xEndAbsorber - (pX / pZ) * (zEndAbsorber - zBP); | |
379 | yBP = yEndAbsorber - (pY / pZ) * (zEndAbsorber - zBP); | |
380 | ||
381 | // new parameters after Branson and energy loss corrections | |
382 | pZ = pTotal * zBP / TMath::Sqrt(xBP * xBP + yBP * yBP + zBP * zBP); | |
383 | pX = pZ * xBP / zBP; | |
384 | pY = pZ * yBP / zBP; | |
385 | fBendingSlope = pY / pZ; | |
386 | fNonBendingSlope = pX / pZ; | |
387 | ||
388 | pT = TMath::Sqrt(pX * pX + pY * pY); | |
389 | theta = TMath::ATan2(pT, pZ); | |
390 | pTotal = | |
391 | TotalMomentumEnergyLoss(rLimit, pTotal, theta, xEndAbsorber, yEndAbsorber); | |
392 | ||
393 | fInverseBendingMomentum = (sign / pTotal) * | |
394 | TMath::Sqrt(1.0 + | |
395 | fBendingSlope * fBendingSlope + | |
396 | fNonBendingSlope * fNonBendingSlope) / | |
397 | TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope); | |
398 | ||
399 | // vertex position at (0,0,0) | |
400 | // should be taken from vertex measurement ??? | |
401 | fBendingCoor = 0.0; | |
402 | fNonBendingCoor = 0; | |
403 | fZ= 0; | |
404 | } | |
405 | ||
406 | //__________________________________________________________________________ | |
407 | Double_t AliMUONTrackParam::TotalMomentumEnergyLoss(Double_t rLimit, Double_t pTotal, Double_t theta, Double_t xEndAbsorber, Double_t yEndAbsorber) | |
408 | { | |
409 | // Returns the total momentum corrected from energy loss in the front absorber | |
410 | Double_t deltaP, pTotalCorrected; | |
411 | ||
412 | Double_t radiusEndAbsorber2 = | |
413 | xEndAbsorber *xEndAbsorber + yEndAbsorber * yEndAbsorber; | |
414 | // Parametrization to be redone according to change of absorber material ???? | |
956019b6 | 415 | // See remark in function BransonCorrection !!!! |
04b5ea16 | 416 | // The name is not so good, and there are many arguments !!!! |
417 | if (radiusEndAbsorber2 < rLimit * rLimit) { | |
418 | if (pTotal < 15) { | |
419 | deltaP = 2.737 + 0.0494 * pTotal - 0.001123 * pTotal * pTotal; | |
420 | } else { | |
421 | deltaP = 3.0643 + 0.01346 *pTotal; | |
422 | } | |
423 | } else { | |
424 | if (pTotal < 15) { | |
425 | deltaP = 2.1380 + 0.0351 * pTotal - 0.000853 * pTotal * pTotal; | |
426 | } else { | |
427 | deltaP = 2.407 + 0.00702 * pTotal; | |
428 | } | |
429 | } | |
430 | pTotalCorrected = pTotal + deltaP / TMath::Cos(theta); | |
431 | return pTotalCorrected; | |
432 | } | |
433 |