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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 | ||
88cb7938 | 16 | /* $Id$ */ |
a9e2aefa | 17 | |
3831f268 | 18 | /////////////////////////////////////////////////// |
19 | // | |
20 | // Track parameters | |
21 | // in | |
22 | // ALICE | |
23 | // dimuon | |
24 | // spectrometer | |
a9e2aefa | 25 | // |
3831f268 | 26 | /////////////////////////////////////////////////// |
a9e2aefa | 27 | |
58443fe3 | 28 | //#include <Riostream.h> |
3831f268 | 29 | #include "AliMUON.h" |
a9e2aefa | 30 | #include "AliMUONTrackParam.h" |
06c11448 | 31 | #include "AliMUONConstants.h" |
211c52eb | 32 | #include "AliESDMuonTrack.h" |
94de3818 | 33 | #include "AliMagF.h" |
8c343c7c | 34 | #include "AliLog.h" |
1a38e749 | 35 | #include "AliTracker.h" |
de2cd600 | 36 | #include "AliMUONHitForRec.h" |
a9e2aefa | 37 | |
38 | ClassImp(AliMUONTrackParam) // Class implementation in ROOT context | |
39 | ||
61adb9bd | 40 | //_________________________________________________________________________ |
30178c30 | 41 | AliMUONTrackParam::AliMUONTrackParam() |
54d7ba50 | 42 | : TObject(), |
43 | fInverseBendingMomentum(0.), | |
44 | fBendingSlope(0.), | |
45 | fNonBendingSlope(0.), | |
46 | fZ(0.), | |
47 | fBendingCoor(0.), | |
de2cd600 | 48 | fNonBendingCoor(0.), |
49 | fkField(0x0), | |
50 | fHitForRecPtr(0x0) | |
30178c30 | 51 | { |
52 | // Constructor | |
1a38e749 | 53 | // get field from outside |
54 | fkField = AliTracker::GetFieldMap(); | |
d13a4ed5 | 55 | if (!fkField) AliWarning("No field available"); |
30178c30 | 56 | } |
61adb9bd | 57 | |
30178c30 | 58 | //_________________________________________________________________________ |
de2cd600 | 59 | AliMUONTrackParam::AliMUONTrackParam(const AliMUONTrackParam& theMUONTrackParam) |
60 | : TObject(theMUONTrackParam), | |
61 | fInverseBendingMomentum(theMUONTrackParam.fInverseBendingMomentum), | |
62 | fBendingSlope(theMUONTrackParam.fBendingSlope), | |
63 | fNonBendingSlope(theMUONTrackParam.fNonBendingSlope), | |
64 | fZ(theMUONTrackParam.fZ), | |
65 | fBendingCoor(theMUONTrackParam.fBendingCoor), | |
66 | fNonBendingCoor(theMUONTrackParam.fNonBendingCoor), | |
67 | fkField(theMUONTrackParam.fkField), | |
68 | fHitForRecPtr(theMUONTrackParam.fHitForRecPtr) | |
69 | { | |
70 | // Copy constructor | |
71 | ||
72 | } | |
73 | ||
74 | //_________________________________________________________________________ | |
75 | AliMUONTrackParam& AliMUONTrackParam::operator=(const AliMUONTrackParam& theMUONTrackParam) | |
61adb9bd | 76 | { |
58443fe3 | 77 | // Asignment operator |
30178c30 | 78 | if (this == &theMUONTrackParam) |
61adb9bd | 79 | return *this; |
80 | ||
30178c30 | 81 | // base class assignement |
82 | TObject::operator=(theMUONTrackParam); | |
83 | ||
84 | fInverseBendingMomentum = theMUONTrackParam.fInverseBendingMomentum; | |
85 | fBendingSlope = theMUONTrackParam.fBendingSlope; | |
86 | fNonBendingSlope = theMUONTrackParam.fNonBendingSlope; | |
87 | fZ = theMUONTrackParam.fZ; | |
88 | fBendingCoor = theMUONTrackParam.fBendingCoor; | |
89 | fNonBendingCoor = theMUONTrackParam.fNonBendingCoor; | |
de2cd600 | 90 | fkField = theMUONTrackParam.fkField; |
91 | fHitForRecPtr = theMUONTrackParam.fHitForRecPtr; | |
61adb9bd | 92 | |
93 | return *this; | |
94 | } | |
de2cd600 | 95 | |
96 | //__________________________________________________________________________ | |
97 | AliMUONTrackParam::~AliMUONTrackParam() | |
61adb9bd | 98 | { |
de2cd600 | 99 | /// Destructor |
100 | /// Update the number of TrackHit's connected to the attached HitForRec if any | |
101 | if (fHitForRecPtr) fHitForRecPtr->SetNTrackHits(fHitForRecPtr->GetNTrackHits() - 1); // decrement NTrackHits of hit | |
102 | } | |
103 | ||
104 | //__________________________________________________________________________ | |
105 | void AliMUONTrackParam::SetTrackParam(AliMUONTrackParam& theMUONTrackParam) | |
106 | { | |
107 | /// Set track parameters from "TrackParam" leaving pointer to fHitForRecPtr unchanged | |
108 | fInverseBendingMomentum = theMUONTrackParam.fInverseBendingMomentum; | |
109 | fBendingSlope = theMUONTrackParam.fBendingSlope; | |
110 | fNonBendingSlope = theMUONTrackParam.fNonBendingSlope; | |
111 | fZ = theMUONTrackParam.fZ; | |
112 | fBendingCoor = theMUONTrackParam.fBendingCoor; | |
113 | fNonBendingCoor = theMUONTrackParam.fNonBendingCoor; | |
114 | ||
115 | } | |
54d7ba50 | 116 | |
de2cd600 | 117 | //__________________________________________________________________________ |
118 | AliMUONHitForRec* AliMUONTrackParam::GetHitForRecPtr(void) const | |
119 | { | |
120 | /// return pointer to HitForRec attached to the current TrackParam | |
121 | /// this method should not be called when fHitForRecPtr == NULL | |
122 | if (!fHitForRecPtr) AliWarning("AliMUONTrackParam::GetHitForRecPtr: fHitForRecPtr == NULL"); | |
123 | return fHitForRecPtr; | |
124 | } | |
125 | ||
126 | //__________________________________________________________________________ | |
127 | Int_t AliMUONTrackParam::Compare(const TObject* TrackParam) const | |
128 | { | |
129 | /// "Compare" function to sort with decreasing Z (spectro. muon Z <0). | |
130 | /// Returns 1 (0, -1) if Z of current TrackHit | |
131 | /// is smaller than (equal to, larger than) Z of TrackHit | |
132 | if (fHitForRecPtr->GetZ() < ((AliMUONTrackParam*)TrackParam)->fHitForRecPtr->GetZ()) return(1); | |
133 | else if (fHitForRecPtr->GetZ() == ((AliMUONTrackParam*)TrackParam)->fHitForRecPtr->GetZ()) return(0); | |
134 | else return(-1); | |
61adb9bd | 135 | } |
a9e2aefa | 136 | |
211c52eb | 137 | //_________________________________________________________________________ |
138 | void AliMUONTrackParam::GetParamFrom(const AliESDMuonTrack& esdMuonTrack) | |
139 | { | |
140 | // assigned value form ESD track. | |
141 | fInverseBendingMomentum = esdMuonTrack.GetInverseBendingMomentum(); | |
142 | fBendingSlope = TMath::Tan(esdMuonTrack.GetThetaY()); | |
143 | fNonBendingSlope = TMath::Tan(esdMuonTrack.GetThetaX()); | |
144 | fZ = esdMuonTrack.GetZ(); | |
145 | fBendingCoor = esdMuonTrack.GetBendingCoor(); | |
146 | fNonBendingCoor = esdMuonTrack.GetNonBendingCoor(); | |
147 | } | |
148 | ||
149 | //_________________________________________________________________________ | |
150 | void AliMUONTrackParam::SetParamFor(AliESDMuonTrack& esdMuonTrack) | |
151 | { | |
152 | // assigned value form ESD track. | |
153 | esdMuonTrack.SetInverseBendingMomentum(fInverseBendingMomentum); | |
154 | esdMuonTrack.SetThetaX(TMath::ATan(fNonBendingSlope)); | |
155 | esdMuonTrack.SetThetaY(TMath::ATan(fBendingSlope)); | |
156 | esdMuonTrack.SetZ(fZ); | |
157 | esdMuonTrack.SetBendingCoor(fBendingCoor); | |
158 | esdMuonTrack.SetNonBendingCoor(fNonBendingCoor); | |
159 | } | |
160 | ||
a9e2aefa | 161 | //__________________________________________________________________________ |
162 | void AliMUONTrackParam::ExtrapToZ(Double_t Z) | |
163 | { | |
164 | // Track parameter extrapolation to the plane at "Z". | |
165 | // On return, the track parameters resulting from the extrapolation | |
166 | // replace the current track parameters. | |
a9e2aefa | 167 | if (this->fZ == Z) return; // nothing to be done if same Z |
168 | Double_t forwardBackward; // +1 if forward, -1 if backward | |
5b64e914 | 169 | if (Z < this->fZ) forwardBackward = 1.0; // spectro. z<0 |
a9e2aefa | 170 | else forwardBackward = -1.0; |
a6f03ddb | 171 | Double_t vGeant3[7], vGeant3New[7]; // 7 in parameter ???? |
a9e2aefa | 172 | Int_t iGeant3, stepNumber; |
173 | Int_t maxStepNumber = 5000; // in parameter ???? | |
174 | // For safety: return kTRUE or kFALSE ???? | |
a6f03ddb | 175 | // Parameter vector for calling EXTRAP_ONESTEP |
a9e2aefa | 176 | SetGeant3Parameters(vGeant3, forwardBackward); |
956019b6 | 177 | // sign of charge (sign of fInverseBendingMomentum if forward motion) |
a6f03ddb | 178 | // must be changed if backward extrapolation |
956019b6 | 179 | Double_t chargeExtrap = forwardBackward * |
180 | TMath::Sign(Double_t(1.0), this->fInverseBendingMomentum); | |
a9e2aefa | 181 | Double_t stepLength = 6.0; // in parameter ???? |
182 | // Extrapolation loop | |
183 | stepNumber = 0; | |
5b64e914 | 184 | while (((-forwardBackward * (vGeant3[2] - Z)) <= 0.0) && // spectro. z<0 |
a9e2aefa | 185 | (stepNumber < maxStepNumber)) { |
186 | stepNumber++; | |
a6f03ddb | 187 | // Option for switching between helix and Runge-Kutta ???? |
4d03a78e | 188 | //ExtrapOneStepRungekutta(chargeExtrap, stepLength, vGeant3, vGeant3New); |
189 | ExtrapOneStepHelix(chargeExtrap, stepLength, vGeant3, vGeant3New); | |
5b64e914 | 190 | if ((-forwardBackward * (vGeant3New[2] - Z)) > 0.0) break; // one is beyond Z spectro. z<0 |
a9e2aefa | 191 | // better use TArray ???? |
192 | for (iGeant3 = 0; iGeant3 < 7; iGeant3++) | |
193 | {vGeant3[iGeant3] = vGeant3New[iGeant3];} | |
194 | } | |
195 | // check maxStepNumber ???? | |
a9e2aefa | 196 | // Interpolation back to exact Z (2nd order) |
197 | // should be in function ???? using TArray ???? | |
198 | Double_t dZ12 = vGeant3New[2] - vGeant3[2]; // 1->2 | |
1e2b8bb7 | 199 | if (TMath::Abs(dZ12) > 0) { |
200 | Double_t dZ1i = Z - vGeant3[2]; // 1-i | |
201 | Double_t dZi2 = vGeant3New[2] - Z; // i->2 | |
202 | Double_t xPrime = (vGeant3New[0] - vGeant3[0]) / dZ12; | |
203 | Double_t xSecond = | |
204 | ((vGeant3New[3] / vGeant3New[5]) - (vGeant3[3] / vGeant3[5])) / dZ12; | |
205 | Double_t yPrime = (vGeant3New[1] - vGeant3[1]) / dZ12; | |
206 | Double_t ySecond = | |
207 | ((vGeant3New[4] / vGeant3New[5]) - (vGeant3[4] / vGeant3[5])) / dZ12; | |
208 | vGeant3[0] = vGeant3[0] + xPrime * dZ1i - 0.5 * xSecond * dZ1i * dZi2; // X | |
209 | vGeant3[1] = vGeant3[1] + yPrime * dZ1i - 0.5 * ySecond * dZ1i * dZi2; // Y | |
210 | vGeant3[2] = Z; // Z | |
211 | Double_t xPrimeI = xPrime - 0.5 * xSecond * (dZi2 - dZ1i); | |
212 | Double_t yPrimeI = yPrime - 0.5 * ySecond * (dZi2 - dZ1i); | |
213 | // (PX, PY, PZ)/PTOT assuming forward motion | |
214 | vGeant3[5] = | |
215 | 1.0 / TMath::Sqrt(1.0 + xPrimeI * xPrimeI + yPrimeI * yPrimeI); // PZ/PTOT | |
216 | vGeant3[3] = xPrimeI * vGeant3[5]; // PX/PTOT | |
217 | vGeant3[4] = yPrimeI * vGeant3[5]; // PY/PTOT | |
218 | } else { | |
219 | AliWarning(Form("Extrap. to Z not reached, Z = %f",Z)); | |
220 | } | |
956019b6 | 221 | // Track parameters from Geant3 parameters, |
222 | // with charge back for forward motion | |
223 | GetFromGeant3Parameters(vGeant3, chargeExtrap * forwardBackward); | |
a9e2aefa | 224 | } |
225 | ||
226 | //__________________________________________________________________________ | |
227 | void AliMUONTrackParam::SetGeant3Parameters(Double_t *VGeant3, Double_t ForwardBackward) | |
228 | { | |
229 | // Set vector of Geant3 parameters pointed to by "VGeant3" | |
230 | // from track parameters in current AliMUONTrackParam. | |
231 | // Since AliMUONTrackParam is only geometry, one uses "ForwardBackward" | |
232 | // to know whether the particle is going forward (+1) or backward (-1). | |
233 | VGeant3[0] = this->fNonBendingCoor; // X | |
234 | VGeant3[1] = this->fBendingCoor; // Y | |
235 | VGeant3[2] = this->fZ; // Z | |
236 | Double_t pYZ = TMath::Abs(1.0 / this->fInverseBendingMomentum); | |
237 | Double_t pZ = | |
238 | pYZ / TMath::Sqrt(1.0 + this->fBendingSlope * this->fBendingSlope); | |
239 | VGeant3[6] = | |
240 | TMath::Sqrt(pYZ * pYZ + | |
241 | pZ * pZ * this->fNonBendingSlope * this->fNonBendingSlope); // PTOT | |
5b64e914 | 242 | VGeant3[5] = -ForwardBackward * pZ / VGeant3[6]; // PZ/PTOT spectro. z<0 |
a9e2aefa | 243 | VGeant3[3] = this->fNonBendingSlope * VGeant3[5]; // PX/PTOT |
244 | VGeant3[4] = this->fBendingSlope * VGeant3[5]; // PY/PTOT | |
245 | } | |
246 | ||
247 | //__________________________________________________________________________ | |
248 | void AliMUONTrackParam::GetFromGeant3Parameters(Double_t *VGeant3, Double_t Charge) | |
249 | { | |
250 | // Get track parameters in current AliMUONTrackParam | |
956019b6 | 251 | // from Geant3 parameters pointed to by "VGeant3", |
252 | // assumed to be calculated for forward motion in Z. | |
a9e2aefa | 253 | // "InverseBendingMomentum" is signed with "Charge". |
254 | this->fNonBendingCoor = VGeant3[0]; // X | |
255 | this->fBendingCoor = VGeant3[1]; // Y | |
256 | this->fZ = VGeant3[2]; // Z | |
257 | Double_t pYZ = VGeant3[6] * TMath::Sqrt(1.0 - VGeant3[3] * VGeant3[3]); | |
258 | this->fInverseBendingMomentum = Charge / pYZ; | |
259 | this->fBendingSlope = VGeant3[4] / VGeant3[5]; | |
260 | this->fNonBendingSlope = VGeant3[3] / VGeant3[5]; | |
261 | } | |
262 | ||
263 | //__________________________________________________________________________ | |
264 | void AliMUONTrackParam::ExtrapToStation(Int_t Station, AliMUONTrackParam *TrackParam) | |
265 | { | |
266 | // Track parameters extrapolated from current track parameters ("this") | |
267 | // to both chambers of the station(0..) "Station" | |
268 | // are returned in the array (dimension 2) of track parameters | |
269 | // pointed to by "TrackParam" (index 0 and 1 for first and second chambers). | |
270 | Double_t extZ[2], z1, z2; | |
ecfa008b | 271 | Int_t i1 = -1, i2 = -1; // = -1 to avoid compilation warnings |
a9e2aefa | 272 | // range of Station to be checked ???? |
06c11448 | 273 | z1 = AliMUONConstants::DefaultChamberZ(2 * Station); |
274 | z2 = AliMUONConstants::DefaultChamberZ(2 * Station + 1); | |
a9e2aefa | 275 | // First and second Z to extrapolate at |
276 | if ((z1 > this->fZ) && (z2 > this->fZ)) {i1 = 0; i2 = 1;} | |
277 | else if ((z1 < this->fZ) && (z2 < this->fZ)) {i1 = 1; i2 = 0;} | |
278 | else { | |
8c343c7c | 279 | AliError(Form("Starting Z (%f) in between z1 (%f) and z2 (%f) of station(0..)%d",this->fZ,z1,z2,Station)); |
280 | // cout << "ERROR in AliMUONTrackParam::CreateExtrapSegmentInStation" << endl; | |
281 | // cout << "Starting Z (" << this->fZ << ") in between z1 (" << z1 << | |
282 | // ") and z2 (" << z2 << ") of station(0..) " << Station << endl; | |
a9e2aefa | 283 | } |
284 | extZ[i1] = z1; | |
285 | extZ[i2] = z2; | |
286 | // copy of track parameters | |
287 | TrackParam[i1] = *this; | |
288 | // first extrapolation | |
289 | (&(TrackParam[i1]))->ExtrapToZ(extZ[0]); | |
290 | TrackParam[i2] = TrackParam[i1]; | |
291 | // second extrapolation | |
292 | (&(TrackParam[i2]))->ExtrapToZ(extZ[1]); | |
293 | return; | |
294 | } | |
295 | ||
04b5ea16 | 296 | //__________________________________________________________________________ |
889a0215 | 297 | void AliMUONTrackParam::ExtrapToVertex(Double_t xVtx, Double_t yVtx, Double_t zVtx) |
04b5ea16 | 298 | { |
299 | // Extrapolation to the vertex. | |
300 | // Returns the track parameters resulting from the extrapolation, | |
301 | // in the current TrackParam. | |
956019b6 | 302 | // Changes parameters according to Branson correction through the absorber |
04b5ea16 | 303 | |
5b64e914 | 304 | Double_t zAbsorber = -503.0; // to be coherent with the Geant absorber geometry !!!! |
305 | // spectro. (z<0) | |
04b5ea16 | 306 | // Extrapolates track parameters upstream to the "Z" end of the front absorber |
b45fd22b | 307 | ExtrapToZ(zAbsorber); // !!! |
5b64e914 | 308 | // Makes Branson correction (multiple scattering + energy loss) |
889a0215 | 309 | BransonCorrection(xVtx,yVtx,zVtx); |
5b64e914 | 310 | // Makes a simple magnetic field correction through the absorber |
b45fd22b | 311 | FieldCorrection(zAbsorber); |
04b5ea16 | 312 | } |
313 | ||
43af2cb6 | 314 | |
315 | // Keep this version for future developments | |
04b5ea16 | 316 | //__________________________________________________________________________ |
43af2cb6 | 317 | // void AliMUONTrackParam::BransonCorrection() |
318 | // { | |
319 | // // Branson correction of track parameters | |
320 | // // the entry parameters have to be calculated at the end of the absorber | |
321 | // Double_t zEndAbsorber, zBP, xBP, yBP; | |
322 | // Double_t pYZ, pX, pY, pZ, pTotal, xEndAbsorber, yEndAbsorber, radiusEndAbsorber2, pT, theta; | |
323 | // Int_t sign; | |
324 | // // Would it be possible to calculate all that from Geant configuration ???? | |
325 | // // and to get the Branson parameters from a function in ABSO module ???? | |
326 | // // with an eventual contribution from other detectors like START ???? | |
327 | // // Radiation lengths outer part theta > 3 degres | |
328 | // static Double_t x01[9] = { 18.8, // C (cm) | |
329 | // 10.397, // Concrete (cm) | |
330 | // 0.56, // Plomb (cm) | |
331 | // 47.26, // Polyethylene (cm) | |
332 | // 0.56, // Plomb (cm) | |
333 | // 47.26, // Polyethylene (cm) | |
334 | // 0.56, // Plomb (cm) | |
335 | // 47.26, // Polyethylene (cm) | |
336 | // 0.56 }; // Plomb (cm) | |
337 | // // inner part theta < 3 degres | |
338 | // static Double_t x02[3] = { 18.8, // C (cm) | |
339 | // 10.397, // Concrete (cm) | |
340 | // 0.35 }; // W (cm) | |
341 | // // z positions of the materials inside the absober outer part theta > 3 degres | |
342 | // static Double_t z1[10] = { 90, 315, 467, 472, 477, 482, 487, 492, 497, 502 }; | |
343 | // // inner part theta < 3 degres | |
344 | // static Double_t z2[4] = { 90, 315, 467, 503 }; | |
345 | // static Bool_t first = kTRUE; | |
346 | // static Double_t zBP1, zBP2, rLimit; | |
347 | // // Calculates z positions of the Branson's planes: zBP1 for outer part and zBP2 for inner part (only at the first call) | |
348 | // if (first) { | |
349 | // first = kFALSE; | |
350 | // Double_t aNBP = 0.0; | |
351 | // Double_t aDBP = 0.0; | |
352 | // Int_t iBound; | |
353 | ||
354 | // for (iBound = 0; iBound < 9; iBound++) { | |
355 | // aNBP = aNBP + | |
356 | // (z1[iBound+1] * z1[iBound+1] * z1[iBound+1] - | |
357 | // z1[iBound] * z1[iBound] * z1[iBound] ) / x01[iBound]; | |
358 | // aDBP = aDBP + | |
359 | // (z1[iBound+1] * z1[iBound+1] - z1[iBound] * z1[iBound] ) / x01[iBound]; | |
360 | // } | |
361 | // zBP1 = (2.0 * aNBP) / (3.0 * aDBP); | |
362 | // aNBP = 0.0; | |
363 | // aDBP = 0.0; | |
364 | // for (iBound = 0; iBound < 3; iBound++) { | |
365 | // aNBP = aNBP + | |
366 | // (z2[iBound+1] * z2[iBound+1] * z2[iBound+1] - | |
367 | // z2[iBound] * z2[iBound ] * z2[iBound] ) / x02[iBound]; | |
368 | // aDBP = aDBP + | |
369 | // (z2[iBound+1] * z2[iBound+1] - z2[iBound] * z2[iBound]) / x02[iBound]; | |
370 | // } | |
371 | // zBP2 = (2.0 * aNBP) / (3.0 * aDBP); | |
372 | // rLimit = z2[3] * TMath::Tan(3.0 * (TMath::Pi()) / 180.); | |
373 | // } | |
374 | ||
375 | // pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); | |
376 | // sign = 1; | |
377 | // if (fInverseBendingMomentum < 0) sign = -1; | |
378 | // pZ = pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); | |
379 | // pX = pZ * fNonBendingSlope; | |
380 | // pY = pZ * fBendingSlope; | |
381 | // pTotal = TMath::Sqrt(pYZ *pYZ + pX * pX); | |
382 | // xEndAbsorber = fNonBendingCoor; | |
383 | // yEndAbsorber = fBendingCoor; | |
384 | // radiusEndAbsorber2 = xEndAbsorber * xEndAbsorber + yEndAbsorber * yEndAbsorber; | |
385 | ||
386 | // if (radiusEndAbsorber2 > rLimit*rLimit) { | |
387 | // zEndAbsorber = z1[9]; | |
388 | // zBP = zBP1; | |
389 | // } else { | |
390 | // zEndAbsorber = z2[3]; | |
391 | // zBP = zBP2; | |
392 | // } | |
393 | ||
394 | // xBP = xEndAbsorber - (pX / pZ) * (zEndAbsorber - zBP); | |
395 | // yBP = yEndAbsorber - (pY / pZ) * (zEndAbsorber - zBP); | |
396 | ||
397 | // // new parameters after Branson and energy loss corrections | |
398 | // pZ = pTotal * zBP / TMath::Sqrt(xBP * xBP + yBP * yBP + zBP * zBP); | |
399 | // pX = pZ * xBP / zBP; | |
400 | // pY = pZ * yBP / zBP; | |
401 | // fBendingSlope = pY / pZ; | |
402 | // fNonBendingSlope = pX / pZ; | |
403 | ||
404 | // pT = TMath::Sqrt(pX * pX + pY * pY); | |
405 | // theta = TMath::ATan2(pT, pZ); | |
406 | // pTotal = | |
407 | // TotalMomentumEnergyLoss(rLimit, pTotal, theta, xEndAbsorber, yEndAbsorber); | |
408 | ||
409 | // fInverseBendingMomentum = (sign / pTotal) * | |
410 | // TMath::Sqrt(1.0 + | |
411 | // fBendingSlope * fBendingSlope + | |
412 | // fNonBendingSlope * fNonBendingSlope) / | |
413 | // TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope); | |
414 | ||
415 | // // vertex position at (0,0,0) | |
416 | // // should be taken from vertex measurement ??? | |
417 | // fBendingCoor = 0.0; | |
418 | // fNonBendingCoor = 0; | |
419 | // fZ= 0; | |
420 | // } | |
421 | ||
889a0215 | 422 | void AliMUONTrackParam::BransonCorrection(Double_t xVtx,Double_t yVtx,Double_t zVtx) |
04b5ea16 | 423 | { |
424 | // Branson correction of track parameters | |
425 | // the entry parameters have to be calculated at the end of the absorber | |
43af2cb6 | 426 | // simplified version: the z positions of Branson's planes are no longer calculated |
427 | // but are given as inputs. One can use the macros MUONTestAbso.C and DrawTestAbso.C | |
428 | // to test this correction. | |
04b5ea16 | 429 | // Would it be possible to calculate all that from Geant configuration ???? |
956019b6 | 430 | // and to get the Branson parameters from a function in ABSO module ???? |
431 | // with an eventual contribution from other detectors like START ???? | |
889a0215 | 432 | //change to take into account the vertex postition (real, reconstruct,....) |
433 | ||
43af2cb6 | 434 | Double_t zBP, xBP, yBP; |
435 | Double_t pYZ, pX, pY, pZ, pTotal, xEndAbsorber, yEndAbsorber, radiusEndAbsorber2, pT, theta; | |
436 | Int_t sign; | |
04b5ea16 | 437 | static Bool_t first = kTRUE; |
b45fd22b | 438 | static Double_t zBP1, zBP2, rLimit, thetaLimit, zEndAbsorber; |
43af2cb6 | 439 | // zBP1 for outer part and zBP2 for inner part (only at the first call) |
04b5ea16 | 440 | if (first) { |
441 | first = kFALSE; | |
43af2cb6 | 442 | |
5b64e914 | 443 | zEndAbsorber = -503; // spectro (z<0) |
b45fd22b | 444 | thetaLimit = 3.0 * (TMath::Pi()) / 180.; |
5b64e914 | 445 | rLimit = TMath::Abs(zEndAbsorber) * TMath::Tan(thetaLimit); |
446 | zBP1 = -450; // values close to those calculated with EvalAbso.C | |
447 | zBP2 = -480; | |
04b5ea16 | 448 | } |
449 | ||
450 | pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); | |
451 | sign = 1; | |
b8dc484b | 452 | if (fInverseBendingMomentum < 0) sign = -1; |
453 | pZ = Pz(); | |
454 | pX = Px(); | |
455 | pY = Py(); | |
04b5ea16 | 456 | pTotal = TMath::Sqrt(pYZ *pYZ + pX * pX); |
457 | xEndAbsorber = fNonBendingCoor; | |
458 | yEndAbsorber = fBendingCoor; | |
459 | radiusEndAbsorber2 = xEndAbsorber * xEndAbsorber + yEndAbsorber * yEndAbsorber; | |
460 | ||
461 | if (radiusEndAbsorber2 > rLimit*rLimit) { | |
04b5ea16 | 462 | zBP = zBP1; |
463 | } else { | |
04b5ea16 | 464 | zBP = zBP2; |
465 | } | |
466 | ||
467 | xBP = xEndAbsorber - (pX / pZ) * (zEndAbsorber - zBP); | |
468 | yBP = yEndAbsorber - (pY / pZ) * (zEndAbsorber - zBP); | |
469 | ||
470 | // new parameters after Branson and energy loss corrections | |
b45fd22b | 471 | // Float_t zSmear = zBP - gRandom->Gaus(0.,2.); // !!! possible smearing of Z vertex position |
889a0215 | 472 | |
473 | Float_t zSmear = zBP ; | |
b45fd22b | 474 | |
889a0215 | 475 | pZ = pTotal * (zSmear-zVtx) / TMath::Sqrt((xBP-xVtx) * (xBP-xVtx) + (yBP-yVtx) * (yBP-yVtx) +( zSmear-zVtx) * (zSmear-zVtx) ); |
476 | pX = pZ * (xBP - xVtx)/ (zSmear-zVtx); | |
477 | pY = pZ * (yBP - yVtx) / (zSmear-zVtx); | |
04b5ea16 | 478 | fBendingSlope = pY / pZ; |
479 | fNonBendingSlope = pX / pZ; | |
5b64e914 | 480 | |
04b5ea16 | 481 | |
482 | pT = TMath::Sqrt(pX * pX + pY * pY); | |
5b64e914 | 483 | theta = TMath::ATan2(pT, TMath::Abs(pZ)); |
b45fd22b | 484 | pTotal = TotalMomentumEnergyLoss(thetaLimit, pTotal, theta); |
04b5ea16 | 485 | |
486 | fInverseBendingMomentum = (sign / pTotal) * | |
487 | TMath::Sqrt(1.0 + | |
488 | fBendingSlope * fBendingSlope + | |
489 | fNonBendingSlope * fNonBendingSlope) / | |
490 | TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope); | |
491 | ||
492 | // vertex position at (0,0,0) | |
493 | // should be taken from vertex measurement ??? | |
889a0215 | 494 | |
495 | fBendingCoor = xVtx; | |
496 | fNonBendingCoor = yVtx; | |
497 | fZ= zVtx; | |
498 | ||
04b5ea16 | 499 | } |
b45fd22b | 500 | |
04b5ea16 | 501 | //__________________________________________________________________________ |
b45fd22b | 502 | Double_t AliMUONTrackParam::TotalMomentumEnergyLoss(Double_t thetaLimit, Double_t pTotal, Double_t theta) |
04b5ea16 | 503 | { |
504 | // Returns the total momentum corrected from energy loss in the front absorber | |
43af2cb6 | 505 | // One can use the macros MUONTestAbso.C and DrawTestAbso.C |
506 | // to test this correction. | |
b45fd22b | 507 | // Momentum energy loss behaviour evaluated with the simulation of single muons (april 2002) |
04b5ea16 | 508 | Double_t deltaP, pTotalCorrected; |
509 | ||
b45fd22b | 510 | // Parametrization to be redone according to change of absorber material ???? |
956019b6 | 511 | // See remark in function BransonCorrection !!!! |
04b5ea16 | 512 | // The name is not so good, and there are many arguments !!!! |
b45fd22b | 513 | if (theta < thetaLimit ) { |
514 | if (pTotal < 20) { | |
515 | deltaP = 2.5938 + 0.0570 * pTotal - 0.001151 * pTotal * pTotal; | |
04b5ea16 | 516 | } else { |
b45fd22b | 517 | deltaP = 3.0714 + 0.011767 *pTotal; |
04b5ea16 | 518 | } |
96a96c2b | 519 | deltaP *= 0.75; // AZ |
04b5ea16 | 520 | } else { |
b45fd22b | 521 | if (pTotal < 20) { |
522 | deltaP = 2.1207 + 0.05478 * pTotal - 0.00145079 * pTotal * pTotal; | |
04b5ea16 | 523 | } else { |
b45fd22b | 524 | deltaP = 2.6069 + 0.0051705 * pTotal; |
04b5ea16 | 525 | } |
96a96c2b | 526 | deltaP *= 0.9; // AZ |
04b5ea16 | 527 | } |
528 | pTotalCorrected = pTotal + deltaP / TMath::Cos(theta); | |
529 | return pTotalCorrected; | |
530 | } | |
531 | ||
b45fd22b | 532 | //__________________________________________________________________________ |
533 | void AliMUONTrackParam::FieldCorrection(Double_t Z) | |
534 | { | |
535 | // | |
536 | // Correction of the effect of the magnetic field in the absorber | |
537 | // Assume a constant field along Z axis. | |
538 | ||
539 | Float_t b[3],x[3]; | |
540 | Double_t bZ; | |
541 | Double_t pYZ,pX,pY,pZ,pT; | |
542 | Double_t pXNew,pYNew; | |
543 | Double_t c; | |
544 | ||
545 | pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); | |
546 | c = TMath::Sign(1.0,fInverseBendingMomentum); // particle charge | |
547 | ||
b8dc484b | 548 | pZ = Pz(); |
549 | pX = Px(); | |
550 | pY = Py(); | |
b45fd22b | 551 | pT = TMath::Sqrt(pX*pX+pY*pY); |
552 | ||
5b64e914 | 553 | if (TMath::Abs(pZ) <= 0) return; |
b45fd22b | 554 | x[2] = Z/2; |
555 | x[0] = x[2]*fNonBendingSlope; | |
556 | x[1] = x[2]*fBendingSlope; | |
557 | ||
558 | // Take magn. field value at position x. | |
1a38e749 | 559 | fkField->Field(x, b); |
b45fd22b | 560 | bZ = b[2]; |
561 | ||
562 | // Transverse momentum rotation | |
563 | // Parameterized with the study of DeltaPhi = phiReco - phiGen as a function of pZ. | |
5b64e914 | 564 | Double_t phiShift = c*0.436*0.0003*bZ*Z/pZ; |
b45fd22b | 565 | // Rotate momentum around Z axis. |
566 | pXNew = pX*TMath::Cos(phiShift) - pY*TMath::Sin(phiShift); | |
567 | pYNew = pX*TMath::Sin(phiShift) + pY*TMath::Cos(phiShift); | |
568 | ||
569 | fBendingSlope = pYNew / pZ; | |
570 | fNonBendingSlope = pXNew / pZ; | |
571 | ||
572 | fInverseBendingMomentum = c / TMath::Sqrt(pYNew*pYNew+pZ*pZ); | |
573 | ||
b8dc484b | 574 | } |
575 | //__________________________________________________________________________ | |
6464217e | 576 | Double_t AliMUONTrackParam::Px() const |
b8dc484b | 577 | { |
578 | // return px from track paramaters | |
579 | Double_t pYZ, pZ, pX; | |
580 | pYZ = 0; | |
581 | if ( TMath::Abs(fInverseBendingMomentum) > 0 ) | |
582 | pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); | |
583 | pZ = -pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); // spectro. (z<0) | |
584 | pX = pZ * fNonBendingSlope; | |
585 | return pX; | |
586 | } | |
587 | //__________________________________________________________________________ | |
6464217e | 588 | Double_t AliMUONTrackParam::Py() const |
b8dc484b | 589 | { |
590 | // return px from track paramaters | |
591 | Double_t pYZ, pZ, pY; | |
592 | pYZ = 0; | |
593 | if ( TMath::Abs(fInverseBendingMomentum) > 0 ) | |
594 | pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); | |
595 | pZ = -pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); // spectro. (z<0) | |
596 | pY = pZ * fBendingSlope; | |
597 | return pY; | |
598 | } | |
599 | //__________________________________________________________________________ | |
6464217e | 600 | Double_t AliMUONTrackParam::Pz() const |
b8dc484b | 601 | { |
602 | // return px from track paramaters | |
603 | Double_t pYZ, pZ; | |
604 | pYZ = 0; | |
605 | if ( TMath::Abs(fInverseBendingMomentum) > 0 ) | |
606 | pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); | |
607 | pZ = -pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); // spectro. (z<0) | |
608 | return pZ; | |
609 | } | |
610 | //__________________________________________________________________________ | |
6464217e | 611 | Double_t AliMUONTrackParam::P() const |
b8dc484b | 612 | { |
613 | // return p from track paramaters | |
614 | Double_t pYZ, pZ, p; | |
615 | pYZ = 0; | |
616 | if ( TMath::Abs(fInverseBendingMomentum) > 0 ) | |
617 | pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); | |
618 | pZ = -pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); // spectro. (z<0) | |
619 | p = TMath::Abs(pZ) * | |
620 | TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope + fNonBendingSlope * fNonBendingSlope); | |
621 | return p; | |
622 | ||
b45fd22b | 623 | } |
4d03a78e | 624 | //__________________________________________________________________________ |
625 | void AliMUONTrackParam::ExtrapOneStepHelix(Double_t charge, Double_t step, | |
f161a467 | 626 | Double_t *vect, Double_t *vout) const |
4d03a78e | 627 | { |
628 | // ****************************************************************** | |
629 | // * * | |
630 | // * Performs the tracking of one step in a magnetic field * | |
631 | // * The trajectory is assumed to be a helix in a constant field * | |
632 | // * taken at the mid point of the step. * | |
633 | // * Parameters: * | |
634 | // * input * | |
635 | // * STEP =arc length of the step asked * | |
636 | // * VECT =input vector (position,direction cos and momentum) * | |
637 | // * CHARGE= electric charge of the particle * | |
638 | // * output * | |
639 | // * VOUT = same as VECT after completion of the step * | |
640 | // * * | |
641 | // * ==>Called by : <USER>, GUSWIM * | |
642 | // * Author m.hansroul ********* * | |
643 | // * modified s.egli, s.v.levonian * | |
644 | // * modified v.perevoztchikov | |
645 | // * * | |
646 | // ****************************************************************** | |
647 | // | |
648 | ||
649 | // modif: everything in double precision | |
650 | ||
651 | Double_t xyz[3], h[4], hxp[3]; | |
652 | Double_t h2xy, hp, rho, tet; | |
653 | Double_t sint, sintt, tsint, cos1t; | |
654 | Double_t f1, f2, f3, f4, f5, f6; | |
655 | ||
58443fe3 | 656 | const Int_t kix = 0; |
657 | const Int_t kiy = 1; | |
658 | const Int_t kiz = 2; | |
659 | const Int_t kipx = 3; | |
660 | const Int_t kipy = 4; | |
661 | const Int_t kipz = 5; | |
662 | const Int_t kipp = 6; | |
4d03a78e | 663 | |
58443fe3 | 664 | const Double_t kec = 2.9979251e-4; |
4d03a78e | 665 | // |
666 | // ------------------------------------------------------------------ | |
667 | // | |
668 | // units are kgauss,centimeters,gev/c | |
669 | // | |
58443fe3 | 670 | vout[kipp] = vect[kipp]; |
4d03a78e | 671 | if (TMath::Abs(charge) < 0.00001) { |
672 | for (Int_t i = 0; i < 3; i++) { | |
673 | vout[i] = vect[i] + step * vect[i+3]; | |
674 | vout[i+3] = vect[i+3]; | |
675 | } | |
676 | return; | |
677 | } | |
58443fe3 | 678 | xyz[0] = vect[kix] + 0.5 * step * vect[kipx]; |
679 | xyz[1] = vect[kiy] + 0.5 * step * vect[kipy]; | |
680 | xyz[2] = vect[kiz] + 0.5 * step * vect[kipz]; | |
4d03a78e | 681 | |
682 | //cmodif: call gufld (xyz, h) changed into: | |
683 | GetField (xyz, h); | |
684 | ||
685 | h2xy = h[0]*h[0] + h[1]*h[1]; | |
686 | h[3] = h[2]*h[2]+ h2xy; | |
687 | if (h[3] < 1.e-12) { | |
688 | for (Int_t i = 0; i < 3; i++) { | |
689 | vout[i] = vect[i] + step * vect[i+3]; | |
690 | vout[i+3] = vect[i+3]; | |
691 | } | |
692 | return; | |
693 | } | |
694 | if (h2xy < 1.e-12*h[3]) { | |
695 | ExtrapOneStepHelix3(charge*h[2], step, vect, vout); | |
696 | return; | |
697 | } | |
698 | h[3] = TMath::Sqrt(h[3]); | |
699 | h[0] /= h[3]; | |
700 | h[1] /= h[3]; | |
701 | h[2] /= h[3]; | |
58443fe3 | 702 | h[3] *= kec; |
4d03a78e | 703 | |
58443fe3 | 704 | hxp[0] = h[1]*vect[kipz] - h[2]*vect[kipy]; |
705 | hxp[1] = h[2]*vect[kipx] - h[0]*vect[kipz]; | |
706 | hxp[2] = h[0]*vect[kipy] - h[1]*vect[kipx]; | |
4d03a78e | 707 | |
58443fe3 | 708 | hp = h[0]*vect[kipx] + h[1]*vect[kipy] + h[2]*vect[kipz]; |
4d03a78e | 709 | |
58443fe3 | 710 | rho = -charge*h[3]/vect[kipp]; |
4d03a78e | 711 | tet = rho * step; |
712 | ||
713 | if (TMath::Abs(tet) > 0.15) { | |
714 | sint = TMath::Sin(tet); | |
715 | sintt = (sint/tet); | |
716 | tsint = (tet-sint)/tet; | |
717 | cos1t = 2.*(TMath::Sin(0.5*tet))*(TMath::Sin(0.5*tet))/tet; | |
718 | } else { | |
719 | tsint = tet*tet/36.; | |
720 | sintt = (1. - tsint); | |
721 | sint = tet*sintt; | |
722 | cos1t = 0.5*tet; | |
723 | } | |
724 | ||
725 | f1 = step * sintt; | |
726 | f2 = step * cos1t; | |
727 | f3 = step * tsint * hp; | |
728 | f4 = -tet*cos1t; | |
729 | f5 = sint; | |
730 | f6 = tet * cos1t * hp; | |
731 | ||
58443fe3 | 732 | vout[kix] = vect[kix] + f1*vect[kipx] + f2*hxp[0] + f3*h[0]; |
733 | vout[kiy] = vect[kiy] + f1*vect[kipy] + f2*hxp[1] + f3*h[1]; | |
734 | vout[kiz] = vect[kiz] + f1*vect[kipz] + f2*hxp[2] + f3*h[2]; | |
4d03a78e | 735 | |
58443fe3 | 736 | vout[kipx] = vect[kipx] + f4*vect[kipx] + f5*hxp[0] + f6*h[0]; |
737 | vout[kipy] = vect[kipy] + f4*vect[kipy] + f5*hxp[1] + f6*h[1]; | |
738 | vout[kipz] = vect[kipz] + f4*vect[kipz] + f5*hxp[2] + f6*h[2]; | |
4d03a78e | 739 | |
740 | return; | |
741 | } | |
742 | ||
743 | //__________________________________________________________________________ | |
744 | void AliMUONTrackParam::ExtrapOneStepHelix3(Double_t field, Double_t step, | |
f161a467 | 745 | Double_t *vect, Double_t *vout) const |
4d03a78e | 746 | { |
747 | // | |
748 | // ****************************************************************** | |
749 | // * * | |
750 | // * Tracking routine in a constant field oriented * | |
751 | // * along axis 3 * | |
752 | // * Tracking is performed with a conventional * | |
753 | // * helix step method * | |
754 | // * * | |
755 | // * ==>Called by : <USER>, GUSWIM * | |
756 | // * Authors R.Brun, M.Hansroul ********* * | |
757 | // * Rewritten V.Perevoztchikov | |
758 | // * * | |
759 | // ****************************************************************** | |
760 | // | |
761 | ||
762 | Double_t hxp[3]; | |
763 | Double_t h4, hp, rho, tet; | |
764 | Double_t sint, sintt, tsint, cos1t; | |
765 | Double_t f1, f2, f3, f4, f5, f6; | |
766 | ||
58443fe3 | 767 | const Int_t kix = 0; |
768 | const Int_t kiy = 1; | |
769 | const Int_t kiz = 2; | |
770 | const Int_t kipx = 3; | |
771 | const Int_t kipy = 4; | |
772 | const Int_t kipz = 5; | |
773 | const Int_t kipp = 6; | |
4d03a78e | 774 | |
58443fe3 | 775 | const Double_t kec = 2.9979251e-4; |
4d03a78e | 776 | |
777 | // | |
778 | // ------------------------------------------------------------------ | |
779 | // | |
780 | // units are kgauss,centimeters,gev/c | |
781 | // | |
58443fe3 | 782 | vout[kipp] = vect[kipp]; |
783 | h4 = field * kec; | |
4d03a78e | 784 | |
58443fe3 | 785 | hxp[0] = - vect[kipy]; |
786 | hxp[1] = + vect[kipx]; | |
4d03a78e | 787 | |
58443fe3 | 788 | hp = vect[kipz]; |
4d03a78e | 789 | |
58443fe3 | 790 | rho = -h4/vect[kipp]; |
4d03a78e | 791 | tet = rho * step; |
792 | if (TMath::Abs(tet) > 0.15) { | |
793 | sint = TMath::Sin(tet); | |
794 | sintt = (sint/tet); | |
795 | tsint = (tet-sint)/tet; | |
796 | cos1t = 2.* TMath::Sin(0.5*tet) * TMath::Sin(0.5*tet)/tet; | |
797 | } else { | |
798 | tsint = tet*tet/36.; | |
799 | sintt = (1. - tsint); | |
800 | sint = tet*sintt; | |
801 | cos1t = 0.5*tet; | |
802 | } | |
803 | ||
804 | f1 = step * sintt; | |
805 | f2 = step * cos1t; | |
806 | f3 = step * tsint * hp; | |
807 | f4 = -tet*cos1t; | |
808 | f5 = sint; | |
809 | f6 = tet * cos1t * hp; | |
810 | ||
58443fe3 | 811 | vout[kix] = vect[kix] + f1*vect[kipx] + f2*hxp[0]; |
812 | vout[kiy] = vect[kiy] + f1*vect[kipy] + f2*hxp[1]; | |
813 | vout[kiz] = vect[kiz] + f1*vect[kipz] + f3; | |
4d03a78e | 814 | |
58443fe3 | 815 | vout[kipx] = vect[kipx] + f4*vect[kipx] + f5*hxp[0]; |
816 | vout[kipy] = vect[kipy] + f4*vect[kipy] + f5*hxp[1]; | |
817 | vout[kipz] = vect[kipz] + f4*vect[kipz] + f6; | |
4d03a78e | 818 | |
819 | return; | |
820 | } | |
821 | //__________________________________________________________________________ | |
822 | void AliMUONTrackParam::ExtrapOneStepRungekutta(Double_t charge, Double_t step, | |
f161a467 | 823 | Double_t* vect, Double_t* vout) const |
4d03a78e | 824 | { |
825 | // | |
826 | // ****************************************************************** | |
827 | // * * | |
828 | // * Runge-Kutta method for tracking a particle through a magnetic * | |
829 | // * field. Uses Nystroem algorithm (See Handbook Nat. Bur. of * | |
830 | // * Standards, procedure 25.5.20) * | |
831 | // * * | |
832 | // * Input parameters * | |
833 | // * CHARGE Particle charge * | |
834 | // * STEP Step size * | |
835 | // * VECT Initial co-ords,direction cosines,momentum * | |
836 | // * Output parameters * | |
837 | // * VOUT Output co-ords,direction cosines,momentum * | |
838 | // * User routine called * | |
839 | // * CALL GUFLD(X,F) * | |
840 | // * * | |
841 | // * ==>Called by : <USER>, GUSWIM * | |
842 | // * Authors R.Brun, M.Hansroul ********* * | |
843 | // * V.Perevoztchikov (CUT STEP implementation) * | |
844 | // * * | |
845 | // * * | |
846 | // ****************************************************************** | |
847 | // | |
848 | ||
849 | Double_t h2, h4, f[4]; | |
850 | Double_t xyzt[3], a, b, c, ph,ph2; | |
851 | Double_t secxs[4],secys[4],seczs[4],hxp[3]; | |
852 | Double_t g1, g2, g3, g4, g5, g6, ang2, dxt, dyt, dzt; | |
853 | Double_t est, at, bt, ct, cba; | |
854 | Double_t f1, f2, f3, f4, rho, tet, hnorm, hp, rho1, sint, cost; | |
855 | ||
856 | Double_t x; | |
857 | Double_t y; | |
858 | Double_t z; | |
859 | ||
860 | Double_t xt; | |
861 | Double_t yt; | |
862 | Double_t zt; | |
863 | ||
864 | Double_t maxit = 1992; | |
865 | Double_t maxcut = 11; | |
866 | ||
58443fe3 | 867 | const Double_t kdlt = 1e-4; |
868 | const Double_t kdlt32 = kdlt/32.; | |
869 | const Double_t kthird = 1./3.; | |
870 | const Double_t khalf = 0.5; | |
871 | const Double_t kec = 2.9979251e-4; | |
872 | ||
873 | const Double_t kpisqua = 9.86960440109; | |
874 | const Int_t kix = 0; | |
875 | const Int_t kiy = 1; | |
876 | const Int_t kiz = 2; | |
877 | const Int_t kipx = 3; | |
878 | const Int_t kipy = 4; | |
879 | const Int_t kipz = 5; | |
4d03a78e | 880 | |
881 | // *. | |
882 | // *. ------------------------------------------------------------------ | |
883 | // *. | |
884 | // * this constant is for units cm,gev/c and kgauss | |
885 | // * | |
886 | Int_t iter = 0; | |
887 | Int_t ncut = 0; | |
888 | for(Int_t j = 0; j < 7; j++) | |
889 | vout[j] = vect[j]; | |
890 | ||
58443fe3 | 891 | Double_t pinv = kec * charge / vect[6]; |
4d03a78e | 892 | Double_t tl = 0.; |
893 | Double_t h = step; | |
894 | Double_t rest; | |
895 | ||
896 | ||
897 | do { | |
898 | rest = step - tl; | |
899 | if (TMath::Abs(h) > TMath::Abs(rest)) h = rest; | |
900 | //cmodif: call gufld(vout,f) changed into: | |
901 | ||
902 | GetField(vout,f); | |
903 | ||
904 | // * | |
905 | // * start of integration | |
906 | // * | |
907 | x = vout[0]; | |
908 | y = vout[1]; | |
909 | z = vout[2]; | |
910 | a = vout[3]; | |
911 | b = vout[4]; | |
912 | c = vout[5]; | |
913 | ||
58443fe3 | 914 | h2 = khalf * h; |
915 | h4 = khalf * h2; | |
4d03a78e | 916 | ph = pinv * h; |
58443fe3 | 917 | ph2 = khalf * ph; |
4d03a78e | 918 | secxs[0] = (b * f[2] - c * f[1]) * ph2; |
919 | secys[0] = (c * f[0] - a * f[2]) * ph2; | |
920 | seczs[0] = (a * f[1] - b * f[0]) * ph2; | |
921 | ang2 = (secxs[0]*secxs[0] + secys[0]*secys[0] + seczs[0]*seczs[0]); | |
58443fe3 | 922 | if (ang2 > kpisqua) break; |
4d03a78e | 923 | |
924 | dxt = h2 * a + h4 * secxs[0]; | |
925 | dyt = h2 * b + h4 * secys[0]; | |
926 | dzt = h2 * c + h4 * seczs[0]; | |
927 | xt = x + dxt; | |
928 | yt = y + dyt; | |
929 | zt = z + dzt; | |
930 | // * | |
931 | // * second intermediate point | |
932 | // * | |
933 | ||
934 | est = TMath::Abs(dxt) + TMath::Abs(dyt) + TMath::Abs(dzt); | |
935 | if (est > h) { | |
936 | if (ncut++ > maxcut) break; | |
58443fe3 | 937 | h *= khalf; |
4d03a78e | 938 | continue; |
939 | } | |
940 | ||
941 | xyzt[0] = xt; | |
942 | xyzt[1] = yt; | |
943 | xyzt[2] = zt; | |
944 | ||
945 | //cmodif: call gufld(xyzt,f) changed into: | |
946 | GetField(xyzt,f); | |
947 | ||
948 | at = a + secxs[0]; | |
949 | bt = b + secys[0]; | |
950 | ct = c + seczs[0]; | |
951 | ||
952 | secxs[1] = (bt * f[2] - ct * f[1]) * ph2; | |
953 | secys[1] = (ct * f[0] - at * f[2]) * ph2; | |
954 | seczs[1] = (at * f[1] - bt * f[0]) * ph2; | |
955 | at = a + secxs[1]; | |
956 | bt = b + secys[1]; | |
957 | ct = c + seczs[1]; | |
958 | secxs[2] = (bt * f[2] - ct * f[1]) * ph2; | |
959 | secys[2] = (ct * f[0] - at * f[2]) * ph2; | |
960 | seczs[2] = (at * f[1] - bt * f[0]) * ph2; | |
961 | dxt = h * (a + secxs[2]); | |
962 | dyt = h * (b + secys[2]); | |
963 | dzt = h * (c + seczs[2]); | |
964 | xt = x + dxt; | |
965 | yt = y + dyt; | |
966 | zt = z + dzt; | |
967 | at = a + 2.*secxs[2]; | |
968 | bt = b + 2.*secys[2]; | |
969 | ct = c + 2.*seczs[2]; | |
970 | ||
971 | est = TMath::Abs(dxt)+TMath::Abs(dyt)+TMath::Abs(dzt); | |
972 | if (est > 2.*TMath::Abs(h)) { | |
973 | if (ncut++ > maxcut) break; | |
58443fe3 | 974 | h *= khalf; |
4d03a78e | 975 | continue; |
976 | } | |
977 | ||
978 | xyzt[0] = xt; | |
979 | xyzt[1] = yt; | |
980 | xyzt[2] = zt; | |
981 | ||
982 | //cmodif: call gufld(xyzt,f) changed into: | |
983 | GetField(xyzt,f); | |
984 | ||
58443fe3 | 985 | z = z + (c + (seczs[0] + seczs[1] + seczs[2]) * kthird) * h; |
986 | y = y + (b + (secys[0] + secys[1] + secys[2]) * kthird) * h; | |
987 | x = x + (a + (secxs[0] + secxs[1] + secxs[2]) * kthird) * h; | |
4d03a78e | 988 | |
989 | secxs[3] = (bt*f[2] - ct*f[1])* ph2; | |
990 | secys[3] = (ct*f[0] - at*f[2])* ph2; | |
991 | seczs[3] = (at*f[1] - bt*f[0])* ph2; | |
58443fe3 | 992 | a = a+(secxs[0]+secxs[3]+2. * (secxs[1]+secxs[2])) * kthird; |
993 | b = b+(secys[0]+secys[3]+2. * (secys[1]+secys[2])) * kthird; | |
994 | c = c+(seczs[0]+seczs[3]+2. * (seczs[1]+seczs[2])) * kthird; | |
4d03a78e | 995 | |
996 | est = TMath::Abs(secxs[0]+secxs[3] - (secxs[1]+secxs[2])) | |
997 | + TMath::Abs(secys[0]+secys[3] - (secys[1]+secys[2])) | |
998 | + TMath::Abs(seczs[0]+seczs[3] - (seczs[1]+seczs[2])); | |
999 | ||
58443fe3 | 1000 | if (est > kdlt && TMath::Abs(h) > 1.e-4) { |
4d03a78e | 1001 | if (ncut++ > maxcut) break; |
58443fe3 | 1002 | h *= khalf; |
4d03a78e | 1003 | continue; |
1004 | } | |
1005 | ||
1006 | ncut = 0; | |
1007 | // * if too many iterations, go to helix | |
1008 | if (iter++ > maxit) break; | |
1009 | ||
1010 | tl += h; | |
58443fe3 | 1011 | if (est < kdlt32) |
4d03a78e | 1012 | h *= 2.; |
1013 | cba = 1./ TMath::Sqrt(a*a + b*b + c*c); | |
1014 | vout[0] = x; | |
1015 | vout[1] = y; | |
1016 | vout[2] = z; | |
1017 | vout[3] = cba*a; | |
1018 | vout[4] = cba*b; | |
1019 | vout[5] = cba*c; | |
1020 | rest = step - tl; | |
1021 | if (step < 0.) rest = -rest; | |
1022 | if (rest < 1.e-5*TMath::Abs(step)) return; | |
1023 | ||
1024 | } while(1); | |
1025 | ||
1026 | // angle too big, use helix | |
1027 | ||
1028 | f1 = f[0]; | |
1029 | f2 = f[1]; | |
1030 | f3 = f[2]; | |
1031 | f4 = TMath::Sqrt(f1*f1+f2*f2+f3*f3); | |
1032 | rho = -f4*pinv; | |
1033 | tet = rho * step; | |
1034 | ||
1035 | hnorm = 1./f4; | |
1036 | f1 = f1*hnorm; | |
1037 | f2 = f2*hnorm; | |
1038 | f3 = f3*hnorm; | |
1039 | ||
58443fe3 | 1040 | hxp[0] = f2*vect[kipz] - f3*vect[kipy]; |
1041 | hxp[1] = f3*vect[kipx] - f1*vect[kipz]; | |
1042 | hxp[2] = f1*vect[kipy] - f2*vect[kipx]; | |
4d03a78e | 1043 | |
58443fe3 | 1044 | hp = f1*vect[kipx] + f2*vect[kipy] + f3*vect[kipz]; |
4d03a78e | 1045 | |
1046 | rho1 = 1./rho; | |
1047 | sint = TMath::Sin(tet); | |
58443fe3 | 1048 | cost = 2.*TMath::Sin(khalf*tet)*TMath::Sin(khalf*tet); |
4d03a78e | 1049 | |
1050 | g1 = sint*rho1; | |
1051 | g2 = cost*rho1; | |
1052 | g3 = (tet-sint) * hp*rho1; | |
1053 | g4 = -cost; | |
1054 | g5 = sint; | |
1055 | g6 = cost * hp; | |
1056 | ||
58443fe3 | 1057 | vout[kix] = vect[kix] + g1*vect[kipx] + g2*hxp[0] + g3*f1; |
1058 | vout[kiy] = vect[kiy] + g1*vect[kipy] + g2*hxp[1] + g3*f2; | |
1059 | vout[kiz] = vect[kiz] + g1*vect[kipz] + g2*hxp[2] + g3*f3; | |
4d03a78e | 1060 | |
58443fe3 | 1061 | vout[kipx] = vect[kipx] + g4*vect[kipx] + g5*hxp[0] + g6*f1; |
1062 | vout[kipy] = vect[kipy] + g4*vect[kipy] + g5*hxp[1] + g6*f2; | |
1063 | vout[kipz] = vect[kipz] + g4*vect[kipz] + g5*hxp[2] + g6*f3; | |
4d03a78e | 1064 | |
1065 | return; | |
1066 | } | |
1067 | //___________________________________________________________ | |
f161a467 | 1068 | void AliMUONTrackParam::GetField(Double_t *Position, Double_t *Field) const |
4d03a78e | 1069 | { |
1a38e749 | 1070 | // interface for arguments in double precision (Why ? ChF) |
4d03a78e | 1071 | |
1072 | Float_t x[3], b[3]; | |
1073 | ||
1074 | x[0] = Position[0]; x[1] = Position[1]; x[2] = Position[2]; | |
1075 | ||
1a38e749 | 1076 | fkField->Field(x, b); |
4d03a78e | 1077 | Field[0] = b[0]; Field[1] = b[1]; Field[2] = b[2]; |
1078 | ||
1079 | return; | |
1080 | } | |
6464217e | 1081 | //_____________________________________________- |
1082 | void AliMUONTrackParam::Print(Option_t* opt) const | |
1083 | { | |
1084 | // | |
1085 | // Printing TrackParam information | |
1086 | // "full" option for printing all the information about the TrackParam | |
1087 | // | |
1088 | TString sopt(opt); | |
1089 | sopt.ToUpper(); | |
1090 | ||
1091 | if ( sopt.Contains("FULL") ) { | |
1092 | cout << "<AliMUONTrackParam> Bending P=" << setw(5) << setprecision(3) << 1./GetInverseBendingMomentum() << | |
1093 | ", NonBendSlope=" << setw(5) << setprecision(3) << GetNonBendingSlope()*180./TMath::Pi() << | |
1094 | ", BendSlope=" << setw(5) << setprecision(3) << GetBendingSlope()*180./TMath::Pi() << | |
1095 | ", (x,y,z)_IP=(" << setw(5) << setprecision(3) << GetNonBendingCoor() << | |
1096 | "," << setw(5) << setprecision(3) << GetBendingCoor() << | |
1097 | "," << setw(5) << setprecision(3) << GetZ() << | |
1098 | ") cm, (px,py,pz)=(" << setw(5) << setprecision(3) << Px() << | |
1099 | "," << setw(5) << setprecision(3) << Py() << | |
1100 | "," << setw(5) << setprecision(3) << Pz() << ") GeV/c" << endl; | |
1101 | } | |
1102 | else { | |
1103 | cout << "<AliMUONTrackParam>" << endl; | |
1104 | } | |
1105 | ||
1106 | } |