X-Git-Url: http://git.uio.no/git/?a=blobdiff_plain;f=MUON%2FAliMUONTrackParam.cxx;h=01beb2eb5aeb4ab252f73c457779fe65279b4e6b;hb=c8c88e5ddda0825dae3c4618eabe6c415c1c3a98;hp=e41ce1724fb7049289920f5fdc4f96219ffbeb36;hpb=a9e2aefa97f1153d6f61e580a32d396156706b7b;p=u%2Fmrichter%2FAliRoot.git diff --git a/MUON/AliMUONTrackParam.cxx b/MUON/AliMUONTrackParam.cxx index e41ce1724fb..01beb2eb5ae 100644 --- a/MUON/AliMUONTrackParam.cxx +++ b/MUON/AliMUONTrackParam.cxx @@ -13,84 +13,74 @@ * provided "as is" without express or implied warranty. * **************************************************************************/ -/* -$Log$ -Revision 1.1.2.3 2000/06/09 21:03:09 morsch -Make includes consistent with new file structure. +/* $Id$ */ -Revision 1.1.2.2 2000/06/09 12:58:05 gosset -Removed comment beginnings in Log sections of .cxx files -Suppressed most violations of coding rules - -Revision 1.1.2.1 2000/06/07 14:44:53 gosset -Addition of files for track reconstruction in C++ -*/ - -//__________________________________________________________________________ +/////////////////////////////////////////////////// // -// Track parameters in ALICE dimuon spectrometer -//__________________________________________________________________________ - -#include +// Track parameters +// in +// ALICE +// dimuon +// spectrometer +// +/////////////////////////////////////////////////// -#include "AliCallf77.h" -#include "AliMUON.h" -#include "AliMUONHitForRec.h" -#include "AliMUONSegment.h" +//#include +#include "AliMUON.h" #include "AliMUONTrackParam.h" -#include "AliMUONChamber.h" +#include "AliMUONConstants.h" #include "AliRun.h" +#include "AliMagF.h" +#include "AliLog.h" ClassImp(AliMUONTrackParam) // Class implementation in ROOT context -#ifndef WIN32 -# define reco_ghelix reco_ghelix_ -#else -# define reco_ghelix RECO_GHELIX -#endif - -extern "C" -{ -void type_of_call reco_ghelix(Double_t &Charge, Double_t &StepLength, Double_t *VGeant3, Double_t *VGeant3New); -} - -// Inline functions for Get and Set: inline removed because it does not work !!!! -Double_t AliMUONTrackParam::GetInverseBendingMomentum(void) { - // Get fInverseBendingMomentum - return fInverseBendingMomentum;} -void AliMUONTrackParam::SetInverseBendingMomentum(Double_t InverseBendingMomentum) { - // Set fInverseBendingMomentum - fInverseBendingMomentum = InverseBendingMomentum;} -Double_t AliMUONTrackParam::GetBendingSlope(void) { - // Get fBendingSlope - return fBendingSlope;} -void AliMUONTrackParam::SetBendingSlope(Double_t BendingSlope) { - // Set fBendingSlope - fBendingSlope = BendingSlope;} -Double_t AliMUONTrackParam::GetNonBendingSlope(void) { - // Get fNonBendingSlope - return fNonBendingSlope;} -void AliMUONTrackParam::SetNonBendingSlope(Double_t NonBendingSlope) { - // Set fNonBendingSlope - fNonBendingSlope = NonBendingSlope;} -Double_t AliMUONTrackParam::GetZ(void) { - // Get fZ - return fZ;} -void AliMUONTrackParam::SetZ(Double_t Z) { - // Set fZ - fZ = Z;} -Double_t AliMUONTrackParam::GetBendingCoor(void) { - // Get fBendingCoor - return fBendingCoor;} -void AliMUONTrackParam::SetBendingCoor(Double_t BendingCoor) { - // Set fBendingCoor - fBendingCoor = BendingCoor;} -Double_t AliMUONTrackParam::GetNonBendingCoor(void) { - // Get fNonBendingCoor - return fNonBendingCoor;} -void AliMUONTrackParam::SetNonBendingCoor(Double_t NonBendingCoor) { - // Set fNonBendingCoor - fNonBendingCoor = NonBendingCoor;} + //_________________________________________________________________________ +AliMUONTrackParam::AliMUONTrackParam() + : TObject() +{ +// Constructor + + fInverseBendingMomentum = 0; + fBendingSlope = 0; + fNonBendingSlope = 0; + fZ = 0; + fBendingCoor = 0; + fNonBendingCoor = 0; +} + + //_________________________________________________________________________ +AliMUONTrackParam& +AliMUONTrackParam::operator=(const AliMUONTrackParam& theMUONTrackParam) +{ + // Asignment operator + if (this == &theMUONTrackParam) + return *this; + + // base class assignement + TObject::operator=(theMUONTrackParam); + + fInverseBendingMomentum = theMUONTrackParam.fInverseBendingMomentum; + fBendingSlope = theMUONTrackParam.fBendingSlope; + fNonBendingSlope = theMUONTrackParam.fNonBendingSlope; + fZ = theMUONTrackParam.fZ; + fBendingCoor = theMUONTrackParam.fBendingCoor; + fNonBendingCoor = theMUONTrackParam.fNonBendingCoor; + + return *this; +} + //_________________________________________________________________________ +AliMUONTrackParam::AliMUONTrackParam(const AliMUONTrackParam& theMUONTrackParam) + : TObject(theMUONTrackParam) +{ + // Copy constructor + fInverseBendingMomentum = theMUONTrackParam.fInverseBendingMomentum; + fBendingSlope = theMUONTrackParam.fBendingSlope; + fNonBendingSlope = theMUONTrackParam.fNonBendingSlope; + fZ = theMUONTrackParam.fZ; + fBendingCoor = theMUONTrackParam.fBendingCoor; + fNonBendingCoor = theMUONTrackParam.fNonBendingCoor; +} //__________________________________________________________________________ void AliMUONTrackParam::ExtrapToZ(Double_t Z) @@ -98,66 +88,63 @@ void AliMUONTrackParam::ExtrapToZ(Double_t Z) // Track parameter extrapolation to the plane at "Z". // On return, the track parameters resulting from the extrapolation // replace the current track parameters. - // Use "reco_ghelix" which should be replaced by something else !!!! if (this->fZ == Z) return; // nothing to be done if same Z Double_t forwardBackward; // +1 if forward, -1 if backward - if (Z > this->fZ) forwardBackward = 1.0; + if (Z < this->fZ) forwardBackward = 1.0; // spectro. z<0 else forwardBackward = -1.0; - Double_t temp, vGeant3[7], vGeant3New[7]; // 7 in parameter ???? + Double_t vGeant3[7], vGeant3New[7]; // 7 in parameter ???? Int_t iGeant3, stepNumber; Int_t maxStepNumber = 5000; // in parameter ???? // For safety: return kTRUE or kFALSE ???? - // Parameter vector for calling GHELIX in Geant3 + // Parameter vector for calling EXTRAP_ONESTEP SetGeant3Parameters(vGeant3, forwardBackward); - // For use of reco_ghelix...: invert X and Y, PX/PTOT and PY/PTOT !!!! - temp = vGeant3[0]; vGeant3[0] = vGeant3[1]; vGeant3[1] = temp; - temp = vGeant3[3]; vGeant3[3] = vGeant3[4]; vGeant3[4] = temp; - // charge must be changed with momentum for backward motion - Double_t charge = - forwardBackward * TMath::Sign(Double_t(1.0), this->fInverseBendingMomentum); + // sign of charge (sign of fInverseBendingMomentum if forward motion) + // must be changed if backward extrapolation + Double_t chargeExtrap = forwardBackward * + TMath::Sign(Double_t(1.0), this->fInverseBendingMomentum); Double_t stepLength = 6.0; // in parameter ???? // Extrapolation loop stepNumber = 0; - while (((forwardBackward * (vGeant3[2] - Z)) <= 0.0) && + while (((-forwardBackward * (vGeant3[2] - Z)) <= 0.0) && // spectro. z<0 (stepNumber < maxStepNumber)) { stepNumber++; - // call Geant3 "ghelix" subroutine through a copy in "reco_muon.F": - // the true function should be called, but how ???? and remove prototyping ... - reco_ghelix(charge, stepLength, vGeant3, vGeant3New); - if ((forwardBackward * (vGeant3New[2] - Z)) > 0.0) break; // one is beyond Z + // Option for switching between helix and Runge-Kutta ???? + //ExtrapOneStepRungekutta(chargeExtrap, stepLength, vGeant3, vGeant3New); + ExtrapOneStepHelix(chargeExtrap, stepLength, vGeant3, vGeant3New); + if ((-forwardBackward * (vGeant3New[2] - Z)) > 0.0) break; // one is beyond Z spectro. z<0 // better use TArray ???? for (iGeant3 = 0; iGeant3 < 7; iGeant3++) {vGeant3[iGeant3] = vGeant3New[iGeant3];} } // check maxStepNumber ???? - // For use of reco_ghelix...: - // invert back X and Y, PX/PTOT and PY/PTOT, both for vGeant3 and vGeant3New !!!! - temp = vGeant3[0]; vGeant3[0] = vGeant3[1]; vGeant3[1] = temp; - temp = vGeant3New[0]; vGeant3New[0] = vGeant3New[1]; vGeant3New[1] = temp; - temp = vGeant3[3]; vGeant3[3] = vGeant3[4]; vGeant3[4] = temp; - temp = vGeant3New[3]; vGeant3New[3] = vGeant3New[4]; vGeant3New[4] = temp; // Interpolation back to exact Z (2nd order) // should be in function ???? using TArray ???? Double_t dZ12 = vGeant3New[2] - vGeant3[2]; // 1->2 - Double_t dZ1i = Z - vGeant3[2]; // 1-i - Double_t dZi2 = vGeant3New[2] - Z; // i->2 - Double_t xPrime = (vGeant3New[0] - vGeant3[0]) / dZ12; - Double_t xSecond = - ((vGeant3New[3] / vGeant3New[5]) - (vGeant3[3] / vGeant3[5])) / dZ12; - Double_t yPrime = (vGeant3New[1] - vGeant3[1]) / dZ12; - Double_t ySecond = - ((vGeant3New[4] / vGeant3New[5]) - (vGeant3[4] / vGeant3[5])) / dZ12; - vGeant3[0] = vGeant3[0] + xPrime * dZ1i - 0.5 * xSecond * dZ1i * dZi2; // X - vGeant3[1] = vGeant3[1] + yPrime * dZ1i - 0.5 * ySecond * dZ1i * dZi2; // Y - vGeant3[2] = Z; // Z - Double_t xPrimeI = xPrime - 0.5 * xSecond * (dZi2 - dZ1i); - Double_t yPrimeI = yPrime - 0.5 * ySecond * (dZi2 - dZ1i); - vGeant3[5] = - 1.0 / TMath::Sqrt(1.0 + xPrimeI * xPrimeI + yPrimeI * yPrimeI); // PZ/PTOT - vGeant3[3] = xPrimeI * vGeant3[5]; // PX/PTOT - vGeant3[4] = yPrimeI * vGeant3[5]; // PY/PTOT - // Track parameters from Geant3 parameters - GetFromGeant3Parameters(vGeant3, charge); + if (TMath::Abs(dZ12) > 0) { + Double_t dZ1i = Z - vGeant3[2]; // 1-i + Double_t dZi2 = vGeant3New[2] - Z; // i->2 + Double_t xPrime = (vGeant3New[0] - vGeant3[0]) / dZ12; + Double_t xSecond = + ((vGeant3New[3] / vGeant3New[5]) - (vGeant3[3] / vGeant3[5])) / dZ12; + Double_t yPrime = (vGeant3New[1] - vGeant3[1]) / dZ12; + Double_t ySecond = + ((vGeant3New[4] / vGeant3New[5]) - (vGeant3[4] / vGeant3[5])) / dZ12; + vGeant3[0] = vGeant3[0] + xPrime * dZ1i - 0.5 * xSecond * dZ1i * dZi2; // X + vGeant3[1] = vGeant3[1] + yPrime * dZ1i - 0.5 * ySecond * dZ1i * dZi2; // Y + vGeant3[2] = Z; // Z + Double_t xPrimeI = xPrime - 0.5 * xSecond * (dZi2 - dZ1i); + Double_t yPrimeI = yPrime - 0.5 * ySecond * (dZi2 - dZ1i); + // (PX, PY, PZ)/PTOT assuming forward motion + vGeant3[5] = + 1.0 / TMath::Sqrt(1.0 + xPrimeI * xPrimeI + yPrimeI * yPrimeI); // PZ/PTOT + vGeant3[3] = xPrimeI * vGeant3[5]; // PX/PTOT + vGeant3[4] = yPrimeI * vGeant3[5]; // PY/PTOT + } else { + AliWarning(Form("Extrap. to Z not reached, Z = %f",Z)); + } + // Track parameters from Geant3 parameters, + // with charge back for forward motion + GetFromGeant3Parameters(vGeant3, chargeExtrap * forwardBackward); } //__________________________________________________________________________ @@ -176,7 +163,7 @@ void AliMUONTrackParam::SetGeant3Parameters(Double_t *VGeant3, Double_t ForwardB VGeant3[6] = TMath::Sqrt(pYZ * pYZ + pZ * pZ * this->fNonBendingSlope * this->fNonBendingSlope); // PTOT - VGeant3[5] = ForwardBackward * pZ / VGeant3[6]; // PZ/PTOT + VGeant3[5] = -ForwardBackward * pZ / VGeant3[6]; // PZ/PTOT spectro. z<0 VGeant3[3] = this->fNonBendingSlope * VGeant3[5]; // PX/PTOT VGeant3[4] = this->fBendingSlope * VGeant3[5]; // PY/PTOT } @@ -185,7 +172,8 @@ void AliMUONTrackParam::SetGeant3Parameters(Double_t *VGeant3, Double_t ForwardB void AliMUONTrackParam::GetFromGeant3Parameters(Double_t *VGeant3, Double_t Charge) { // Get track parameters in current AliMUONTrackParam - // from Geant3 parameters pointed to by "VGeant3". + // from Geant3 parameters pointed to by "VGeant3", + // assumed to be calculated for forward motion in Z. // "InverseBendingMomentum" is signed with "Charge". this->fNonBendingCoor = VGeant3[0]; // X this->fBendingCoor = VGeant3[1]; // Y @@ -204,18 +192,18 @@ void AliMUONTrackParam::ExtrapToStation(Int_t Station, AliMUONTrackParam *TrackP // are returned in the array (dimension 2) of track parameters // pointed to by "TrackParam" (index 0 and 1 for first and second chambers). Double_t extZ[2], z1, z2; - Int_t i1, i2; - AliMUON *pMUON = (AliMUON*) gAlice->GetModule("MUON"); // necessary ???? + Int_t i1 = -1, i2 = -1; // = -1 to avoid compilation warnings // range of Station to be checked ???? - z1 = (&(pMUON->Chamber(2 * Station)))->Z(); // Z of first chamber - z2 = (&(pMUON->Chamber(2 * Station + 1)))->Z(); // Z of second chamber + z1 = AliMUONConstants::DefaultChamberZ(2 * Station); + z2 = AliMUONConstants::DefaultChamberZ(2 * Station + 1); // First and second Z to extrapolate at if ((z1 > this->fZ) && (z2 > this->fZ)) {i1 = 0; i2 = 1;} else if ((z1 < this->fZ) && (z2 < this->fZ)) {i1 = 1; i2 = 0;} else { - cout << "ERROR in AliMUONTrackParam::CreateExtrapSegmentInStation" << endl; - cout << "Starting Z (" << this->fZ << ") in between z1 (" << z1 << - ") and z2 (" << z2 << ") of station(0..) " << Station << endl; + AliError(Form("Starting Z (%f) in between z1 (%f) and z2 (%f) of station(0..)%d",this->fZ,z1,z2,Station)); +// cout << "ERROR in AliMUONTrackParam::CreateExtrapSegmentInStation" << endl; +// cout << "Starting Z (" << this->fZ << ") in between z1 (" << z1 << +// ") and z2 (" << z2 << ") of station(0..) " << Station << endl; } extZ[i1] = z1; extZ[i2] = z2; @@ -229,3 +217,814 @@ void AliMUONTrackParam::ExtrapToStation(Int_t Station, AliMUONTrackParam *TrackP return; } + //__________________________________________________________________________ +void AliMUONTrackParam::ExtrapToVertex(Double_t xVtx, Double_t yVtx, Double_t zVtx) +{ + // Extrapolation to the vertex. + // Returns the track parameters resulting from the extrapolation, + // in the current TrackParam. + // Changes parameters according to Branson correction through the absorber + + Double_t zAbsorber = -503.0; // to be coherent with the Geant absorber geometry !!!! + // spectro. (z<0) + // Extrapolates track parameters upstream to the "Z" end of the front absorber + ExtrapToZ(zAbsorber); // !!! + // Makes Branson correction (multiple scattering + energy loss) + BransonCorrection(xVtx,yVtx,zVtx); + // Makes a simple magnetic field correction through the absorber + FieldCorrection(zAbsorber); +} + + +// Keep this version for future developments + //__________________________________________________________________________ +// void AliMUONTrackParam::BransonCorrection() +// { +// // Branson correction of track parameters +// // the entry parameters have to be calculated at the end of the absorber +// Double_t zEndAbsorber, zBP, xBP, yBP; +// Double_t pYZ, pX, pY, pZ, pTotal, xEndAbsorber, yEndAbsorber, radiusEndAbsorber2, pT, theta; +// Int_t sign; +// // Would it be possible to calculate all that from Geant configuration ???? +// // and to get the Branson parameters from a function in ABSO module ???? +// // with an eventual contribution from other detectors like START ???? +// // Radiation lengths outer part theta > 3 degres +// static Double_t x01[9] = { 18.8, // C (cm) +// 10.397, // Concrete (cm) +// 0.56, // Plomb (cm) +// 47.26, // Polyethylene (cm) +// 0.56, // Plomb (cm) +// 47.26, // Polyethylene (cm) +// 0.56, // Plomb (cm) +// 47.26, // Polyethylene (cm) +// 0.56 }; // Plomb (cm) +// // inner part theta < 3 degres +// static Double_t x02[3] = { 18.8, // C (cm) +// 10.397, // Concrete (cm) +// 0.35 }; // W (cm) +// // z positions of the materials inside the absober outer part theta > 3 degres +// static Double_t z1[10] = { 90, 315, 467, 472, 477, 482, 487, 492, 497, 502 }; +// // inner part theta < 3 degres +// static Double_t z2[4] = { 90, 315, 467, 503 }; +// static Bool_t first = kTRUE; +// static Double_t zBP1, zBP2, rLimit; +// // Calculates z positions of the Branson's planes: zBP1 for outer part and zBP2 for inner part (only at the first call) +// if (first) { +// first = kFALSE; +// Double_t aNBP = 0.0; +// Double_t aDBP = 0.0; +// Int_t iBound; + +// for (iBound = 0; iBound < 9; iBound++) { +// aNBP = aNBP + +// (z1[iBound+1] * z1[iBound+1] * z1[iBound+1] - +// z1[iBound] * z1[iBound] * z1[iBound] ) / x01[iBound]; +// aDBP = aDBP + +// (z1[iBound+1] * z1[iBound+1] - z1[iBound] * z1[iBound] ) / x01[iBound]; +// } +// zBP1 = (2.0 * aNBP) / (3.0 * aDBP); +// aNBP = 0.0; +// aDBP = 0.0; +// for (iBound = 0; iBound < 3; iBound++) { +// aNBP = aNBP + +// (z2[iBound+1] * z2[iBound+1] * z2[iBound+1] - +// z2[iBound] * z2[iBound ] * z2[iBound] ) / x02[iBound]; +// aDBP = aDBP + +// (z2[iBound+1] * z2[iBound+1] - z2[iBound] * z2[iBound]) / x02[iBound]; +// } +// zBP2 = (2.0 * aNBP) / (3.0 * aDBP); +// rLimit = z2[3] * TMath::Tan(3.0 * (TMath::Pi()) / 180.); +// } + +// pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); +// sign = 1; +// if (fInverseBendingMomentum < 0) sign = -1; +// pZ = pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); +// pX = pZ * fNonBendingSlope; +// pY = pZ * fBendingSlope; +// pTotal = TMath::Sqrt(pYZ *pYZ + pX * pX); +// xEndAbsorber = fNonBendingCoor; +// yEndAbsorber = fBendingCoor; +// radiusEndAbsorber2 = xEndAbsorber * xEndAbsorber + yEndAbsorber * yEndAbsorber; + +// if (radiusEndAbsorber2 > rLimit*rLimit) { +// zEndAbsorber = z1[9]; +// zBP = zBP1; +// } else { +// zEndAbsorber = z2[3]; +// zBP = zBP2; +// } + +// xBP = xEndAbsorber - (pX / pZ) * (zEndAbsorber - zBP); +// yBP = yEndAbsorber - (pY / pZ) * (zEndAbsorber - zBP); + +// // new parameters after Branson and energy loss corrections +// pZ = pTotal * zBP / TMath::Sqrt(xBP * xBP + yBP * yBP + zBP * zBP); +// pX = pZ * xBP / zBP; +// pY = pZ * yBP / zBP; +// fBendingSlope = pY / pZ; +// fNonBendingSlope = pX / pZ; + +// pT = TMath::Sqrt(pX * pX + pY * pY); +// theta = TMath::ATan2(pT, pZ); +// pTotal = +// TotalMomentumEnergyLoss(rLimit, pTotal, theta, xEndAbsorber, yEndAbsorber); + +// fInverseBendingMomentum = (sign / pTotal) * +// TMath::Sqrt(1.0 + +// fBendingSlope * fBendingSlope + +// fNonBendingSlope * fNonBendingSlope) / +// TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope); + +// // vertex position at (0,0,0) +// // should be taken from vertex measurement ??? +// fBendingCoor = 0.0; +// fNonBendingCoor = 0; +// fZ= 0; +// } + +void AliMUONTrackParam::BransonCorrection(Double_t xVtx,Double_t yVtx,Double_t zVtx) +{ + // Branson correction of track parameters + // the entry parameters have to be calculated at the end of the absorber + // simplified version: the z positions of Branson's planes are no longer calculated + // but are given as inputs. One can use the macros MUONTestAbso.C and DrawTestAbso.C + // to test this correction. + // Would it be possible to calculate all that from Geant configuration ???? + // and to get the Branson parameters from a function in ABSO module ???? + // with an eventual contribution from other detectors like START ???? + //change to take into account the vertex postition (real, reconstruct,....) + + Double_t zBP, xBP, yBP; + Double_t pYZ, pX, pY, pZ, pTotal, xEndAbsorber, yEndAbsorber, radiusEndAbsorber2, pT, theta; + Int_t sign; + static Bool_t first = kTRUE; + static Double_t zBP1, zBP2, rLimit, thetaLimit, zEndAbsorber; + // zBP1 for outer part and zBP2 for inner part (only at the first call) + if (first) { + first = kFALSE; + + zEndAbsorber = -503; // spectro (z<0) + thetaLimit = 3.0 * (TMath::Pi()) / 180.; + rLimit = TMath::Abs(zEndAbsorber) * TMath::Tan(thetaLimit); + zBP1 = -450; // values close to those calculated with EvalAbso.C + zBP2 = -480; + } + + pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); + sign = 1; + if (fInverseBendingMomentum < 0) sign = -1; + pZ = Pz(); + pX = Px(); + pY = Py(); + pTotal = TMath::Sqrt(pYZ *pYZ + pX * pX); + xEndAbsorber = fNonBendingCoor; + yEndAbsorber = fBendingCoor; + radiusEndAbsorber2 = xEndAbsorber * xEndAbsorber + yEndAbsorber * yEndAbsorber; + + if (radiusEndAbsorber2 > rLimit*rLimit) { + zBP = zBP1; + } else { + zBP = zBP2; + } + + xBP = xEndAbsorber - (pX / pZ) * (zEndAbsorber - zBP); + yBP = yEndAbsorber - (pY / pZ) * (zEndAbsorber - zBP); + + // new parameters after Branson and energy loss corrections +// Float_t zSmear = zBP - gRandom->Gaus(0.,2.); // !!! possible smearing of Z vertex position + + Float_t zSmear = zBP ; + + pZ = pTotal * (zSmear-zVtx) / TMath::Sqrt((xBP-xVtx) * (xBP-xVtx) + (yBP-yVtx) * (yBP-yVtx) +( zSmear-zVtx) * (zSmear-zVtx) ); + pX = pZ * (xBP - xVtx)/ (zSmear-zVtx); + pY = pZ * (yBP - yVtx) / (zSmear-zVtx); + fBendingSlope = pY / pZ; + fNonBendingSlope = pX / pZ; + + + pT = TMath::Sqrt(pX * pX + pY * pY); + theta = TMath::ATan2(pT, TMath::Abs(pZ)); + pTotal = TotalMomentumEnergyLoss(thetaLimit, pTotal, theta); + + fInverseBendingMomentum = (sign / pTotal) * + TMath::Sqrt(1.0 + + fBendingSlope * fBendingSlope + + fNonBendingSlope * fNonBendingSlope) / + TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope); + + // vertex position at (0,0,0) + // should be taken from vertex measurement ??? + + fBendingCoor = xVtx; + fNonBendingCoor = yVtx; + fZ= zVtx; + +} + + //__________________________________________________________________________ +Double_t AliMUONTrackParam::TotalMomentumEnergyLoss(Double_t thetaLimit, Double_t pTotal, Double_t theta) +{ + // Returns the total momentum corrected from energy loss in the front absorber + // One can use the macros MUONTestAbso.C and DrawTestAbso.C + // to test this correction. + // Momentum energy loss behaviour evaluated with the simulation of single muons (april 2002) + Double_t deltaP, pTotalCorrected; + + // Parametrization to be redone according to change of absorber material ???? + // See remark in function BransonCorrection !!!! + // The name is not so good, and there are many arguments !!!! + if (theta < thetaLimit ) { + if (pTotal < 20) { + deltaP = 2.5938 + 0.0570 * pTotal - 0.001151 * pTotal * pTotal; + } else { + deltaP = 3.0714 + 0.011767 *pTotal; + } + deltaP *= 0.75; // AZ + } else { + if (pTotal < 20) { + deltaP = 2.1207 + 0.05478 * pTotal - 0.00145079 * pTotal * pTotal; + } else { + deltaP = 2.6069 + 0.0051705 * pTotal; + } + deltaP *= 0.9; // AZ + } + pTotalCorrected = pTotal + deltaP / TMath::Cos(theta); + return pTotalCorrected; +} + + //__________________________________________________________________________ +void AliMUONTrackParam::FieldCorrection(Double_t Z) +{ + // + // Correction of the effect of the magnetic field in the absorber + // Assume a constant field along Z axis. + + Float_t b[3],x[3]; + Double_t bZ; + Double_t pYZ,pX,pY,pZ,pT; + Double_t pXNew,pYNew; + Double_t c; + + pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); + c = TMath::Sign(1.0,fInverseBendingMomentum); // particle charge + + pZ = Pz(); + pX = Px(); + pY = Py(); + pT = TMath::Sqrt(pX*pX+pY*pY); + + if (TMath::Abs(pZ) <= 0) return; + x[2] = Z/2; + x[0] = x[2]*fNonBendingSlope; + x[1] = x[2]*fBendingSlope; + + // Take magn. field value at position x. + gAlice->Field()->Field(x, b); + bZ = b[2]; + + // Transverse momentum rotation + // Parameterized with the study of DeltaPhi = phiReco - phiGen as a function of pZ. + Double_t phiShift = c*0.436*0.0003*bZ*Z/pZ; + // Rotate momentum around Z axis. + pXNew = pX*TMath::Cos(phiShift) - pY*TMath::Sin(phiShift); + pYNew = pX*TMath::Sin(phiShift) + pY*TMath::Cos(phiShift); + + fBendingSlope = pYNew / pZ; + fNonBendingSlope = pXNew / pZ; + + fInverseBendingMomentum = c / TMath::Sqrt(pYNew*pYNew+pZ*pZ); + +} + //__________________________________________________________________________ +Double_t AliMUONTrackParam::Px() const +{ + // return px from track paramaters + Double_t pYZ, pZ, pX; + pYZ = 0; + if ( TMath::Abs(fInverseBendingMomentum) > 0 ) + pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); + pZ = -pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); // spectro. (z<0) + pX = pZ * fNonBendingSlope; + return pX; +} + //__________________________________________________________________________ +Double_t AliMUONTrackParam::Py() const +{ + // return px from track paramaters + Double_t pYZ, pZ, pY; + pYZ = 0; + if ( TMath::Abs(fInverseBendingMomentum) > 0 ) + pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); + pZ = -pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); // spectro. (z<0) + pY = pZ * fBendingSlope; + return pY; +} + //__________________________________________________________________________ +Double_t AliMUONTrackParam::Pz() const +{ + // return px from track paramaters + Double_t pYZ, pZ; + pYZ = 0; + if ( TMath::Abs(fInverseBendingMomentum) > 0 ) + pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); + pZ = -pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); // spectro. (z<0) + return pZ; +} + //__________________________________________________________________________ +Double_t AliMUONTrackParam::P() const +{ + // return p from track paramaters + Double_t pYZ, pZ, p; + pYZ = 0; + if ( TMath::Abs(fInverseBendingMomentum) > 0 ) + pYZ = TMath::Abs(1.0 / fInverseBendingMomentum); + pZ = -pYZ / (TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope)); // spectro. (z<0) + p = TMath::Abs(pZ) * + TMath::Sqrt(1.0 + fBendingSlope * fBendingSlope + fNonBendingSlope * fNonBendingSlope); + return p; + +} + //__________________________________________________________________________ +void AliMUONTrackParam::ExtrapOneStepHelix(Double_t charge, Double_t step, + Double_t *vect, Double_t *vout) const +{ +// ****************************************************************** +// * * +// * Performs the tracking of one step in a magnetic field * +// * The trajectory is assumed to be a helix in a constant field * +// * taken at the mid point of the step. * +// * Parameters: * +// * input * +// * STEP =arc length of the step asked * +// * VECT =input vector (position,direction cos and momentum) * +// * CHARGE= electric charge of the particle * +// * output * +// * VOUT = same as VECT after completion of the step * +// * * +// * ==>Called by : , GUSWIM * +// * Author m.hansroul ********* * +// * modified s.egli, s.v.levonian * +// * modified v.perevoztchikov +// * * +// ****************************************************************** +// + +// modif: everything in double precision + + Double_t xyz[3], h[4], hxp[3]; + Double_t h2xy, hp, rho, tet; + Double_t sint, sintt, tsint, cos1t; + Double_t f1, f2, f3, f4, f5, f6; + + const Int_t kix = 0; + const Int_t kiy = 1; + const Int_t kiz = 2; + const Int_t kipx = 3; + const Int_t kipy = 4; + const Int_t kipz = 5; + const Int_t kipp = 6; + + const Double_t kec = 2.9979251e-4; + // + // ------------------------------------------------------------------ + // + // units are kgauss,centimeters,gev/c + // + vout[kipp] = vect[kipp]; + if (TMath::Abs(charge) < 0.00001) { + for (Int_t i = 0; i < 3; i++) { + vout[i] = vect[i] + step * vect[i+3]; + vout[i+3] = vect[i+3]; + } + return; + } + xyz[0] = vect[kix] + 0.5 * step * vect[kipx]; + xyz[1] = vect[kiy] + 0.5 * step * vect[kipy]; + xyz[2] = vect[kiz] + 0.5 * step * vect[kipz]; + + //cmodif: call gufld (xyz, h) changed into: + GetField (xyz, h); + + h2xy = h[0]*h[0] + h[1]*h[1]; + h[3] = h[2]*h[2]+ h2xy; + if (h[3] < 1.e-12) { + for (Int_t i = 0; i < 3; i++) { + vout[i] = vect[i] + step * vect[i+3]; + vout[i+3] = vect[i+3]; + } + return; + } + if (h2xy < 1.e-12*h[3]) { + ExtrapOneStepHelix3(charge*h[2], step, vect, vout); + return; + } + h[3] = TMath::Sqrt(h[3]); + h[0] /= h[3]; + h[1] /= h[3]; + h[2] /= h[3]; + h[3] *= kec; + + hxp[0] = h[1]*vect[kipz] - h[2]*vect[kipy]; + hxp[1] = h[2]*vect[kipx] - h[0]*vect[kipz]; + hxp[2] = h[0]*vect[kipy] - h[1]*vect[kipx]; + + hp = h[0]*vect[kipx] + h[1]*vect[kipy] + h[2]*vect[kipz]; + + rho = -charge*h[3]/vect[kipp]; + tet = rho * step; + + if (TMath::Abs(tet) > 0.15) { + sint = TMath::Sin(tet); + sintt = (sint/tet); + tsint = (tet-sint)/tet; + cos1t = 2.*(TMath::Sin(0.5*tet))*(TMath::Sin(0.5*tet))/tet; + } else { + tsint = tet*tet/36.; + sintt = (1. - tsint); + sint = tet*sintt; + cos1t = 0.5*tet; + } + + f1 = step * sintt; + f2 = step * cos1t; + f3 = step * tsint * hp; + f4 = -tet*cos1t; + f5 = sint; + f6 = tet * cos1t * hp; + + vout[kix] = vect[kix] + f1*vect[kipx] + f2*hxp[0] + f3*h[0]; + vout[kiy] = vect[kiy] + f1*vect[kipy] + f2*hxp[1] + f3*h[1]; + vout[kiz] = vect[kiz] + f1*vect[kipz] + f2*hxp[2] + f3*h[2]; + + vout[kipx] = vect[kipx] + f4*vect[kipx] + f5*hxp[0] + f6*h[0]; + vout[kipy] = vect[kipy] + f4*vect[kipy] + f5*hxp[1] + f6*h[1]; + vout[kipz] = vect[kipz] + f4*vect[kipz] + f5*hxp[2] + f6*h[2]; + + return; +} + + //__________________________________________________________________________ +void AliMUONTrackParam::ExtrapOneStepHelix3(Double_t field, Double_t step, + Double_t *vect, Double_t *vout) const +{ +// +// ****************************************************************** +// * * +// * Tracking routine in a constant field oriented * +// * along axis 3 * +// * Tracking is performed with a conventional * +// * helix step method * +// * * +// * ==>Called by : , GUSWIM * +// * Authors R.Brun, M.Hansroul ********* * +// * Rewritten V.Perevoztchikov +// * * +// ****************************************************************** +// + + Double_t hxp[3]; + Double_t h4, hp, rho, tet; + Double_t sint, sintt, tsint, cos1t; + Double_t f1, f2, f3, f4, f5, f6; + + const Int_t kix = 0; + const Int_t kiy = 1; + const Int_t kiz = 2; + const Int_t kipx = 3; + const Int_t kipy = 4; + const Int_t kipz = 5; + const Int_t kipp = 6; + + const Double_t kec = 2.9979251e-4; + +// +// ------------------------------------------------------------------ +// +// units are kgauss,centimeters,gev/c +// + vout[kipp] = vect[kipp]; + h4 = field * kec; + + hxp[0] = - vect[kipy]; + hxp[1] = + vect[kipx]; + + hp = vect[kipz]; + + rho = -h4/vect[kipp]; + tet = rho * step; + if (TMath::Abs(tet) > 0.15) { + sint = TMath::Sin(tet); + sintt = (sint/tet); + tsint = (tet-sint)/tet; + cos1t = 2.* TMath::Sin(0.5*tet) * TMath::Sin(0.5*tet)/tet; + } else { + tsint = tet*tet/36.; + sintt = (1. - tsint); + sint = tet*sintt; + cos1t = 0.5*tet; + } + + f1 = step * sintt; + f2 = step * cos1t; + f3 = step * tsint * hp; + f4 = -tet*cos1t; + f5 = sint; + f6 = tet * cos1t * hp; + + vout[kix] = vect[kix] + f1*vect[kipx] + f2*hxp[0]; + vout[kiy] = vect[kiy] + f1*vect[kipy] + f2*hxp[1]; + vout[kiz] = vect[kiz] + f1*vect[kipz] + f3; + + vout[kipx] = vect[kipx] + f4*vect[kipx] + f5*hxp[0]; + vout[kipy] = vect[kipy] + f4*vect[kipy] + f5*hxp[1]; + vout[kipz] = vect[kipz] + f4*vect[kipz] + f6; + + return; +} + //__________________________________________________________________________ +void AliMUONTrackParam::ExtrapOneStepRungekutta(Double_t charge, Double_t step, + Double_t* vect, Double_t* vout) const +{ +// +// ****************************************************************** +// * * +// * Runge-Kutta method for tracking a particle through a magnetic * +// * field. Uses Nystroem algorithm (See Handbook Nat. Bur. of * +// * Standards, procedure 25.5.20) * +// * * +// * Input parameters * +// * CHARGE Particle charge * +// * STEP Step size * +// * VECT Initial co-ords,direction cosines,momentum * +// * Output parameters * +// * VOUT Output co-ords,direction cosines,momentum * +// * User routine called * +// * CALL GUFLD(X,F) * +// * * +// * ==>Called by : , GUSWIM * +// * Authors R.Brun, M.Hansroul ********* * +// * V.Perevoztchikov (CUT STEP implementation) * +// * * +// * * +// ****************************************************************** +// + + Double_t h2, h4, f[4]; + Double_t xyzt[3], a, b, c, ph,ph2; + Double_t secxs[4],secys[4],seczs[4],hxp[3]; + Double_t g1, g2, g3, g4, g5, g6, ang2, dxt, dyt, dzt; + Double_t est, at, bt, ct, cba; + Double_t f1, f2, f3, f4, rho, tet, hnorm, hp, rho1, sint, cost; + + Double_t x; + Double_t y; + Double_t z; + + Double_t xt; + Double_t yt; + Double_t zt; + + Double_t maxit = 1992; + Double_t maxcut = 11; + + const Double_t kdlt = 1e-4; + const Double_t kdlt32 = kdlt/32.; + const Double_t kthird = 1./3.; + const Double_t khalf = 0.5; + const Double_t kec = 2.9979251e-4; + + const Double_t kpisqua = 9.86960440109; + const Int_t kix = 0; + const Int_t kiy = 1; + const Int_t kiz = 2; + const Int_t kipx = 3; + const Int_t kipy = 4; + const Int_t kipz = 5; + + // *. + // *. ------------------------------------------------------------------ + // *. + // * this constant is for units cm,gev/c and kgauss + // * + Int_t iter = 0; + Int_t ncut = 0; + for(Int_t j = 0; j < 7; j++) + vout[j] = vect[j]; + + Double_t pinv = kec * charge / vect[6]; + Double_t tl = 0.; + Double_t h = step; + Double_t rest; + + + do { + rest = step - tl; + if (TMath::Abs(h) > TMath::Abs(rest)) h = rest; + //cmodif: call gufld(vout,f) changed into: + + GetField(vout,f); + + // * + // * start of integration + // * + x = vout[0]; + y = vout[1]; + z = vout[2]; + a = vout[3]; + b = vout[4]; + c = vout[5]; + + h2 = khalf * h; + h4 = khalf * h2; + ph = pinv * h; + ph2 = khalf * ph; + secxs[0] = (b * f[2] - c * f[1]) * ph2; + secys[0] = (c * f[0] - a * f[2]) * ph2; + seczs[0] = (a * f[1] - b * f[0]) * ph2; + ang2 = (secxs[0]*secxs[0] + secys[0]*secys[0] + seczs[0]*seczs[0]); + if (ang2 > kpisqua) break; + + dxt = h2 * a + h4 * secxs[0]; + dyt = h2 * b + h4 * secys[0]; + dzt = h2 * c + h4 * seczs[0]; + xt = x + dxt; + yt = y + dyt; + zt = z + dzt; + // * + // * second intermediate point + // * + + est = TMath::Abs(dxt) + TMath::Abs(dyt) + TMath::Abs(dzt); + if (est > h) { + if (ncut++ > maxcut) break; + h *= khalf; + continue; + } + + xyzt[0] = xt; + xyzt[1] = yt; + xyzt[2] = zt; + + //cmodif: call gufld(xyzt,f) changed into: + GetField(xyzt,f); + + at = a + secxs[0]; + bt = b + secys[0]; + ct = c + seczs[0]; + + secxs[1] = (bt * f[2] - ct * f[1]) * ph2; + secys[1] = (ct * f[0] - at * f[2]) * ph2; + seczs[1] = (at * f[1] - bt * f[0]) * ph2; + at = a + secxs[1]; + bt = b + secys[1]; + ct = c + seczs[1]; + secxs[2] = (bt * f[2] - ct * f[1]) * ph2; + secys[2] = (ct * f[0] - at * f[2]) * ph2; + seczs[2] = (at * f[1] - bt * f[0]) * ph2; + dxt = h * (a + secxs[2]); + dyt = h * (b + secys[2]); + dzt = h * (c + seczs[2]); + xt = x + dxt; + yt = y + dyt; + zt = z + dzt; + at = a + 2.*secxs[2]; + bt = b + 2.*secys[2]; + ct = c + 2.*seczs[2]; + + est = TMath::Abs(dxt)+TMath::Abs(dyt)+TMath::Abs(dzt); + if (est > 2.*TMath::Abs(h)) { + if (ncut++ > maxcut) break; + h *= khalf; + continue; + } + + xyzt[0] = xt; + xyzt[1] = yt; + xyzt[2] = zt; + + //cmodif: call gufld(xyzt,f) changed into: + GetField(xyzt,f); + + z = z + (c + (seczs[0] + seczs[1] + seczs[2]) * kthird) * h; + y = y + (b + (secys[0] + secys[1] + secys[2]) * kthird) * h; + x = x + (a + (secxs[0] + secxs[1] + secxs[2]) * kthird) * h; + + secxs[3] = (bt*f[2] - ct*f[1])* ph2; + secys[3] = (ct*f[0] - at*f[2])* ph2; + seczs[3] = (at*f[1] - bt*f[0])* ph2; + a = a+(secxs[0]+secxs[3]+2. * (secxs[1]+secxs[2])) * kthird; + b = b+(secys[0]+secys[3]+2. * (secys[1]+secys[2])) * kthird; + c = c+(seczs[0]+seczs[3]+2. * (seczs[1]+seczs[2])) * kthird; + + est = TMath::Abs(secxs[0]+secxs[3] - (secxs[1]+secxs[2])) + + TMath::Abs(secys[0]+secys[3] - (secys[1]+secys[2])) + + TMath::Abs(seczs[0]+seczs[3] - (seczs[1]+seczs[2])); + + if (est > kdlt && TMath::Abs(h) > 1.e-4) { + if (ncut++ > maxcut) break; + h *= khalf; + continue; + } + + ncut = 0; + // * if too many iterations, go to helix + if (iter++ > maxit) break; + + tl += h; + if (est < kdlt32) + h *= 2.; + cba = 1./ TMath::Sqrt(a*a + b*b + c*c); + vout[0] = x; + vout[1] = y; + vout[2] = z; + vout[3] = cba*a; + vout[4] = cba*b; + vout[5] = cba*c; + rest = step - tl; + if (step < 0.) rest = -rest; + if (rest < 1.e-5*TMath::Abs(step)) return; + + } while(1); + + // angle too big, use helix + + f1 = f[0]; + f2 = f[1]; + f3 = f[2]; + f4 = TMath::Sqrt(f1*f1+f2*f2+f3*f3); + rho = -f4*pinv; + tet = rho * step; + + hnorm = 1./f4; + f1 = f1*hnorm; + f2 = f2*hnorm; + f3 = f3*hnorm; + + hxp[0] = f2*vect[kipz] - f3*vect[kipy]; + hxp[1] = f3*vect[kipx] - f1*vect[kipz]; + hxp[2] = f1*vect[kipy] - f2*vect[kipx]; + + hp = f1*vect[kipx] + f2*vect[kipy] + f3*vect[kipz]; + + rho1 = 1./rho; + sint = TMath::Sin(tet); + cost = 2.*TMath::Sin(khalf*tet)*TMath::Sin(khalf*tet); + + g1 = sint*rho1; + g2 = cost*rho1; + g3 = (tet-sint) * hp*rho1; + g4 = -cost; + g5 = sint; + g6 = cost * hp; + + vout[kix] = vect[kix] + g1*vect[kipx] + g2*hxp[0] + g3*f1; + vout[kiy] = vect[kiy] + g1*vect[kipy] + g2*hxp[1] + g3*f2; + vout[kiz] = vect[kiz] + g1*vect[kipz] + g2*hxp[2] + g3*f3; + + vout[kipx] = vect[kipx] + g4*vect[kipx] + g5*hxp[0] + g6*f1; + vout[kipy] = vect[kipy] + g4*vect[kipy] + g5*hxp[1] + g6*f2; + vout[kipz] = vect[kipz] + g4*vect[kipz] + g5*hxp[2] + g6*f3; + + return; +} +//___________________________________________________________ + void AliMUONTrackParam::GetField(Double_t *Position, Double_t *Field) const +{ + // interface to "gAlice->Field()->Field" for arguments in double precision + + Float_t x[3], b[3]; + + x[0] = Position[0]; x[1] = Position[1]; x[2] = Position[2]; + + gAlice->Field()->Field(x, b); + Field[0] = b[0]; Field[1] = b[1]; Field[2] = b[2]; + + return; + } +//_____________________________________________- +void AliMUONTrackParam::Print(Option_t* opt) const +{ +// + // Printing TrackParam information + // "full" option for printing all the information about the TrackParam + // + TString sopt(opt); + sopt.ToUpper(); + + if ( sopt.Contains("FULL") ) { + cout << " Bending P=" << setw(5) << setprecision(3) << 1./GetInverseBendingMomentum() << + ", NonBendSlope=" << setw(5) << setprecision(3) << GetNonBendingSlope()*180./TMath::Pi() << + ", BendSlope=" << setw(5) << setprecision(3) << GetBendingSlope()*180./TMath::Pi() << + ", (x,y,z)_IP=(" << setw(5) << setprecision(3) << GetNonBendingCoor() << + "," << setw(5) << setprecision(3) << GetBendingCoor() << + "," << setw(5) << setprecision(3) << GetZ() << + ") cm, (px,py,pz)=(" << setw(5) << setprecision(3) << Px() << + "," << setw(5) << setprecision(3) << Py() << + "," << setw(5) << setprecision(3) << Pz() << ") GeV/c" << endl; + } + else { + cout << "" << endl; + } + +}