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//==================================================================================================
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// $Id $
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//
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// Description: class TrackParameters
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//
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// Class to manage track parameters of different conventions and convert one into the other. This is
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// not really done very well and could be done more efficient but this is what it is for the moment.
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//
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// Original Author: Christoph Paus
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// Created: Thu Aug 21 02:29:00 CEST 2008
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//
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// -------------------------------------------------------------------------------------------------
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// CMS parameter ordering for the vector/matrix, which is assumed here:
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//
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// qoverp, lambda, phi0, dxy, dsz; (lambda = pi/2 - theta)
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// mapping to CDF is therefore { 1*, 0*, 4, 3, 2* }, where * indicates that a transformation is
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// needed
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//
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// Note that the radius of curvature (in cm) is then:
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//
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// Rc = cos(theta) / [ 0.0029979.... * (q/p) * B ],
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//
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// where B is the magnetic field in Tesla and tht is the angle between the field and the
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// direction. With p * cos(theta) = pT it follows:
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//
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// Rc = pT / [ 0.0029979.... * q * B ],
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// fullCurvature = 1 / Rc = 0.0029979 * q * B / pT = - 0.0029979 * B / pT.
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//
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// see the conventions for the MultiVertexFitter in its own header file.
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//==================================================================================================
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#ifndef _VERTEXFITINTERFACE_TRACKPARAMETERS_H_
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#define _VERTEXFITINTERFACE_TRACKPARAMETERS_H_
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#include "TMatrixDSym.h"
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#include "TVectorD.h"
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#include "DataFormats/TrackReco/interface/Track.h"
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namespace mitedm
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{
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// Define existing track parameter conventions
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enum TrackConvention { iCms, iMvf };
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// Declare the track parameter class
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class TrackParameters
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{
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public:
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// *structors
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TrackParameters() {}
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TrackParameters(const reco::Track *trk, TrackConvention tcv = iCms, double bField = 3.8);
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TrackParameters(const TrackParameters &trk);
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~TrackParameters() {};
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// Access the specific contents
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const TVectorD *pars () const { return &pars_; };
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double pars (int i) const { return pars_[i]; };
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const TMatrixDSym *cMat () const { return &cMat_; };
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double cMat (int i, int j) const { return cMat_(i,j); };
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// Access the different parametrizations independently of the local storage
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TrackParameters cmsTrack() const;
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TrackParameters mvfTrack() const;
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void setPars (int i, double v) { pars_(i) = v; }
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void setCMat (int i, int j, double v) { cMat_(i,j) = v; }
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void addCMat (int i, int j, double v) { cMat_(i,j) += v; }
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// Utilities
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void print () const;
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private:
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TrackConvention iConvention_; // track parameter convention (def. CMS)
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double bField_; // magnetic field in Tesla
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double fCurv_; // combined curvature constant
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TVectorD pars_; // track paramters (helix)
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TMatrixDSym cMat_; // corresponding covariance matrix (sig_i * sig_j)
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};
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}
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#endif
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