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TrajectoryStateAccessor Class Reference

#include <TrajectoryStateAccessor.h>

Public Member Functions

float inversePtError () const
 
 TrajectoryStateAccessor (const FreeTrajectoryState &fts)
 

Private Attributes

const FreeTrajectoryStatetheFts
 

Detailed Description

Helper class to obtain the uncertainty on specific trajectory parameters.

Definition at line 10 of file TrajectoryStateAccessor.h.

Constructor & Destructor Documentation

◆ TrajectoryStateAccessor()

TrajectoryStateAccessor::TrajectoryStateAccessor ( const FreeTrajectoryState fts)
inline

Definition at line 12 of file TrajectoryStateAccessor.h.

12 : theFts(fts) {}
const FreeTrajectoryState & theFts

Member Function Documentation

◆ inversePtError()

float TrajectoryStateAccessor::inversePtError ( ) const

Definition at line 5 of file TrajectoryStateAccessor.cc.

References alignCSCRings::corr, FreeTrajectoryState::curvilinearError(), CurvilinearTrajectoryError::matrix(), FreeTrajectoryState::momentum(), pfMETCorrectionType0_cfi::par2, PV3DBase< T, PVType, FrameType >::perp2(), mathSSE::sqrt(), theFts, and PV3DBase< T, PVType, FrameType >::z().

Referenced by ThresholdPtTrajectoryFilter::test().

5  {
6  GlobalVector momentum = theFts.momentum();
7  AlgebraicSymMatrix55 const& errMatrix = theFts.curvilinearError().matrix();
8 
9  float ptRec2 = momentum.perp2();
10  float pzRec = momentum.z();
11  float pzRec2 = pzRec * pzRec;
12  float CosTheta2 = (pzRec2) / (ptRec2 + pzRec2);
13  float SinTheta2 = 1.f - CosTheta2;
14 
15  float par2 = CosTheta2 / ptRec2;
16 
17  float InvpErr = errMatrix(0, 0);
18  float thetaErr = errMatrix(1, 1);
19  float corr = errMatrix(0, 1);
20 
21  float invPtErr2 = (InvpErr + par2 * thetaErr - 2.f * std::sqrt(par2) * corr) / (SinTheta2);
22  return std::sqrt(invPtErr2);
23 }
const FreeTrajectoryState & theFts
const CurvilinearTrajectoryError & curvilinearError() const
T z() const
Definition: PV3DBase.h:61
dictionary corr
T sqrt(T t)
Definition: SSEVec.h:19
GlobalVector momentum() const
const AlgebraicSymMatrix55 & matrix() const
ROOT::Math::SMatrix< double, 5, 5, ROOT::Math::MatRepSym< double, 5 > > AlgebraicSymMatrix55
T perp2() const
Definition: PV3DBase.h:68

Member Data Documentation

◆ theFts

const FreeTrajectoryState& TrajectoryStateAccessor::theFts
private

Definition at line 17 of file TrajectoryStateAccessor.h.

Referenced by inversePtError().