FourHitVariables.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
#pragma once
 
#include <tracking/vxdHoughTracking/filters/pathFilters/ThreeHitVariables.h>
#include <tracking/spacePointCreation/SpacePoint.h>
#include <framework/geometry/B2Vector3.h>
 
#include <cmath>
 
namespace Belle2 {
  namespace vxdHoughTracking {

    class FourHitVariables {
    public:
      FourHitVariables() : m_oHit(0., 0., 0.), m_ocHit(0., 0., 0.), m_icHit(0., 0., 0.), m_iHit(0., 0., 0.)
      {};

      FourHitVariables(const B2Vector3D& oHit, const B2Vector3D& ocHit, const B2Vector3D& icHit, const B2Vector3D& iHit) :
        m_oHit(oHit), m_ocHit(ocHit), m_icHit(icHit), m_iHit(iHit)
      {
        m_outerThreeHitVariables = ThreeHitVariables(oHit, ocHit, icHit);
        m_innerThreeHitVariables = ThreeHitVariables(ocHit, icHit, iHit);
      };

      void setHits(const B2Vector3D& oHit, const B2Vector3D& ocHit, const B2Vector3D& icHit, const B2Vector3D& iHit)
      {
        m_oHit = oHit;
        m_ocHit = ocHit;
        m_icHit = icHit;
        m_iHit = iHit;
        m_outerThreeHitVariables = ThreeHitVariables(oHit, ocHit, icHit);
        m_innerThreeHitVariables = ThreeHitVariables(ocHit, icHit, iHit);
      }

      double getCircleRadiusDifference()
      {
        B2Vector3D outerCircleCenter = m_outerThreeHitVariables.getCircleCenterXY();
        B2Vector3D innerCircleCenter = m_innerThreeHitVariables.getCircleCenterXY();
        if (outerCircleCenter.Perp2() > 1e30 or innerCircleCenter.Perp2() > 1e30) {
          return NAN;
        }
        double outerCircleRadius = m_outerThreeHitVariables.calcAvgDistanceXY(outerCircleCenter);
        double innerCircleRadius = m_innerThreeHitVariables.calcAvgDistanceXY(innerCircleCenter);
 
        return outerCircleRadius - innerCircleRadius;
      }
 

      double getCircleCenterPositionDifference()
      {
        B2Vector3D outerCircleCenter = m_outerThreeHitVariables.getCircleCenterXY();
        B2Vector3D innerCircleCenter = m_innerThreeHitVariables.getCircleCenterXY();
        if (outerCircleCenter.Perp2() > 1e30 or innerCircleCenter.Perp2() > 1e30) {
          return NAN;
        }
 
        return fabs(outerCircleCenter.Perp() - innerCircleCenter.Perp());
      }
 

      double getDeltaPT()
      {
        B2Vector3D outerCircleCenter = m_outerThreeHitVariables.getCircleCenterXY();
        B2Vector3D innerCircleCenter = m_innerThreeHitVariables.getCircleCenterXY();
        if (outerCircleCenter.Perp2() > 1e30 or innerCircleCenter.Perp2() > 1e30) {
          return NAN;
        }
        double outerCircleRadius = m_outerThreeHitVariables.calcAvgDistanceXY(outerCircleCenter);
        double innerCircleRadius = m_innerThreeHitVariables.calcAvgDistanceXY(innerCircleCenter);
 
        return fabs(0.00299792458 * m_BFieldZ * (outerCircleRadius - innerCircleRadius));
      }

      void setBFieldZ(const double bfieldZ = 1.5) { m_BFieldZ = bfieldZ; }
 
    private:
      ThreeHitVariables m_outerThreeHitVariables;
      ThreeHitVariables m_innerThreeHitVariables;
      B2Vector3D m_oHit;
      B2Vector3D m_ocHit;
      B2Vector3D m_icHit;
      B2Vector3D m_iHit;
      double m_BFieldZ = 1.5;
 
    };
 
  }
}