SurfLine.h File Reference

Base class for Kalman filter line surfaces. More...

#include <ostream>
#include "lardata/RecoObjects/Surface.h"

Go to the source code of this file.

Classes
class	trkf::SurfLine

Namespaces
	trkf

Detailed Description

Base class for Kalman filter line surfaces.

Author

H. Greenlee

This class acts as an intermediate layer between abstract surfaces (base class Surface), and concrete line surfaces (like SurfYZLine). It does not include any data members of its own. It guarantees the existence of a right-handed local Cartesian coordinate system (u,v,w), in which this line surface corresponds to the v-axis. A track is considered to be at this type of surface when it is at its closest approach to the v-axis.

Track parameters on this type of surface are:

1. r
2. v
3. phi
4. eta
5. 1/p (nonmagnetic) or q/p (magnetic)

r = Signed impoact parameter. Absolute value of r is the perpendicular distance of the track to the v-axis at the point of closest approach to v-axis. Sign of r matches sign of L_v (v projection of angular momentum). v = V-coordinate of track at point of closest approach to v-axis. phi = Direction of track in u-w plane (phi = arctan(w/u)). eta = Pseudorapidity with respect to v-axis. q/p or 1/p = Inverse momentum.

In terms of these parameters, the point of closest approach to the v-axis is

u = -r sin(phi) v = v w = r cos(phi)

The unit direction vector is

du/ds = cos(phi) sech(eta) dv/ds = tanh(eta) dw/ds = sin(phi) sech(eta)

Definition in file SurfLine.h.