SurfYZLine.h File Reference

Line surface perpendicular to x-axis. More...

#include "lardata/RecoObjects/SurfLine.h"

Go to the source code of this file.

Classes
class	trkf::SurfYZLine

Namespaces
	trkf

Detailed Description

Line surface perpendicular to x-axis.

Author

H. Greenlee

This class represents a line surface perpendicular to the global x-axis, or equivalently, parallel to the yz-plane.

The surface parameters and local coordinate system of this surface are the same as SurfYZPlane.

This surface is defined by four parameters, which are, (x0, y0, z0) - Local origin in global coordinates. phi - Rotation angle around x-axis.

The local uvw coordinate system is related to the global xyz coordinate system as follows.

u = x-x0 v = (y-y0)*cos(phi) + (z-z0)*sin(phi) w = -(y-y0)*sin(phi) + (z-z0)*cos(phi)

or inversely,

x = x0 + u y = y0 + v*cos(phi) - w*sin(phi) z = z0 + v*sin(phi) + w*cos(phi)

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)

Inversely:

phi = atan(dw/du) = atan2(dw/ds, du/ds) eta = atanh(dv/ds) = asinh(dv/duw) r = w cos(phi) - u sin(phi)

Definition in file SurfYZLine.h.