The formulae used to estimate transverse are taken from the Particle
Data Group's Review of Particle Physics[#Yao:2006px##1###]. Using (for
the most part) their notation and descriptions, for a particle with
charge #tex2html_wrap_inline417# of momentum #tex2html_wrap_inline419# in a uniform magnetic field #tex2html_wrap_inline421# with a
pitch3 angle #tex2html_wrap_inline427#
where #tex2html_wrap_inline429# is the radius of curvature in the projection of the
trajectory onto the bend plane, #tex2html_wrap_inline431# is in GeV/c, #tex2html_wrap_inline433# is in Tesla, and
#tex2html_wrap_inline435# is in meters. In the remainder of this note it will be assumed
that #tex2html_wrap_inline437#. Further, the magnetic field is assumed to be uniform
everywhere and in the #tex2html_wrap_inline439#-direction. The curvature #math15##tex2html_wrap_inline441#.
The variance of #tex2html_wrap_inline443# has two contributions,
where #tex2html_wrap_inline445# is the position resolution in meters, #tex2html_wrap_inline447#
is the projected length of the track onto the bending plane in meters
and #tex2html_wrap_inline449# is the number of measurements.
where #tex2html_wrap_inline451# is the number of radiation lengths in the detector
and #tex2html_wrap_inline453# is the total track length in the detector. For the momentum
estimate, the amount of material in front of the detector is ignored.