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routine to estimate charged particle resolution

Just put up a wiki page describing it at 
http://www.jlab.org/Hall-D/software/wiki/index.php/Tracking_resolution_estimator_%28REZEST%29 
. A text version is also attached.


Tracking resolution estimator (REZEST)

   The "rezest" package contains FORTRAN routines that calculate estimates
   of the momentum and angular resolutions for charged particles in GlueX.
   Simplifying assumptions are made and the resolutions functions are
   calculated analytically a là the Particle Data Group.

   The principal subroutine is documented in the source code file
   rezest_fdc_cdc.F:

      SUBROUTINE REZEST_FDC_CDC(P, LAMBDA, M,
     X     DP_OVER_P, DPHI_TOT, DTHETA_TOT)
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
C
C
C This routine estimates the resolution in GlueX for charged particles
C in tranverse momentum, azimuthal angle, and polar angle.
C
C Input arguments, all REAL*4
C
C     P        Magnitude of total momentum (GeV/c)
C     LAMBDA   Dip angle, difference in polar angle in lab between track
C              and pi/2 (i. e., 90 degrees) (radians)
C     M        Mass of the particle (GeV/c^2)
C
C Output arguments, all REAL*4
C
C     DP_OVER_P  Relative resolution in transverse momentum ("sigma_{p_t}/p_t")
C     DPHI_TOT   Resolution in azimuthal angle ("sigma_phi")
C     DTHETA_TOT Resolution in polar angle ("sigma_theta")
C
C The routine combines the measurements in the FDC and CDC where
C appropriate. Parameters describing the geometry and materials are
C defined in the routine REZEST_COMPONENTS which appears below.
C

Getting the code

   Two methods:
    1. Get the tar ball. Ref [10].
    2. Check it out from the subversion repository:

 svn checkout https://halldsvn.jlab.org/repos/trunk/home/marki/gluex/rezest
                                                                 Ref. [11]


Building the files

   There is a simple makefile in the directory:

> cd rezest
> make
gfortran -g   -c -o rezest.o rezest.F
gfortran -g   -c -o rezest_fdc_cdc.o rezest_fdc_cdc.F
ar rcv librezest.a rezest.o rezest_fdc_cdc.o
a - rezest.o
a - rezest_fdc_cdc.o
gfortran -g   -c -o rezest_point.o rezest_point.F
gfortran -o rezest_point rezest_point.o -L. -lrezest
gfortran -g   -c -o rezest_point_comp.o rezest_point_comp.F
gfortran -o rezest_point_comp rezest_point_comp.o -L. -lrezest

   This creates three files that you care about:
    1. librezest.a: the object library
    2. rezest_point: a binary
    3. rezest_point_comp: a binary


Using the files


librezest.a

   Link this into your own program to retrieve resolution values.

rezest_point

   This stand-alone binary will accept three arguments on standard input
   (space separated on a single line) and will write the resolution values
   on standard output.

   Input:
    1. total magnitude of momentum in GeV/c
    2. dip angle in radians (see definition above in the source code
       snippet)
    3. mass in GeV/c^2

   Output:
    1. relative resolution in transverse momentum
    2. resolution in azimuthal angle
    3. resolution in polar angle

   For example:

> rezest_point
1.0 1.22 0.139
  2.8597742E-02  1.6185496E-02  8.1181811E-04

   says that a 1 GeV/c particle traveling in a direction 1.22 radians
   forward of the transverse direction with a mass of 139 MeV has an
   estimated sigma_{p_t}/p_t = 2.9\% , sigma\phi = 16 mR, and
   sigma_theta = 0.8 mR.

rezest_point_comp

   Same as rezest_point except that the individual components of the
   resolution are listed. Note that the first three numbers being output
   are the same as for rezest_point.

   Output:
    1. relative resolution in transverse momentum
    2. resolution in azimuthal angle
    3. resolution in polar angle
    4. resolution in curvature (1 / R[curvature]) due to multiple
       scattering in the FDC in inverse meters
    5. same for CDC
    6. resolution in curvature due to position resolution in the FDC
    7. same for CDC
    8. total resolution in curvature in the FDC
    9. same for the CDC
   10. resolution in azimuthal angle (phi) due to multiple scattering in the
       FDC in radians
   11. same for CDC
   12. resolution in azimuthal angle due to position resolution in the FDC
   13. same for CDC
   14. resolution in azimuthal angle due to curvature resolution in the
       FDC
   15. same for CDC
   16. total resolution in azimuthal angle in the FDC
   17. same for the CDC
   18. resolution in polar angle (theta) due to multiple scattering in the FDC
       in radians
   19. same for CDC
   20. resolution in polar angle due to position resolution in the FDC in
       radians
   21. same for CDC
   22. total resolution in polar angle in the FDC
   23. same for the CDC

   For example:

> rezest_point_comp
1.0 1.22 0.139
  2.8597742E-02  1.6185496E-02  8.1181811E-04  4.2887099E-02
  2.2642065E-02  1.3919008E-02  0.1605156      4.5089267E-02
  0.1621047      2.5197803E-03  3.1950074E-04  5.0111138E-04
  2.4516270E-03  1.7020071E-02  4.7496673E-02  1.7212879E-02
  4.7560975E-02  2.5197803E-03  3.1950074E-04  7.7741774E-04
  7.9118297E-04  2.6369814E-03  8.5325917E-04

   (All values in the output actually appear on one line.)

   Retrieved from
   "http://www.jlab.org/Hall-D/software/wiki/index.php/Tracking_resolution_estimator_%28REZEST%29"

References

  10. http://www.jlab.org/~marki/misc/rezest_2008-02-28.tar
  11. https://halldsvn.jlab.org/repos/trunk/home/marki/gluex/rezest

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fn:Mark M. Ito
n:Ito;Mark
org:Jefferson Lab
adr:Suite 8;;12000 Jefferson Avenue;Newport News;VA;23601;USA
email;internet:marki@jlab.org
title:Staff Scientist
tel;work:757-269-5295
tel;fax:757-269-6331
tel;pager:757-584-5295
url:http://www.jlab.org/~marki
version:2.1
end:vcard