Physics Department,
University of California,
One Shields Avenue,
Davis, CA 95616
This is the momentum resolution of the TPC at mid rapidity as a function of mt for various particles. The
resolution is defined by abs(Pr-Pg)/Pg, where Pr is the reconstructed momentum and Pg is the geant momentum.
The plots below are profile plots so the line represent the average resolution in a given bin and the errors
are error in the mean. The tracks in the flowing plots are embedded
tracks in real events using the slow simulator.
pion minus
pion plus
proton
Helium 3
The following is the same as above except the resolution is defined in mt
instead of momentum.
pion minus
pion plus
proton
Helium 3
The following plots show the same resolution from the trackdbg table in
nhits bins. The cuts used are
Where the nrec cut is adjusted for each slice shown below. No refitting.
proton nhits 15-30
proton nhits 30-40
proton nhits 40-55
proton nhits 55-75
proton nhits 75-128
Notice that these plots are generated out to a total p of 5 GeV and do not go to
zero. This is because these are tracks at the center of mass. The fast simulator
from Mike Lisa goes to zero, and does not extend as high in p. When I compare the
results here properly(namly high nhits at cm) to Mike's
results
I find that things are similar except for
low nhits particles. I think this is because a low nhits particle at mid-rapidty is
not as good of a backward particle with low nhits. He simulated full RQMD events
and looked at the average momentum resolution. The resolution plots here only are
for the mid-rapidity space.
This is the same as the above plots except that the theoretical curves are also put on the plot. The
two lines represent the expected momentum resolution. Each line represents the expected resolution
for the extreme valuses of the nhits bins. For example in the first plot, one line is for 15 hits,
and the other line is for 30 hits. The spacial hit resolution is assumed to be 750microns.
proton nhits 15-30
proton nhits 30-40
proton nhits 40-55
proton nhits 55-75
proton nhits 75-128
This is the same as above with the change in the distortion correction.
It was found that the distortion correction was being applied twice. The
plots below are proply done.(distortion correction applies once)
Nuclear Physics Group
