Track error and vertex reconstruction
22.03.2017
Benedikt Würkner
Overview
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Change of track error with move from z=0 to
z=2100 for track fit
Influence of Vertexing algorithm using track
error
22.03.2017
Benedikt Würkner
Changing track fitting (1)
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From z=0 to z=2100 (close to the actual detector)
Mentioned this before, now demonstrating why this is a good idea
22.03.2017
Benedikt Würkner
Changing track fitting (2)
22.03.2017
Benedikt Würkner
Changing track fitting (3)
22.03.2017
Benedikt Würkner
Comparison of filters
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”standard”
Filtering tracks
using abs(sigmaX-sigmaY) < 0.2
different settings
22.03.2017
Benedikt Würkner
New Vertexing using track error
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Simple Vertexing algorithm only uses the distance
between two tracks in 3D space as a starting point and
continues from there
No limits in x, y or z imposed on the vertex, can also be
outside of the volume, between the planes, …
“Simple” version only using one upper limit for track
distance
“New” version uses only error at z-position of the tracks for
limit, should therefore give preferred treatment to low z
values since the error range there is bigger
22.03.2017
Benedikt Würkner
22.03.2017
Benedikt Würkner
22.03.2017
Benedikt Würkner
Summary
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Moving of fitting point removes the artifact of the ”rainbow” and
therefore definitely makes sense
Also makes the track fit error linear which makes sense
Comparison of filters shows, that sadly we still don’t have a way
to filter the events without using the vertex information
Also shows that the acceptance in z<1000 is now way better
since the bigger error range allows for additional vertices to be
found
More vertices are found by the algorithm using the error but
also more vertices outside of the 20x20mm area in the plot (but
percentage wise stays consistent)
22.03.2017
Benedikt Würkner