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We have generated W bosons isotropically in the momentum range
with .The generated events are passed through the JLC-standard-detector
simulation and the invariant mass of the final state particles
is calculated for each event without any selection cuts.
Fig.3.1 compares the invariant mass distribution
for calorimetric information only and
that after the new cluster-track matching.
Figure 3.1:
Reconstructed W mass distributions for
(left) calorimetric information only and
(right) combined track information.
In the cluster-track matching
2- cut is used to delete global clusters.
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Fig.3.2 corresponds to blown-up
of Fig.3.1, again (left) for calorimetric information only
and (right) for combined track information.
The figure tells us that, after the new cluster-track
matching we have
not too good showing the 2- cut is to much, while
the mass resolution improves to
which is quite good compared to the mass resolution
in excess of with the calorimetric information only.
Figure 3.2:
Blown-up figure of Fig.3.1, where the
smooth curves are the result of Gaussian-fits:
(left) calorimetric information only and
(right) combined track information.
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When we examine the mass distribution as a function of momentum,
we get Fig.3.3.
Figure 3.3:
Reconstructed W mass plotted against W momentum
and its standard deviation and center value as functions of
the W momentum:
(left) calorimetric information only and
(right) combined track information.
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We can see that both the resolution and the center value are
momentum-dependent even after the new cluster-track matching:
at best, while
the center value decreases with momentum, showing that
the rate of cluster misdeletions goes up with momentum.
The mass resolution and the systematic shift of the center value
depend on the choice of the cut.
Next: Higgs Mass Reconstruction
Up: Performance
Previous: Performance
Keisuke Fujii
12/3/1998