10 - H1 - Desy

88 Calibration and tuning
χ
2 /NDF
12
10
8
6
4
R T
-2 0 2 4
χ
2 /NDF
10
K T
8
6
4
2
k
-10 -5 0 5
χ
2 /NDF
25
20
FLF
15
10
5
k
-10 -5 0 5
k
χ 2 /NDF
10
HCF
χ
2 /NDF
10 HCellF
χ
2 /NDF
10
S T
5
5
5
-2 0 2
k
-5 0 5
k
-5 0 5
k
Figure 7.3: The χ 2 /NDF dependence on the stretching factor k for six cluster shape
variables in the CB1 wheel for the background enhanced sample.
CB1 CB2 CB3 FB1 FB2 IF1
R T −0.5 ± 1.5 0.0 ± 1.0 −1.0 ± 1.5 −1.5 ± 1.5 0.0 ± 4.0 +2.0 ± 8.0
K T 0.0 ± +4.0 −1.0 ± 3.0 −0.5 ± 2.5 +1.0 ± 2.0 0.0 ± 5.0 +6.0 ± 10.0
S T +0.2 ± 1.8 0.0 ± 1.5 +1.0 ± 2.0 +1.5 ± 2.5 +2.0 ± 4.0 0.0 ± 5.0
HCellF +1.0 ± 1.5 0.0 ± 1.5 0.0 ± 1.5 −0.8 ± 2.2 −5.0 ± 5.0 +5.0 ± 7.5
HCF +0.5 ± 1.0 +0.5 ± 0.5 +0.2 ± 0.5 +0.5 ± 1.0 +2.0 ± 4.0 −1.5 ± 3.5
FLF +1.0 ± 2.0 +0.5 ± 2.0 +1.5 ± 2.5 +5.0 ± 5.0 +10.0 ± 10.0 +4.0 ± 10.0
Table 7.1: Stretching factors k and they uncertainties as determined for six cluster
shapes.
7.2 Photon energy calibration
The energy calibration of the LAr calorimeter was originally calibrated using test beam
measurements [102, 103]. Since then, more precise calibration using real data was performed
[118] with electrons in high Q 2 neutral current events. This provides a good
calibration at higher energies.
Since analysis uses low energetic clusters, the energy calibration factors were cross checked