10 - H1 - Desy
10 - H1 - Desy
10 - H1 - Desy
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8.7 Corrections to the QCD calculations 125<br />
isol<br />
theor<br />
1.1<br />
isol<br />
theor<br />
1.1<br />
isol<br />
theor<br />
1.1<br />
1.05<br />
1.05<br />
1.05<br />
1<br />
1<br />
1<br />
0.95<br />
0.9<br />
6 8 <strong>10</strong> 12 14 γ<br />
E T [GeV]<br />
i<br />
0.95<br />
0.9<br />
-1 0 1 2<br />
ii<br />
γ<br />
η<br />
0.95<br />
iii<br />
0.9<br />
6 8 <strong>10</strong> 12 14 γ<br />
E T [GeV]<br />
isol<br />
theor<br />
1.1<br />
isol<br />
theor<br />
1.1<br />
isol<br />
theor<br />
1.1<br />
1.05<br />
1.05<br />
1.05<br />
1<br />
1<br />
1<br />
0.95<br />
iv<br />
0.9<br />
-1 0 1 2<br />
γ<br />
η<br />
0.95<br />
0.9<br />
v<br />
5 <strong>10</strong> 15<br />
jet<br />
E T [GeV]<br />
0.95<br />
0.9<br />
vi<br />
-1 0 1 2<br />
jet<br />
η<br />
isol<br />
theor<br />
1.1<br />
isol<br />
theor<br />
1.1<br />
isol<br />
theor<br />
1.1<br />
1.05<br />
1.05<br />
1.05<br />
1<br />
1<br />
1<br />
0.95<br />
vii<br />
0.9<br />
0 0.5 1<br />
LO x γ<br />
0.95<br />
0.9<br />
viii<br />
0.02 0.04 0.06<br />
LO x p<br />
0.95<br />
ix<br />
0.9<br />
0 2 4 6 8<br />
p<br />
isol<br />
theor<br />
1.1<br />
isol<br />
theor<br />
1.1<br />
isol<br />
theor<br />
1.1<br />
1.05<br />
1.05<br />
1.05<br />
1<br />
1<br />
1<br />
0.95<br />
x<br />
0.9<br />
130 140 150 160 170 180<br />
∆φ<br />
0.95<br />
xi<br />
0.9<br />
0 2 4 6 8<br />
p<br />
0.95<br />
xii<br />
0.9<br />
130 140 150 160 170 180<br />
∆φ<br />
Figure 8.15: Isolation correction ftheor isol as determined for all the final cross sections. The<br />
cross sections codes as defined in table 8.1 are given in relevant places.<br />
ftheor had is determined for each bin i: ftheor,i had = Nhad i /N par<br />
i , (8.53)<br />
where Ni<br />
had and N par<br />
i is the number of generated events in the given phase space in<br />
bin i on hadron and parton level respectively. Since the hadronisation in MC can be<br />
calculated using two competitive methods (see section 2.1.1), the correction factor ftheor<br />
had<br />
is determined with the help of two different Monte Carlo generators. The actual correction<br />
factor is taken as the mean value between the correction factor obtained with PYTHIA<br />
MC (using Lund fragmentation model) and with HERWIG MC (CDF model), while half<br />
of the difference between them determines the corresponding uncertainty.<br />
The correction factors for all the final cross sections is shown in figure 8.16. For the<br />
inclusive cross sections, the hadronisation correction is most significant for low transverse<br />
energies and in the forward direction. At low energies hadron level jets are statistically<br />
wider which may affect the resolution in the isolation of the photon. In the forward region<br />
of the detector, the proton remnant creates higher local particle density and thus more<br />
sensitivity to the isolation cut. For the exclusive cross section, correction factors obtained
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