TWOGAM is the MC generator that is most commonly used in DELPHI and was therefore used in this analysis. The TWOGAM generator has the advantage of generate the different model constituencies separately, which allows to easily qualify the importance of a model in a certain Q2 region. For this analysis five data sets were generated by the TWOGAM generator, presented in Table 7.1.
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The generated MC events are then processed through two simulators, DELSIM [35] and FASTSIM [36], in order to generate the detector response for the DELPHI and VSAT detectors respectively. It is vital that the coordinate systems of DELPHI and VSAT are the same as the one of the generated MC. The DELPHI coordinate system is fixed with help of the vertex detector, that can measure the location of the interaction point very accurate. The VSAT position is fixed by using the symmetries of Bhabha events [37].
As mentioned in section 6.2 the QPM model describes data at high Q2, and is of less importance in the VSAT region (which has a Q2 between 0.02 and 0.6). The size of the QCD-RPC model depends on the value chosen for the pTmin cut-off limit for the Parton Density Functions. As seen from Fig 7.1 even a small change in the pTmin value will make a clear change in the size of the QCD-RPC contribution. The weights of each of the contributions for a pTmin of 2.05 are shown in Fig. 7.2.
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