Browsing by Subject ""next to leading order""

This works aim is primarily the implementation of b-quarks into the event generator PHOJET (respectively into DPMJET III containing PHOJET). Following a method of S. Frixione and B.R. Webber the implementation includes "next to leading order" in a perturbative expansion on partonic level. A typical problem of such a calculation in event generators that include initial and final state radiation is "double counting". To overcome this error Frixione and Webber developed a scheme involving subtraction terms. In this thesis this elaborate method is adapted and implemented in DPMJET III by means of recalculation of this subtraction term to match DPMJET III needs (chapter 4 and sections 5.4, 5.5 as well as the section 6.3. The correct outcome of this matching is shown in chapter 7 by means of production of vector bosons. In contrast to the event generator HERWIG it is found, that DPMJET III is able to reproduce the correct partonic behavior in the "soft"' and "collinear"' limits, when one additional parton is emitted. After a short description of the method of event generation this work presents, beginning with chapter 9 the results of the calculation which are then compared to available experimental data provided by the CDF collaboration (RUN I and II). A moderate adjustment of the two relevant scales (factorization and renormalization scales) leads to good agreement between model prediction and the CDF data. Subsequently the predictions for the transverse spectra of bottom mesons at LHCb (section 10.1) are presented. As the adjusted factorization and renormalization scales were kept, the results can be expected to be quite reliable. DPMJET III and PHOJET are highly checked out and complete event generators that can reliably reproduce the background part of the events. It is therefore possible to address more technical questions like the identification of B-mesons in realistic events to DPMJET III. To investigate this task in a generic way a small program was built to identify daughter particles of specific bottom decays with suitable cuts on an event.