| dc.description.abstract | In this thesis, the results for a simulation of the ALICE EMCal trigger bias on the production of D*+ mesons are presented. The implementation of EMCal triggers in pp √ s = 13 TeV collisions was simulated by using PYTHIA 8.2 Monte Carlo simulations, producing a sample of 200 million events. Several triggers were considered, triggering exclusively on either electrons, photons or both, in combination with two trigger energy thresholds of 2 and 5 GeV. The EMCal trigger was simulated with an acceptance range of |η| < 0.7 and $0° < φ < 110°. The trigger bias was measured by calculating the enhancement factor for the yield of D*+ as a function of pt, φ and η; and by calculating the enhancement factor for the beauty fraction.
The 5 GeV electron trigger performs best when compared to other triggers: the trigger sample yields a general enhancement factor of 41 ± 1.3. The 2 GeV electron trigger sample yields an enhancement factor of 30.5 ± 0.3. The enhancement factor inside the EMCal φ and η acceptance range is significantly higher than outside this range. This leads to the conclusion that the trigger particles most frequently have their origin in the same fragmentation and decay chain as the observed D*+ meson.
In the high pt limit, the 5 GeV electron trigger sample yields a maximum enhancement factor of 1.5146*10^6 ± 1*10^3. An enhancement in the beauty feed-down fraction of all D*+ is observed, from a fraction of 0.1077 ± 0.0003 for the minimum bias sample to 0.58 ± 0.03 for the 5 GeV electron trigger sample. The highest beauty enhancement is observed in the low pt range, in the high pt limit the beauty fraction in all trigger samples match the minimum bias beauty fraction.
A recommendation is made for the implementation of the 5 GeV electron EMCal trigger in the ALICE detector, because of its performance in the general enhancement of the D*+ yield; in the enhancement in the high pt limit; and in the enhancement of the beauty fraction. The consequences of the trigger implementation, regarding the reduction in the amount of events, need to be determined in future studies. | |
