Improved Event-mixing for Resonance Measurements

Sammanfattning: This report first analyzed the reason for the deviation of the event-mixing method in background estimation for resonance research, and one possible explanation is that the event-mixing method can not reproduce the specific angular distribution of produced particles caused by jet-effects. This assumption was checked by Monte-Carlo simulations with PYTHIA, and a certain method of correction called reweighing was proposed to improve the event-mixing method. The improved event-mixing method was then applied for simulation as well as resonance analysis for experimental data from the ALICE experiment, and the results proved that this reweighing method can improve the performance on resonance signal extraction by reducing the residual background.