Optimization of Rare Event Selection in the Presence of Unextractable Dominant Background
摘要
We report an investigation of the influence of potential contamination of a background sample used for training and optimizing a selection by a small fraction of signal events on the multivariate classifier performance. The performance of the boosted decision tree (BDT) classifier trained and optimized on contaminated background sample containing mislabeled signal events is compared to the idealized case of pure training samples. It is demonstrated that the training of the selection is not significantly affected by the absolute number of mislabeled signal events for a given relative background sample contamination value (1000 : 1 background-to-signal ratio). In contrast, the resulting optimization of the selection requirement decreases as the mislabeled signal contribution increases.