Full Event Interpretation

Abstract

The Full Event Interpretation (FEI) is a tagging algorithm based on machine learning. It exploits the unique experimental setup of \(\text {B}\) factory experiments such as the Belle and Belle II experiment. Both experiments operate on the \(\Upsilon (4\text {S})\) resonance, which decays at least \(96 \%\) of the time into exactly two \(\text {B}\) mesons. Conceptually, the event is divided into two sides: The signal-side containing the tracks and clusters compatible with the assumed signal \(\text {B}_{\mathrm {sig}} \) decay the physicist is interested in, e.g. \(\text {B}^{+}\rightarrow \tau ^{+}\nu _{\tau }\); and the tag-side containing the remaining tracks and clusters compatible with an arbitrary \(\text {B}_{\mathrm {tag}} \) meson decay. Figure 4.1 depicts this situation.