Flavour Identification Techniques

Over time several algorithms have been developed for flavour identification/tagging for various colliders. There is an advantage in studying a newly discovered particle in electron-positron colliders since they allow to study this particle in a clean environment, owing to the fact that the incoming particles do not leave any residuals, unlike the QCD background in hadron collisions. In hadron colliders, in addition, the initial state is not known precisely, which further limits the high-precision measurements. This thesis reports on the study and implementation of flavour identification algorithms to distinguish the hadronic decay channels of the $Z$ boson. The study has been performed in an environment compatible with proposed future $e^{+}e^{-}$ circular colliders like the Future Circular Collider (FCC). The first algorithm presented here is the Impact Parameter Algorithm, which produced a 23.16% rate of misidentification of $Z \rightarrow c\bar{c}$ events and a 1.74% rate of misidentification of $Z \rightarrow q' \bar{q'}$ events, with $q' \equiv (u, d, s)$, for an 80% efficiency of accurate identification of the $Z \rightarrow b \bar{b}$ events. The other algorithm, inspired by the techniques presented in the LCFIPlus framework, developed for future $e^{+}e^{-}$ linear colliders like the International Linear Collider (ILC), classifies events into four categories through secondary vertex reconstruction, with each category representing the majority of decay events to a certain hadronic flavour.