Top-mass observables: all-orders behaviour, renormalons and NLO + Parton Shower effects

Understand

In this thesis we focus on the theoretical subtleties of the top-quark mass ($m_t$) determination, issue which persists in being highly controversial.

• In the first part of the thesis, we investigate the presence of linear renormalons in observables that can be employed to determine the top mass.
• We considered a simplified toy model to describe $W^{*} \rightarrow t \bar{b} \to Wb \bar{b}$.
• The computation is carried out in the limit of a large number of flavours ($n_f$), using a new method that allows to easily evaluate any infrared safe observable at order $\alpha_s(\alpha_s n_f)^n$ for any $n$.