Search for charged lepton flavor violation in the top quark sector in trilepton final states with the CMS detector at $\sqrt{s} = 13~\mathrm{TeV}$

A search for charged lepton flavor violation has been performed in the top quark sector through both top quark production and decay signal processes. The data were collected by the CMS experiment from proton-proton collisions at a center-of-mass energy of $13~\mathrm{TeV}$ and correspond to an integrated luminosity of $138~\mathrm{fb}^{-1}$. The selected events are required to contain one opposite-charge electron-muon pair, a third charged lepton (electron or muon), at least one jet, and at most one jet associated with a bottom quark. The analysis utilizes boosted decision trees to separate background processes from a possible signal. The data are found to be consistent with the standard model expectation. Observed exclusion limits are placed at the $95\%$ confidence level on the branching ratios $\mathrm{t} \rightarrow \mathrm{e}\mu\mathrm{u}$ ($\mathrm{t} \rightarrow \mathrm{e}\mu\mathrm{c}$) of $0.023 \times 10^{-6}$ ($0.258\times 10^{-6}$), $0.016 \times 10^{-6}$ ($0.199 \times 10^{-6}$), and $0.009 \times 10^{-6}$ ($0.105 \times 10^{-6}$) for tensor, vector, and scalar interactions, respectively. $$\textit{This document has been revised with respect to the version dated February 27, 2023.}$$