Observation of; ; ; t; W; Z; ; ; Production at the CMS Experiment Journal Article

Overview

; The first observation of single top quark production in association with a; ; W; ; and a; ; Z; ; boson in proton-proton collisions is reported. The analysis uses data at center-of-mass energies of 13 and 13.6 TeV recorded with the CMS detector at the CERN LHC, corresponding to a total integrated luminosity of; ; 200; ; ; ; fb; ; −; 1; ; ; ; . Events with three or four charged leptons, which can be electrons or muons, are selected. Advanced machine-learning algorithms and improved reconstruction methods, compared to an earlier analysis, result in an unprecedented sensitivity to; ; t; W; Z; ; production. The measured cross sections for; ; t; W; Z; ; production are; ; 248; ±; 52; ; ; fb; ; and; ; 242; ±; 77; ; ; fb; ; for; ; ; s; ; =; 13; ; and 13.6 TeV, respectively. The signal is established with a statistical significance of 5.8 standard deviations, with 3.5 expected, compared to the background-only hypothesis.;

Hayrapetyan A; Makarenko V; Tumasyan A; Adam W; Andrejkovic JW; Benato L; Bergauer T; Dragicevic M; Giordano C; Hussain PS