Dortmund 2021 – scientific programme

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T: Fachverband Teilchenphysik

T 28: Top quark production II

T 28.6: Talk

Tuesday, March 16, 2021, 17:15–17:30, Tc

Measurement of the dileptonic tt differential cross section in a BSM phase space at CMS — Lutz Feld, •Danilo Meuser, Johannes Schulz, and Marius Teroerde — I. Physikalisches Insitut B, RWTH Aachen University

Measurements of the tt production cross section yield important precision tests of the Standard Model (SM), while also probing scenarios for physics beyond the SM (BSM). Although the dileptonic channel has the lowest branching ratio of all tt decay channels, its sensitivity is large due to small contributions from other SM processes.

This analysis aims to measure the tt cross section in a phase space where additional contributions from BSM scenarios could be present. It is based on the data set recorded by CMS in the years 2016 to 2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137.2 fb⁻¹. The BSM scenarios considered include supersymmetric and dark matter models, where, similarly to the dileptonic tt channel, two leptons, b jets and undetected particles are produced. Unlike previous measurements, where the differential cross sections were mainly measured as a function of kinematic variables of the leptons or top quarks, this analysis focuses on observables related to the neutrinos, like the missing transverse momentum and the angular distance between the missing transverse momentum and the nearest lepton, to separate BSM from SM tt events.