Measurement of normalized differential $\mathrm{t}\overline{\mathrm{t}}$ cross sections in the dilepton channel from pp collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper reports precise measurements of normalized differential cross sections for top quark pair production in dilepton channels at 13 TeV, comparing results with advanced theoretical models and simulations.

Contribution

It provides the first detailed differential measurements of top quark pair production at 13 TeV in dilepton channels, with comparisons to NLO and NNLO theoretical predictions.

Findings

Results agree with NLO and NNLO calculations within uncertainties.

Differential cross sections as functions of leptons, jets, and top quarks are provided.

Data constrains theoretical models of top quark production.

Abstract

Normalized differential cross sections for top quark pair production are measured in the dilepton (e$^+$e$^-$, $\mu^+\mu^-$, and $\mu^\mp$e$^\pm$) decay channels in proton-proton collisions at a center-of-mass energy of 13 TeV. The measurements are performed with data corresponding to an integrated luminosity of 2.1 fb$^{-1}$ using the CMS detector at the LHC. The cross sections are measured differentially as a function of the kinematic properties of the leptons, jets from bottom quark hadronization, top quarks, and top quark pairs at the particle and parton levels. The results are compared to several Monte Carlo generators that implement calculations up to next-to-leading order in perturbative quantum chromodynamics interfaced with parton showering, and also to fixed-order theoretical calculations of top quark pair production up to next-to-next-to-leading order.