Observation of top quark production in proton-nucleus collisions

TL;DR

This paper reports the first observation of top quark production in proton-nucleus collisions at the LHC, confirming quantum chromodynamics predictions with a significance above five standard deviations.

Contribution

It provides the first measurement of top quark production in proton-nucleus collisions, expanding understanding of top quark behavior in nuclear environments.

Findings

Significant observation of top quark production with over five sigma confidence.

Measured cross section aligns with quantum chromodynamics predictions.

First detection of top quarks in proton-nucleus collision data.

Abstract

The first observation of top quark production in proton-nucleus collisions is reported using proton-lead data collected by the CMS experiment at the CERN LHC at a nucleon-nucleon center-of-mass energy of sqrt(s[NN]) = 8.16 TeV. The measurement is performed using events with exactly one isolated electron or muon and at least four jets. The data sample corresponds to an integrated luminosity of 174 inverse nanobarns. The significance of the tt-bar signal against the background-only hypothesis is above five standard deviations. The measured cross section is sigma[tt-bar] = 45 +/- 8 nb, consistent with predictions from perturbative quantum chromodynamics.