Evidence for Top Quark Production in Nucleus-Nucleus Collisions

(CMS Collaboration)

Research output: Contribution to journalArticlepeer-review

Abstract

Ultrarelativistic heavy ion collisions recreate in the laboratory the thermodynamical conditions prevailing in the early universe up to 10-6 sec, thereby allowing the study of the quark-gluon plasma (QGP), a state of quantum chromodynamics (QCD) matter with deconfined partons. The top quark, the heaviest elementary particle known, is accessible in nucleus-nucleus collisions at the CERN LHC, and constitutes a novel probe of the QGP. Here, we report the first evidence for the production of top quarks in nucleus-nucleus collisions, using lead-lead collision data at a nucleon-nucleon center-of-mass energy of 5.02 TeV recorded by the CMS experiment. Two methods are used to measure the cross section for top quark pair production (σtt) via the selection of charged leptons (electrons or muons) and bottom quarks. One method relies on the leptonic information alone, and the second one exploits, in addition, the presence of bottom quarks. The measured cross sections, σtt=2.54-0.74+0.84 and 2.03-0.64+0.71 μb, respectively, are compatible with expectations from scaled proton-proton data and QCD predictions.

Original languageEnglish
Article number222001
JournalPhysical Review Letters
Volume125
Issue number22
DOIs
Publication statusPublished - 24 Nov 2020

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Evidence for Top Quark Production in Nucleus-Nucleus Collisions'. Together they form a unique fingerprint.

Cite this