Evidence for Top Quark Production in Nucleus-Nucleus Collisions
Name
PhysRevLett.125.222001.pdf
Description
Published version
Size
424.88 KB
Format
Adobe PDF
Checksum (MD5)
b15b858a8de270dd40b185dde9ede84f
Author(s)
Harris, Philip
Date Issued
2020
Journal
Physical Review Letters
Publisher
American Physical Society (APS)
Citation
Harris, Philip. 2020. "Evidence for Top Quark Production in Nucleus-Nucleus Collisions." Physical Review Letters, 125 (22).
Version
Final published version
Abstract
© 2020 CERN. 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.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/PHYSREVLETT.125.222001
