Evidence for Top Quark Production in Nucleus-Nucleus Collisions

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F20%3A10424090" target="_blank" >RIV/00216208:11320/20:10424090 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=w4jk_4gZtX" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=w4jk_4gZtX</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevLett.125.222001" target="_blank" >10.1103/PhysRevLett.125.222001</a>

Result language
angličtina
Original language name
Evidence for Top Quark Production in Nucleus-Nucleus Collisions
Original language description
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 (sigma(t (t) over bar)) 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, sigma(t (t) over bar) = 2.54(-0.74)(+0.84) and 2.03(-0.64)(+0.71) mu b, respectively, are compatible with expectations from scaled proton-proton data and QCD predictions.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10303 - Particles and field physics

Project
<a href="/en/project/LM2018104" target="_blank" >LM2018104: Research Infrastructure for experiments at CERN</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2020
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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