Evidence for Top Quark Production in Nucleus-Nucleus Collisions

CMS Collaboration

doi:10.1103/PhysRevLett.125.222001

Evidence for Top Quark Production in Nucleus-Nucleus Collisions

CMS Collaboration

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

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 language	English
Article number	222001
Journal	Physical Review Letters
Volume	125
Issue number	22
DOIs	https://doi.org/10.1103/PhysRevLett.125.222001
State	Published - Nov 24 2020

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10.1103/PhysRevLett.125.222001

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@article{50d991c5641e426dbec8adcf3cd3415b,

title = "Evidence for Top Quark Production in Nucleus-Nucleus Collisions",

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.",

author = "{CMS Collaboration} and Sirunyan, {A. M.} and A. Tumasyan and W. Adam and F. Ambrogi and B. Arnold and H. Bergauer and T. Bergauer and M. Dragicevic and J. Er{\"o} and {Del Valle}, {A. Escalante} and M. Flechl and R. Fr{\"u}hwirth and M. Jeitler and N. Krammer and I. Kr{\"a}tschmer and D. Liko and T. Madlener and I. Mikulec and N. Rad and J. Schieck and R. Sch{\"o}fbeck and M. Spanring and S. Templ and W. Waltenberger and Wulz, {C. E.} and M. Zarucki and V. Drugakov and V. Mossolov and Gonzalez, {J. Suarez} and Darwish, {M. R.} and {De Wolf}, {E. A.} and {Di Croce}, D. and X. Janssen and T. Kello and A. Lelek and M. Pieters and Sfar, {H. Rejeb} and {Van Haevermaet}, H. and {Van Mechelen}, P. and {Van Putte}, S. and {Van Remortel}, N. and F. Blekman and Bols, {E. S.} and Chhibra, {S. S.} and J. D'hondt and {De Clercq}, J. and N. Akchurin and S. Kunori and I. Volobouev and A. Whitbeck",

note = "Publisher Copyright: {\textcopyright} 2020 CERN.",

year = "2020",

month = nov,

day = "24",

doi = "10.1103/PhysRevLett.125.222001",

language = "English",

volume = "125",

journal = "Physical Review Letters",

issn = "0031-9007",

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T1 - Evidence for Top Quark Production in Nucleus-Nucleus Collisions

AU - CMS Collaboration

AU - Sirunyan, A. M.

AU - Tumasyan, A.

AU - Adam, W.

AU - Ambrogi, F.

AU - Arnold, B.

AU - Bergauer, H.

AU - Bergauer, T.

AU - Dragicevic, M.

AU - Erö, J.

AU - Del Valle, A. Escalante

AU - Flechl, M.

AU - Frühwirth, R.

AU - Jeitler, M.

AU - Krammer, N.

AU - Krätschmer, I.

AU - Liko, D.

AU - Madlener, T.

AU - Mikulec, I.

AU - Rad, N.

AU - Schieck, J.

AU - Schöfbeck, R.

AU - Spanring, M.

AU - Templ, S.

AU - Waltenberger, W.

AU - Wulz, C. E.

AU - Zarucki, M.

AU - Drugakov, V.

AU - Mossolov, V.

AU - Gonzalez, J. Suarez

AU - Darwish, M. R.

AU - De Wolf, E. A.

AU - Di Croce, D.

AU - Janssen, X.

AU - Kello, T.

AU - Lelek, A.

AU - Pieters, M.

AU - Sfar, H. Rejeb

AU - Van Haevermaet, H.

AU - Van Mechelen, P.

AU - Van Putte, S.

AU - Van Remortel, N.

AU - Blekman, F.

AU - Bols, E. S.

AU - Chhibra, S. S.

AU - D'hondt, J.

AU - De Clercq, J.

AU - Akchurin, N.

AU - Kunori, S.

AU - Volobouev, I.

AU - Whitbeck, A.

PY - 2020/11/24

Y1 - 2020/11/24

N2 - 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.

AB - 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.

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U2 - 10.1103/PhysRevLett.125.222001

DO - 10.1103/PhysRevLett.125.222001

M3 - Article

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AN - SCOPUS:85097318502

SN - 0031-9007

VL - 125

JO - Physical Review Letters

JF - Physical Review Letters

IS - 22

M1 - 222001

ER -

Evidence for Top Quark Production in Nucleus-Nucleus Collisions

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