Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sNN =5.02 TeV

(ALICE Collaboration)

doi:10.1103/PhysRevLett.126.162001

Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sNN =5.02 TeV

(ALICE Collaboration)

Relativistic Nuclear Physics

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

16 Scopus citations

Abstract

The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sNN=5.02 TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v2. The v2 coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (pT) range 1.3-6 GeV/c in the centrality class 30%-50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length cτ≈500 μm compared to that of charm hadrons and most of the other background sources. The v2 of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75 σ. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high pT, but is in agreement with the results at low pT. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.

Original language	English
Article number	162001
Journal	Physical Review Letters
Volume	126
Issue number	16
DOIs	https://doi.org/10.1103/PhysRevLett.126.162001
State	Published - Apr 19 2021

Funding

The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) Collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A.\u2009I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences, Austrian Science Fund (FWF): [M 2467-N36] and Nationalstiftung f\u00FCr Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Cient\u00EDfico e Tecnol\u00F3gico (CNPq), Financiadora de Estudos e Projetos (Finep), Funda\u00E7\u00E3o de Amparo \u00E0 Pesquisa do Estado de S\u00E3o Paulo (FAPESP) and Universidade Federal do Rio Grande do Sul (UFRGS), Brazil; Ministry of Education of China (MOEC), Ministry of Science & Technology of China (MSTC) and National Natural Science Foundation of China (NSFC), China; Ministry of Science and Education and Croatian Science Foundation, Croatia; Centro de Aplicaciones Tecnol\u00F3gicas y Desarrollo Nuclear (CEADEN), Cubaenerg\u00EDa, Cuba; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research | Natural Sciences, the VILLUM FONDEN and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat \u00E0 l\u2019Energie Atomique (CEA) and Institut National de Physique Nucl\u00E9aire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium f\u00FCr Bildung und Forschung (BMBF) and GSI Helmholtzzentrum f\u00FCr Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece; National Research, Development and Innovation Office, Hungary; Department of Atomic Energy Government of India (DAE), Department of Science and Technology, Government of India (DST), University Grants Commission, Government of India (UGC) and Council of Scientific and Industrial Research (CSIR), India; Indonesian Institute of Science, Indonesia; Centro Fermi-Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi and Istituto Nazionale di Fisica Nucleare (INFN), Italy; Institute for Innovative Science and Technology, Nagasaki Institute of Applied Science (IIST), Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS) KAKENHI, Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnolog\u00EDa, through Fondo de Cooperaci\u00F3n Internacional en Ciencia y Tecnolog\u00EDa (FONCICYT) and Direcci\u00F3n General de Asuntos del Personal Academico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; The Research Council of Norway, Norway; Commission on Science and Technology for Sustainable Development in the South (COMSATS), Pakistan; Pontificia Universidad Cat\u00F3lica del Per\u00FA, Peru; Ministry of Science and Higher Education, National Science Centre and WUT ID-UB, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics and Ministry of Research and Innovation and Institute of Atomic Physics, Romania; Joint Institute for Nuclear Research (JINR), Ministry of Education and Science of the Russian Federation, National Research Centre Kurchatov Institute, Russian Science Foundation and Russian Foundation for Basic Research, Russia; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; Suranaree University of Technology (SUT), National Science and Technology Development Agency (NSDTA) and Office of the Higher Education Commission under NRU project of Thailand, Thailand; Turkish Atomic Energy Agency (TAEK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America.

Funders	Funder number
Council of Scientific and Industrial Research, India
State Committee of Science and World Federation
Ministry of Communications and High Technologies
Department of Atomic Energy, Government of India
National Academy of Sciences of Ukraine
National Science and Technology Development Agency
National Research Foundation of Korea
Villum Fonden
Ministry of Education of the People's Republic of China
Narodowe Centrum Nauki
University Grants Commission
Institut National de Physique Nucléaire et de Physique des Particules
Science and Technology Facilities Council
Institute of Atomic Physics, Romania
General Secretariat for Research and Technology, Ministry of Education, Research and Religions
Institute for Innovative Science and Technology, Nagasaki Institute of Applied Science
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Institute of Atomic Physics and Ministry of Research and Innovation
Turkish Atomic Energy Agency
Korea Institute of Science and Technology Information
Knut och Alice Wallenbergs Stiftelse
Ministry of Science and Education and Croatian Science Foundation
Instituto Nazionale di Fisica Nucleare
Financiadora de Estudos e Projetos
Department of Science and Technology, Ministry of Science and Technology, India
Consejo Nacional de Ciencia y Tecnología
Helsinki Institute of Physics
Türkiye Atom Enerjisi Kurumu
Norges Forskningsråd
Yerevan Physics Institute
Natur og Univers, Det Frie Forskningsråd
Centre National de la Recherche Scientifique
Office of the Higher Education Commission
Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México
Bundesministerium für Bildung und Forschung
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
Danmarks Grundforskningsfond
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Suranaree University of Technology
Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear
Nemzeti Kutatási Fejlesztési és Innovációs Hivatal
Russian Foundation for Basic Research
NRU
GSI Helmholtzzentrum für Schwerionenforschung
U.S. Department of Energy
Ministry of Education and Science of the Russian Federation
Indian Institute of Space Science and Technology
Fundação de Amparo à Pesquisa do Estado de São Paulo
National Nuclear Research Center
WUT ID-UB
National Research Center "Kurchatov Institute"
Ministry of Science and Technology of the People's Republic of China
Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic
Ministry of Education, Science, Research and Sport
Russian Science Foundation
Lembaga Ilmu Pengetahuan Indonesia
Fondo de Cooperación Internacional en Ciencia y Tecnología
Universidade Federal do Rio Grande do Sul
Österreichischen Akademie der Wissenschaften
Centro Fermi-Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi and Istituto Nazionale di Fisica Nucleare
University Grants Commission, Government of India
National Research Foundation
Ministerstwo Edukacji i Nauki
Ministry of Higher Education and Scientific Research
CERN
Joint Institute for Nuclear Research
Nuclear Physics
Vetenskapsrådet
Österreichische Nationalstiftung für Forschung, Technologie und Entwicklung
Ministry of Education, Culture, Sports, Science and Technology
National Natural Science Foundation of China
Japan Society for the Promotion of Science	20H05638
Japan Society for the Promotion of Science
Austrian Science Fund	M 2467-N36
Austrian Science Fund

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10.1103/PhysRevLett.126.162001

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@article{f749e5f1831543a0a91ac01f03fc5376,

title = "Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sNN =5.02 TeV",

abstract = "The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sNN=5.02 TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v2. The v2 coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (pT) range 1.3-6 GeV/c in the centrality class 30%-50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length cτ≈500 μm compared to that of charm hadrons and most of the other background sources. The v2 of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75 σ. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high pT, but is in agreement with the results at low pT. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.",

author = "{(ALICE Collaboration)} and S. Acharya and D. Adamov{\'a} and A. Adler and J. Adolfsson and Aggarwal, {M. M.} and {Aglieri Rinella}, G. and M. Agnello and N. Agrawal and Z. Ahammed and S. Ahmad and Ahn, {S. U.} and Z. Akbar and A. Akindinov and M. Al-Turany and Alam, {S. N.} and Albuquerque, {D. S.D.} and D. Aleksandrov and B. Alessandro and Alfanda, {H. M.} and {Alfaro Molina}, R. and B. Ali and Y. Ali and A. Alici and N. Alizadehvandchali and A. Alkin and J. Alme and T. Alt and L. Altenkamper and I. Altsybeev and Anaam, {M. N.} and C. Andrei and D. Andreou and A. Andronic and M. Angeletti and V. Anguelov and C. Anson and T. Anti{\v c}i{\'c} and F. Antinori and P. Antonioli and N. Apadula and L. Aphecetche and H. Appelsh{\"a}user and S. Arcelli and R. Arnaldi and M. Arratia and Arsene, {I. C.} and M. Arslandok and F. Bock and Read, {K. F.} and Schmidt, {N. V.}",

note = "Publisher Copyright: {\textcopyright} 2021 CERN.",

year = "2021",

month = apr,

day = "19",

doi = "10.1103/PhysRevLett.126.162001",

language = "English",

volume = "126",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "16",

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TY - JOUR

T1 - Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sNN =5.02 TeV

AU - (ALICE Collaboration)

AU - Acharya, S.

AU - Adamová, D.

AU - Adler, A.

AU - Adolfsson, J.

AU - Aggarwal, M. M.

AU - Aglieri Rinella, G.

AU - Agnello, M.

AU - Agrawal, N.

AU - Ahammed, Z.

AU - Ahmad, S.

AU - Ahn, S. U.

AU - Akbar, Z.

AU - Akindinov, A.

AU - Al-Turany, M.

AU - Alam, S. N.

AU - Albuquerque, D. S.D.

AU - Aleksandrov, D.

AU - Alessandro, B.

AU - Alfanda, H. M.

AU - Alfaro Molina, R.

AU - Ali, B.

AU - Ali, Y.

AU - Alici, A.

AU - Alizadehvandchali, N.

AU - Alkin, A.

AU - Alme, J.

AU - Alt, T.

AU - Altenkamper, L.

AU - Altsybeev, I.

AU - Anaam, M. N.

AU - Andrei, C.

AU - Andreou, D.

AU - Andronic, A.

AU - Angeletti, M.

AU - Anguelov, V.

AU - Anson, C.

AU - Antičić, T.

AU - Antinori, F.

AU - Antonioli, P.

AU - Apadula, N.

AU - Aphecetche, L.

AU - Appelshäuser, H.

AU - Arcelli, S.

AU - Arnaldi, R.

AU - Arratia, M.

AU - Arsene, I. C.

AU - Arslandok, M.

AU - Bock, F.

AU - Read, K. F.

AU - Schmidt, N. V.

PY - 2021/4/19

Y1 - 2021/4/19

N2 - The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sNN=5.02 TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v2. The v2 coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (pT) range 1.3-6 GeV/c in the centrality class 30%-50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length cτ≈500 μm compared to that of charm hadrons and most of the other background sources. The v2 of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75 σ. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high pT, but is in agreement with the results at low pT. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.

AB - The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sNN=5.02 TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v2. The v2 coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (pT) range 1.3-6 GeV/c in the centrality class 30%-50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length cτ≈500 μm compared to that of charm hadrons and most of the other background sources. The v2 of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75 σ. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high pT, but is in agreement with the results at low pT. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.

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U2 - 10.1103/PhysRevLett.126.162001

DO - 10.1103/PhysRevLett.126.162001

M3 - Article

C2 - 33961482

AN - SCOPUS:85105687703

SN - 0031-9007

VL - 126

JO - Physical Review Letters

JF - Physical Review Letters

IS - 16

M1 - 162001

ER -

Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sNN =5.02 TeV

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Funding

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