Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at √sNN=2.76 TeV

ALICE Collaboration

doi:10.1016/j.physletb.2015.12.082

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at √sNN=2.76 TeV

ALICE Collaboration

Relativistic Nuclear Physics

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48 Scopus citations

Abstract

The centrality dependence of the charged-particle pseudorapidity density measured with ALICE in Pb-Pb collisions at √sNN=2.76 TeV over a broad pseudorapidity range is presented. This Letter extends the previous results reported by ALICE to more peripheral collisions. No strong change of the overall shape of charged-particle pseudorapidity density distributions with centrality is observed, and when normalised to the number of participating nucleons in the collisions, the evolution over pseudorapidity with centrality is likewise small. The broad pseudorapidity range (-3.5<η<5) allows precise estimates of the total number of produced charged particles which we find to range from 162±22(syst.) to 17170±770(syst.) in 80-90% and 0-5% central collisions, respectively. The total charged-particle multiplicity is seen to approximately scale with the number of participating nucleons in the collision. This suggests that hard contributions to the charged-particle multiplicity are limited. The results are compared to models which describe dN_ch/dη at mid-rapidity in the most central Pb-Pb collisions and it is found that these models do not capture all features of the distributions.

Original language	English
Pages (from-to)	373-385
Number of pages	13
Journal	Physics Letters B
Volume	754
DOIs	https://doi.org/10.1016/j.physletb.2015.12.082
State	Published - Mar 10 2016

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: State Committee of Science, World Federation of Scientists (WFS) and Swiss Fonds Kidagan, Armenia ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); National Natural Science Foundation of China (NSFC), the Chinese Ministry of Education (CMOE) and the Ministry of Science and Technology of China (MSTC) ; Ministry of Education and Youth of the Czech Republic ; Danish Natural Science Research Council , the Carlsberg Foundation and the Danish National Research Foundation ; The European Research Council under the European Community's Seventh Framework Programme ; Helsinki Institute of Physics and the Academy of Finland ; French CNRS-IN2P3 , the ‘ Region Pays de Loire ’, ‘ Region Alsace ’, ‘ Region Auvergne ’ and CEA , France; German Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie ( BMBF ) and the Helmholtz Association ; General Secretariat for Research and Technology, Ministry of Development, Greece ; National Research, Development and Innovation Office (NKFIH), Hungary ; Department of Atomic Energy and Department of Science and Technology of the Government of India ; Istituto Nazionale di Fisica Nucleare (INFN) and Centro Fermi–Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Italy ; Japan Society for the Promotion of Science (JSPS) KAKENHI and MEXT , Japan; Joint Institute for Nuclear Research, Dubna ; National Research Foundation of Korea (NRF); Consejo Nacional de Cienca y Tecnologia ( CONACYT ), Direccion General de Asuntos del Personal Academico ( Dirección General Asuntos del Personal Académico, Universidad Nacional Autónoma de México ), México, Amerique Latine Formation academique–European Commission (ALFA-EC) and the EPLANET Program (European Particle Physics Latin American Network); Stichting voor Fundamenteel Onderzoek der Materie (FOM) and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; Research Council of Norway (NFR); National Science Centre , Poland; Ministry of National Education/Institute for Atomic Physics and National Council of Scientific Research in Higher Education (CNCSI-UEFISCDI), Romania; Ministry of Education and Science of Russian Federation , Russian Academy of Sciences , Russian Federal Agency of Atomic Energy , Russian Federal Agency for Science and Innovations and The Russian Foundation for Basic Research ; Ministry of Education of Slovakia ; Department of Science and Technology, South Africa ; Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT) , E-Infrastructure shared between Europe and Latin America (EELA) , Ministerio de Economía y Competitividad (MINECO) of Spain, Xunta de Galicia (Consellería de Educación) , Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN) , Cubaenergía , Cuba, and IAEA (International Atomic Energy Agency); Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW); Ukraine Ministry of Education and Science ; United Kingdom Science and Technology Facilities Council ( STFC ); The United States Department of Energy , the United States National Science Foundation , the State of Texas , and the State of Ohio ; Ministry of Science, Education and Sports of Croatia and Unity through Knowledge Fund, Croatia ; Council of Scientific and Industrial Research (CSIR), New Delhi, India; Pontificia Universidad Católica del Perú . 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: State Committee of Science, World Federation of Scientists (WFS) and Swiss Fonds Kidagan, Armenia; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); National Natural Science Foundation of China (NSFC), the Chinese Ministry of Education (CMOE) and the Ministry of Science and Technology of China (MSTC); Ministry of Education and Youth of the Czech Republic; Danish Natural Science Research Council, the Carlsberg Foundation and the Danish National Research Foundation; The European Research Council under the European Community''s Seventh Framework Programme; Helsinki Institute of Physics and the Academy of Finland; French CNRS-IN2P3, the ‘Region Pays de Loire’, ‘Region Alsace’, ‘Region Auvergne’ and CEA, France; German Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie (BMBF) and the Helmholtz Association; General Secretariat for Research and Technology, Ministry of Development, Greece; National Research, Development and Innovation Office (NKFIH), Hungary; Department of Atomic Energy and Department of Science and Technology of the Government of India; Istituto Nazionale di Fisica Nucleare (INFN) and Centro Fermi–Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Italy; Japan Society for the Promotion of Science (JSPS) KAKENHI and MEXT, Japan; Joint Institute for Nuclear Research, Dubna; National Research Foundation of Korea (NRF); Consejo Nacional de Cienca y Tecnologia (CONACYT), Direccion General de Asuntos del Personal Academico (Dirección General Asuntos del Personal Académico, Universidad Nacional Autónoma de México), México, Amerique Latine Formation academique–European Commission (ALFA-EC) and the EPLANET Program (European Particle Physics Latin American Network); Stichting voor Fundamenteel Onderzoek der Materie (FOM) and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; Research Council of Norway (NFR); National Science Centre, Poland; Ministry of National Education/Institute for Atomic Physics and National Council of Scientific Research in Higher Education (CNCSI-UEFISCDI), Romania; Ministry of Education and Science of Russian Federation, Russian Academy of Sciences, Russian Federal Agency of Atomic Energy, Russian Federal Agency for Science and Innovations and The Russian Foundation for Basic Research; Ministry of Education of Slovakia; Department of Science and Technology, South Africa; Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), E-Infrastructure shared between Europe and Latin America (EELA), Ministerio de Economía y Competitividad (MINECO) of Spain, Xunta de Galicia (Consellería de Educación), Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Cubaenergía, Cuba, and IAEA (International Atomic Energy Agency); Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW); Ukraine Ministry of Education and Science; United Kingdom Science and Technology Facilities Council (STFC); The United States Department of Energy, the United States National Science Foundation, the State of Texas, and the State of Ohio; Ministry of Science, Education and Sports of Croatia and Unity through Knowledge Fund, Croatia; Council of Scientific and Industrial Research (CSIR), New Delhi, India; Pontificia Universidad Católica del Perú.

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10.1016/j.physletb.2015.12.082

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@article{51d734e71b654aa796c8c5b60269fd00,

title = "Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at √sNN=2.76 TeV",

abstract = "The centrality dependence of the charged-particle pseudorapidity density measured with ALICE in Pb-Pb collisions at √sNN=2.76 TeV over a broad pseudorapidity range is presented. This Letter extends the previous results reported by ALICE to more peripheral collisions. No strong change of the overall shape of charged-particle pseudorapidity density distributions with centrality is observed, and when normalised to the number of participating nucleons in the collisions, the evolution over pseudorapidity with centrality is likewise small. The broad pseudorapidity range (-3.5<η<5) allows precise estimates of the total number of produced charged particles which we find to range from 162±22(syst.) to 17170±770(syst.) in 80-90% and 0-5% central collisions, respectively. The total charged-particle multiplicity is seen to approximately scale with the number of participating nucleons in the collision. This suggests that hard contributions to the charged-particle multiplicity are limited. The results are compared to models which describe dNch/dη at mid-rapidity in the most central Pb-Pb collisions and it is found that these models do not capture all features of the distributions.",

author = "{ALICE Collaboration} and J. Adam and D. Adamov{\'a} and Aggarwal, {M. M.} and {Aglieri Rinella}, G. and M. Agnello and N. Agrawal and Z. Ahammed and Ahn, {S. U.} and S. Aiola and A. Akindinov and Alam, {S. N.} and D. Aleksandrov and B. Alessandro and D. Alexandre and {Alfaro Molina}, R. and A. Alici and A. Alkin and Almaraz, {J. R.M.} and J. Alme and T. Alt and S. Altinpinar and I. Altsybeev and {Alves Garcia Prado}, C. and C. Andrei and A. Andronic and V. Anguelov and J. Anielski and T. Anti{\v c}i{\'c} and F. Antinori and P. Antonioli and L. Aphecetche and H. Appelsh{\"a}user and S. Arcelli and R. Arnaldi and Arnold, {O. W.} and Arsene, {I. C.} and M. Arslandok and B. Audurier and A. Augustinus and R. Averbeck and Azmi, {M. D.} and A. Badal{\`a} and Baek, {Y. W.} and S. Bagnasco and R. Bailhache and R. Bala and A. Baldisseri and Baral, {R. C.} and F. Bock and Read, {K. F.}",

note = "Publisher Copyright: {\textcopyright} 2016 CERN for the benefit of the ALICE Collaboration.",

year = "2016",

month = mar,

day = "10",

doi = "10.1016/j.physletb.2015.12.082",

language = "English",

volume = "754",

pages = "373--385",

journal = "Physics Letters B",

issn = "0370-2693",

publisher = "Elsevier",

}

TY - JOUR

T1 - Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at √sNN=2.76 TeV

AU - ALICE Collaboration

AU - Adam, J.

AU - Adamová, D.

AU - Aggarwal, M. M.

AU - Aglieri Rinella, G.

AU - Agnello, M.

AU - Agrawal, N.

AU - Ahammed, Z.

AU - Ahn, S. U.

AU - Aiola, S.

AU - Akindinov, A.

AU - Alam, S. N.

AU - Aleksandrov, D.

AU - Alessandro, B.

AU - Alexandre, D.

AU - Alfaro Molina, R.

AU - Alici, A.

AU - Alkin, A.

AU - Almaraz, J. R.M.

AU - Alme, J.

AU - Alt, T.

AU - Altinpinar, S.

AU - Altsybeev, I.

AU - Alves Garcia Prado, C.

AU - Andrei, C.

AU - Andronic, A.

AU - Anguelov, V.

AU - Anielski, J.

AU - Antičić, T.

AU - Antinori, F.

AU - Antonioli, P.

AU - Aphecetche, L.

AU - Appelshäuser, H.

AU - Arcelli, S.

AU - Arnaldi, R.

AU - Arnold, O. W.

AU - Arsene, I. C.

AU - Arslandok, M.

AU - Audurier, B.

AU - Augustinus, A.

AU - Averbeck, R.

AU - Azmi, M. D.

AU - Badalà, A.

AU - Baek, Y. W.

AU - Bagnasco, S.

AU - Bailhache, R.

AU - Bala, R.

AU - Baldisseri, A.

AU - Baral, R. C.

AU - Bock, F.

AU - Read, K. F.

PY - 2016/3/10

Y1 - 2016/3/10

N2 - The centrality dependence of the charged-particle pseudorapidity density measured with ALICE in Pb-Pb collisions at √sNN=2.76 TeV over a broad pseudorapidity range is presented. This Letter extends the previous results reported by ALICE to more peripheral collisions. No strong change of the overall shape of charged-particle pseudorapidity density distributions with centrality is observed, and when normalised to the number of participating nucleons in the collisions, the evolution over pseudorapidity with centrality is likewise small. The broad pseudorapidity range (-3.5<η<5) allows precise estimates of the total number of produced charged particles which we find to range from 162±22(syst.) to 17170±770(syst.) in 80-90% and 0-5% central collisions, respectively. The total charged-particle multiplicity is seen to approximately scale with the number of participating nucleons in the collision. This suggests that hard contributions to the charged-particle multiplicity are limited. The results are compared to models which describe dNch/dη at mid-rapidity in the most central Pb-Pb collisions and it is found that these models do not capture all features of the distributions.

AB - The centrality dependence of the charged-particle pseudorapidity density measured with ALICE in Pb-Pb collisions at √sNN=2.76 TeV over a broad pseudorapidity range is presented. This Letter extends the previous results reported by ALICE to more peripheral collisions. No strong change of the overall shape of charged-particle pseudorapidity density distributions with centrality is observed, and when normalised to the number of participating nucleons in the collisions, the evolution over pseudorapidity with centrality is likewise small. The broad pseudorapidity range (-3.5<η<5) allows precise estimates of the total number of produced charged particles which we find to range from 162±22(syst.) to 17170±770(syst.) in 80-90% and 0-5% central collisions, respectively. The total charged-particle multiplicity is seen to approximately scale with the number of participating nucleons in the collision. This suggests that hard contributions to the charged-particle multiplicity are limited. The results are compared to models which describe dNch/dη at mid-rapidity in the most central Pb-Pb collisions and it is found that these models do not capture all features of the distributions.

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U2 - 10.1016/j.physletb.2015.12.082

DO - 10.1016/j.physletb.2015.12.082

M3 - Article

AN - SCOPUS:84999274063

SN - 0370-2693

VL - 754

SP - 373

EP - 385

JO - Physics Letters B

JF - Physics Letters B

ER -

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at √sNN=2.76 TeV

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