Evidence for collectivity in pp collisions at the LHC

CMS Collaboration

doi:10.1016/j.physletb.2016.12.009

Evidence for collectivity in pp collisions at the LHC

CMS Collaboration

Department of Physics Engineering

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

302 Citations (SciVal)

Abstract

Measurements of two- and multi-particle angular correlations in pp collisions at s=5,7, and 13TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0pb⁻¹ (5 TeV), 6.2pb⁻¹ (7 TeV), and 0.7pb⁻¹ (13 TeV), were collected using the CMS detector at the LHC. The second-order (v₂) and third-order (v₃) azimuthal anisotropy harmonics of unidentified charged particles, as well as v₂ of K_S ⁰ and Λ/Λ‾ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v₂ values of charged hadrons (mostly pions), K_S ⁰, and Λ/Λ‾, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below p_T≈2GeV/c. For 13 TeV data, the v₂ signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.

Original language	English
Pages (from-to)	193-220
Number of pages	28
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	765
DOIs	https://doi.org/10.1016/j.physletb.2016.12.009
Publication status	Published - 10 Feb 2017

Bibliographical note

Publisher Copyright:
© 2016 The Author

Funding

Individuals have received support from the Marie-Curie program and the European Research Council and EPLANET (European Union); the Leventis Foundation; the Alfred P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Council of Science and Industrial Research, India; the HOMING PLUS program of the Foundation for Polish Science, cofinanced from European Union, Regional Development Fund, the Mobility Plus program of the Ministry of Science and Higher Education, the OPUS program contract 2014/13/B/ST2/02543 and contract Sonata-bis DEC-2012/07/E/ST2/01406 of the National Science Center (Poland); the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF; the National Priorities Research Program by Qatar National Research Fund; the Programa Clarín-COFUND del Principado de Asturias; the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University and the Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand); and the Welch Foundation, contract C-1845.

Funders	Funder number
EU-ESF
National Science Foundation	1606321, 1151640, 1506168, 1506130, 1120138, 1211067, 1624356, 1508869
Alfred P. Sloan Foundation
Welch Foundation	C-1845
Alexander von Humboldt-Stiftung
Qatar National Research Fund
Ministry of Education and Science	2014/13/B/ST2/02543, DEC-2012/07/E/ST2/01406
Science and Technology Facilities Council	ST/N000250/1, ST/K001256/1, GRIDPP
European Commission
European Research Council
Council of Scientific and Industrial Research, India
Ministerstvo Školství, Mládeže a Tělovýchovy
Fundacja na rzecz Nauki Polskiej
Belgian Federal Science Policy Office
Chulalongkorn University
Agentschap voor Innovatie door Wetenschap en Technologie
Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture
A.G. Leventis Foundation
Narodowe Centrum Nauki
European Regional Development Fund

Keywords

CMS
Correlation
Heavy ion
Physics
Ridge
pp

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10.1016/j.physletb.2016.12.009

Cite this

@article{00514d2a0cc648f8a9dc97d3967d4fe9,

title = "Evidence for collectivity in pp collisions at the LHC",

abstract = "Measurements of two- and multi-particle angular correlations in pp collisions at s=5,7, and 13TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0pb−1 (5 TeV), 6.2pb−1 (7 TeV), and 0.7pb−1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of KS 0 and Λ/Λ‾ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), KS 0, and Λ/Λ‾, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT≈2GeV/c. For 13 TeV data, the v2 signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.",

keywords = "CMS, Correlation, Heavy ion, Physics, Ridge, pp",

author = "{CMS Collaboration} and Sirunyan, {A. M.} and A. Tumasyan and W. Adam and T. Bergauer and M. Dragicevic and J. Er{\"o} and {Escalante Del Valle}, A. and R. Fr{\"u}hwirth and M. Jeitler and N. Krammer and L. Lechner and D. Liko and T. Madlener and I. Mikulec and Pitters, {F. M.} 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. Chekhovsky and A. Litomin and V. Makarenko and {Suarez Gonzalez}, J. 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 {Rejeb Sfar}, H. 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{\textquoteright}Hondt and {de Clercq}, J. and D. Lontkovskyi and S. Lowette and I. Marchesini and S. Moortgat and A. Morton and A. Cakir",

note = "Publisher Copyright: {\textcopyright} 2016 The Author",

year = "2017",

month = feb,

day = "10",

doi = "10.1016/j.physletb.2016.12.009",

language = "English",

volume = "765",

pages = "193--220",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier B.V.",

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TY - JOUR

T1 - Evidence for collectivity in pp collisions at the LHC

AU - CMS Collaboration

AU - Sirunyan, A. M.

AU - Tumasyan, A.

AU - Adam, W.

AU - Bergauer, T.

AU - Dragicevic, M.

AU - Erö, J.

AU - Escalante Del Valle, A.

AU - Frühwirth, R.

AU - Jeitler, M.

AU - Krammer, N.

AU - Lechner, L.

AU - Liko, D.

AU - Madlener, T.

AU - Mikulec, I.

AU - Pitters, F. M.

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 - Chekhovsky, V.

AU - Litomin, A.

AU - Makarenko, V.

AU - Suarez Gonzalez, J.

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 - Rejeb Sfar, H.

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 - Lontkovskyi, D.

AU - Lowette, S.

AU - Marchesini, I.

AU - Moortgat, S.

AU - Morton, A.

AU - Cakir, A.

PY - 2017/2/10

Y1 - 2017/2/10

N2 - Measurements of two- and multi-particle angular correlations in pp collisions at s=5,7, and 13TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0pb−1 (5 TeV), 6.2pb−1 (7 TeV), and 0.7pb−1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of KS 0 and Λ/Λ‾ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), KS 0, and Λ/Λ‾, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT≈2GeV/c. For 13 TeV data, the v2 signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.

AB - Measurements of two- and multi-particle angular correlations in pp collisions at s=5,7, and 13TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0pb−1 (5 TeV), 6.2pb−1 (7 TeV), and 0.7pb−1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of KS 0 and Λ/Λ‾ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), KS 0, and Λ/Λ‾, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT≈2GeV/c. For 13 TeV data, the v2 signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.

KW - CMS

KW - Correlation

KW - Heavy ion

KW - Physics

KW - Ridge

KW - pp

UR - http://www.scopus.com/inward/record.url?scp=85007251845&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2016.12.009

DO - 10.1016/j.physletb.2016.12.009

M3 - Article

AN - SCOPUS:85007251845

SN - 0370-2693

VL - 765

SP - 193

EP - 220

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

ER -

Evidence for collectivity in pp collisions at the LHC

Abstract

Bibliographical note

Funding

Keywords

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