skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Importance of non-flow in mixed-harmonic multi-particle correlations in small collision systems

Abstract

Recently CMS Collaboration measured mixed-harmonic four-particle azimuthal correlations, known as symmetric cumulants SC(n, m), in pp and p+Pb collisions, and interpreted the non-zero SC(n, m) as evidence for long-range collectivity in these small collision systems. Using the PYTHIA and HIJING models which do not have genuine long-range collectivity, we show that the CMS results, obtained with standard cumulant method, could be dominated by non-flow effects associated with jet and dijets, especially in pp collisions. We show that the non-flow effects are largely suppressed using the recently proposed subevent cumulant methods by requiring azimuthal correlation between two or more pseudorapidity ranges. As a result, we argue that the reanalysis of SC(n, m) using the subevent method in experiments is necessary before they can used to provide further evidences for a long-range multi-particle collectivity and constraints on theoretical models in small collision systems.

Authors:
 [1];  [2]; ORCiD logo [3]; ORCiD logo [2]
  1. Stony Brook Univ., Stony Brook, NY (United States)
  2. Univ. of Copenhagen, Copenhagen (Denmark)
  3. Stony Brook Univ., Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP)
OSTI Identifier:
1439313
Report Number(s):
BNL-205708-2018-JAAM
Journal ID: ISSN 0370-2693; TRN: US1900601
Grant/Contract Number:  
SC0012704
Resource Type:
Accepted Manuscript
Journal Name:
Physics Letters B
Additional Journal Information:
Journal Volume: 777; Journal Issue: C; Journal ID: ISSN 0370-2693
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS

Citation Formats

Huo, Peng, Gajdosova, Katarina, Jia, Jiangyong, and Zhou, You. Importance of non-flow in mixed-harmonic multi-particle correlations in small collision systems. United States: N. p., 2017. Web. https://doi.org/10.1016/j.physletb.2017.12.035.
Huo, Peng, Gajdosova, Katarina, Jia, Jiangyong, & Zhou, You. Importance of non-flow in mixed-harmonic multi-particle correlations in small collision systems. United States. https://doi.org/10.1016/j.physletb.2017.12.035
Huo, Peng, Gajdosova, Katarina, Jia, Jiangyong, and Zhou, You. Mon . "Importance of non-flow in mixed-harmonic multi-particle correlations in small collision systems". United States. https://doi.org/10.1016/j.physletb.2017.12.035. https://www.osti.gov/servlets/purl/1439313.
@article{osti_1439313,
title = {Importance of non-flow in mixed-harmonic multi-particle correlations in small collision systems},
author = {Huo, Peng and Gajdosova, Katarina and Jia, Jiangyong and Zhou, You},
abstractNote = {Recently CMS Collaboration measured mixed-harmonic four-particle azimuthal correlations, known as symmetric cumulants SC(n, m), in pp and p+Pb collisions, and interpreted the non-zero SC(n, m) as evidence for long-range collectivity in these small collision systems. Using the PYTHIA and HIJING models which do not have genuine long-range collectivity, we show that the CMS results, obtained with standard cumulant method, could be dominated by non-flow effects associated with jet and dijets, especially in pp collisions. We show that the non-flow effects are largely suppressed using the recently proposed subevent cumulant methods by requiring azimuthal correlation between two or more pseudorapidity ranges. As a result, we argue that the reanalysis of SC(n, m) using the subevent method in experiments is necessary before they can used to provide further evidences for a long-range multi-particle collectivity and constraints on theoretical models in small collision systems.},
doi = {10.1016/j.physletb.2017.12.035},
journal = {Physics Letters B},
number = C,
volume = 777,
place = {United States},
year = {2017},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 9 works
Citation information provided by
Web of Science

Figures / Tables:

Figure 1 Figure 1: The SC(n,m) calculated for charged particles with 0.3 < pT < 3 GeV with the standard cumulant method in 13 TeV pp collisions (left panel) and 5.02 TeV p+Pb collisions (right panel) compared between data (solid symbols) and Monte Carlo models (open symbols).

Save / Share:

Works referenced in this record:

Observation of long-range, near-side angular correlations in pPb collisions at the LHC
journal, January 2013


Long-range angular correlations on the near and away side in p–Pb collisions at <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msqrt><mml:msub><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">NN</mml:mi></mml:mrow></mml:msub></mml:msqrt><mml:mo>=</mml:mo><mml:mn>5.02</mml:mn><mml:mtext> TeV</mml:mtext></mml:math>
journal, February 2013


Collective dynamics in high-energy proton-nucleus collisions
journal, July 2013


New method for measuring azimuthal distributions in nucleus-nucleus collisions
journal, April 2001


Generic framework for anisotropic flow analyses with multiparticle azimuthal correlations
journal, June 2014

  • Bilandzic, Ante; Christensen, Christian Holm; Gulbrandsen, Kristjan
  • Physical Review C, Vol. 89, Issue 6
  • DOI: 10.1103/PhysRevC.89.064904

Flow analysis from multiparticle azimuthal correlations
journal, September 2001


Evidence for collectivity in pp collisions at the LHC
journal, February 2017


Measurement of multi-particle azimuthal correlations in pp, p + Pb and low-multiplicity Pb + Pb collisions with the ATLAS detector
journal, June 2017


A brief introduction to PYTHIA 8.1
journal, June 2008

  • Sjöstrand, Torbjörn; Mrenna, Stephen; Skands, Peter
  • Computer Physics Communications, Vol. 178, Issue 11
  • DOI: 10.1016/j.cpc.2008.01.036

HIJING 1.0: A Monte Carlo program for parton and particle production in high energy hadronic and nuclear collisions
journal, December 1994


    Works referencing / citing this record:

    Centrality fluctuations in heavy-ion collisions
    journal, October 2018


    Multiparticle azimuthal cumulants in p + Pb collisions from a multiphase transport model
    journal, September 2018


    CERN Large Hadron Collider system size scan predictions for PbPb, XeXe, ArAr, and OO with relativistic hydrodynamics
    journal, August 2019


    Investigations of Anisotropic Flow Using Multiparticle Azimuthal Correlations in $pp$, $p-Pb$, Xe-Xe, and Pb-Pb Collisions at the LHC
    text, January 2019

    • Acharya, Shreyasi; Adamova, Dagmar; Adhya, Souvik Priyam
    • GSI Helmholtzzentrum fuer Schwerionenforschung, GSI, Darmstadt
    • DOI: 10.15120/gsi-2020-00125

    Investigations of Anisotropic Flow Using Multiparticle Azimuthal Correlations in p p , p Pb , Xe-Xe, and Pb-Pb Collisions at the LHC
    journal, October 2019


      Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.