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Studies of azimuthal dihadron correlations in ultra-central PbPb collisions at $$\sqrt{s_{NN}} =$$ 2.76 TeV

Journal Article · · Journal of High Energy Physics (Online)
 [1]
  1. Yerevan Physics Inst. (YerPhI), Yerevan (Armenia). et al.
Azimuthal dihadron correlations of charged particles have been measured in PbPb collisions at $$\sqrt{s_{NN}}$$ = 2.76 TeV by the CMS collaboration, using data from the 2011 LHC heavy-ion run. The data set includes a sample of ultra-central (0-0.2% centrality) PbPb events collected using a trigger based on total transverse energy in the hadron forward calorimeters and the total multiplicity of pixel clusters in the silicon pixel tracker. A total of about 1.8 million ultra-central events were recorded, corresponding to an integrated luminosity of 120 inverse microbarns. The observed correlations in ultra-central PbPb events are expected to be particularly sensitive to initial-state fluctuations. The single-particle anisotropy Fourier harmonics, from $$v_2$$ to $$v_6$$, are extracted as a function of particle transverse momentum. At higher transverse momentum, the $$v_2$$ harmonic becomes significantly smaller than the higher-order $$v_n$$ (n greater than or equal to 3). The pt-averaged $$v_2$$ and $$v_3$$ are found to be equal within 2%, while higher-order $$v_n$$ decrease as n increases. The breakdown of factorization of dihadron correlations into single-particle azimuthal anisotropies is observed. This effect is found to be most prominent in the ultra-central PbPb collisions, where the initial-state fluctuations play a dominant role. As a result, a comparison of the factorization data to hydrodynamic predictions with event-by-event fluctuating initial conditions is also presented.
Research Organization:
Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Organization:
The CMS Collaboration
Grant/Contract Number:
AC02-07CH11359
OSTI ID:
1151701
Alternate ID(s):
OSTI ID: 22476352
Report Number(s):
FERMILAB-PUB--13-615-CMS; arXiv eprint number arXiv:1312.1845
Journal Information:
Journal of High Energy Physics (Online), Journal Name: Journal of High Energy Physics (Online) Journal Issue: 2 Vol. 2014; ISSN 1029-8479
Publisher:
Springer BerlinCopyright Statement
Country of Publication:
United States
Language:
English

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Event-shape fluctuations and flow correlations in ultra-relativistic heavy-ion collisions journal November 2014
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Simulation studies of R 2 ( Δ η , Δ φ ) and P 2 ( Δ η , Δ φ ) correlation functions in p p collisions with the PYTHIA and HERWIG models journal August 2019
Two-particle differential transverse momentum and number density correlations in p − Pb collisions at 5.02 TeV and Pb-Pb collisions at 2.76 TeV at the CERN Large Hadron Collider journal October 2019
Correlations between azimuthal anisotropy Fourier harmonics in PbPb collisions at s N N = 2.76 TeV in the HYDJET + + model and in the multiphase transport model journal January 2020
Solutions of conformal Israel-Stewart relativistic viscous fluid dynamics journal January 2015
Shape and flow fluctuations in ultracentral Pb + Pb collisions at the energies available at the CERN Large Hadron Collider journal July 2015
Collective flow in event-by-event partonic transport plus hydrodynamics hybrid approach journal July 2015
Measurement of the correlation between flow harmonics of different order in lead-lead collisions at s NN = 2.76 TeV with the ATLAS detector journal September 2015
Evidence for transverse-momentum- and pseudorapidity-dependent event-plane fluctuations in PbPb and p Pb collisions journal September 2015
Event-shape engineering for inclusive spectra and elliptic flow in Pb-Pb collisions at s NN = 2.76 TeV journal March 2016
Applying Bayesian parameter estimation to relativistic heavy-ion collisions: Simultaneous characterization of the initial state and quark-gluon plasma medium journal August 2016
Principal-component analysis of two-particle azimuthal correlations in PbPb and p Pb collisions at CMS journal December 2017
Effect of the QCD equation of state and strange hadronic resonances on multiparticle correlations in heavy ion collisions journal September 2018
Area covered by disks in small-bounded continuum percolating systems: An application to the string percolation model journal August 2019
Evidence for Collective Multiparticle Correlations in p − Pb Collisions journal June 2015
Elliptic Flow of Charm and Strange Hadrons in High-Multiplicity p + Pb Collisions at s NN = 8.16     TeV journal August 2018
Relativistic Hydrodynamics in Heavy-Ion Collisions: General Aspects and Recent Developments journal January 2016
Observation of correlated azimuthal anisotropy Fourier harmonics in pp and pPb collisions at the LHC text January 2017
Measurement of multi-particle azimuthal correlations in pp, p + Pb and low-multiplicity Pb + Pb collisions with the ATLAS detector text January 2017
Measurement of multi-particle azimuthal correlations in $pp$, $p+$Pb and low-multiplicity Pb$+$Pb collisions with the ATLAS detector text January 2017
Elliptic Flow of Charm and Strange Hadrons in High-Multiplicity p+Pb Collisions at √sNN=8.16  TeV text January 2018
Principal-component analysis of two-particle azimuthal correlations in PbPb and pPb collisions at CMS text January 2017

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