The fluctuations of quadrangular flow

Giacalone, Giuliano; Yan, Li; Noronha-Hostler, Jacquelyn; Ollitrault, Jean-Yves

doi:10.1088/1742-6596/779/1/012064

Cited by 8 publications

(9 citation statements)

References 38 publications

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“…Previous measurements [13,14] show that the V 4L term dominates in central collisions, while the V 2 2 term dominates in more peripheral collisions. Therefore, the sign change of nc 4 {4} could reflect an interplay between these two contributions [71]. In central collisions, nc 4 {4} is dominated by a negative contribution from p(v 4L ), while in peripheral collisions nc 4 {4} is dominated by a positive contribution from p(v 2 2 ).…”

Section: Jhep01(2020)051mentioning

confidence: 99%

Fluctuations of anisotropic flow in Pb+Pb collisions at $$ \sqrt{{\mathrm{s}}_{\mathrm{NN}}} $$ = 5.02 TeV with the ATLAS detector

Aaboud

Aad

Abbott

et al. 2020

J. High Energ. Phys.

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Multi-particle azimuthal cumulants are measured as a function of centrality and transverse momentum using 470 µb −1 of Pb+Pb collisions at √ s NN = 5.02 TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-byevent fluctuations of harmonic flow coefficients v n and correlated fluctuations between two harmonics v n and v m. For the first time, a non-zero four-particle cumulant is observed for dipolar flow, v 1. The four-particle cumulants for elliptic flow, v 2 , and triangular flow, v 3 , exhibit a strong centrality dependence and change sign in ultra-central collisions. This sign change is consistent with significant non-Gaussian fluctuations in v 2 and v 3. The four-particle cumulant for quadrangular flow, v 4 , is found to change sign in mid-central collisions. Correlations between two harmonics are studied with three-and four-particle mixed-harmonic cumulants, which indicate an anti-correlation between v 2 and v 3 , and a positive correlation between v 2 and v 4. These correlations decrease in strength towards central collisions and either approach zero or change sign in ultra-central collisions. To investigate the possible flow fluctuations arising from intrinsic centrality or volume fluctuations, the results are compared between two different event classes used for centrality definitions. In peripheral and mid-central collisions where the cumulant signals are large, only small differences are observed. In ultra-central collisions, the differences are much larger and transverse momentum dependent. These results provide new information to disentangle flow fluctuations from the initial and final states, as well as new insights on the influence of centrality fluctuations.

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Section: Jhep01(2020)051mentioning

confidence: 99%

Fluctuations of anisotropic flow in Pb+Pb collisions at $$ \sqrt{{\mathrm{s}}_{\mathrm{NN}}} $$ = 5.02 TeV with the ATLAS detector

Aaboud

Aad

Abbott

et al. 2020

J. High Energ. Phys.

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“…Since the discovery of triangular flow and the advent of event-by-event hydrodynamic simulations (for a review see [68]), a large body of research has been developed on the subject of flow fluctuations, e.g., [40,61,62,[69][70][71][72][73]. Within a set centrality class a wide distribution of flow harmonics are measured by ATLAS [74] wherein one can then describe the moments of the distribution via multiparticle cumulants:…”

Section: Flow Fluctuationsmentioning

confidence: 99%

“…12 (v 4 {4}) 4 is shown for both RHIC and LHC run 2. Here we do not plot v 4 {4} directly because it changes sign [72], which would lead to imaginary numbers in central collisions. As in [72], we see a sign change around ∼ 40% centrality for both energies.…”

Section: Flow Fluctuationsmentioning

confidence: 99%

“…Here we do not plot v 4 {4} directly because it changes sign [72], which would lead to imaginary numbers in central collisions. As in [72], we see a sign change around ∼ 40% centrality for both energies. It does appear that this quantity depends on the choice of the equation of state at LHC run 2 though more statistics are needed to be certain.…”

Section: Flow Fluctuationsmentioning

confidence: 99%

“…Interestingly enough, experi-ments also see a change in sign but this occurs closer to 20% centrality [79] so a puzzle still remains. We note that this quantity has both linear and nonlinear contributions but the linear part is more dampened by viscosity so this could be used to constrain the temperature dependence of η/s [72], although the high statistics needed for this observable requires significant computational resources that go beyond the scope of the present work.…”

Section: Flow Fluctuationsmentioning

confidence: 99%

See 2 more Smart Citations

Effect of the QCD equation of state and strange hadronic resonances on multiparticle correlations in heavy ion collisions

et al. 2018

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The QCD equation of state at zero baryon chemical potential is the only element of the standard dynamical framework to describe heavy ion collisions that can be directly determined from first principles. Continuum extrapolated lattice QCD equations of state have been computed using 2+1 quark flavors (up/down and strange) as well as 2+1+1 flavors to investigate the effect of thermalized charm quarks on QCD thermodynamics. Lattice results have also indicated the presence of new strange resonances that not only contribute to the equation of state of QCD matter but also affect hadronic afterburners used to model the later stages of heavy ion collisions. We investigate how these new developments obtained from first principles calculations affect multiparticle correlations in heavy ion collisions. We compare the commonly used equation of state S95n-v1, which was constructed using what are now considered outdated lattice results and hadron states, to the current state-of-the-art lattice QCD equations of state with 2+1 and 2+1+1 flavors coupled to the most upto-date hadronic resonances and their decays. New hadronic resonances lead to an enhancement in the hadronic spectra at intermediate pT . Using an outdated equation of state can directly affect the extraction of the shear viscosity to entropy density ratio, η/s, of the quark-gluon plasma and results for different flow observables. The effects of the QCD equation of state on multiparticle correlations of identified particles are determined for both AuAu √ sNN = 200 GeV and PbPb √ sNN = 5.02 TeV collisions. New insights into the v2{2} to v3{2} puzzle in ultracentral collisions are found. Flow observables of heavier particles exhibit more non-linear behavior regardless of the assumptions about the equation of state, which may provide a new way to constrain the temperature dependence of η/s.

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Jet modifications in event-by-event hydrodynamically evolving media

Noronha-Hostler

2017

Nuclear Physics A

Self Cite

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The nearly perfect fluid-like nature of the Quark Gluon Plasma may be understood through two key experimental signatures: collective flow and jet suppression. Event-by-event relativistic viscous hydrodynamics (with an extremely small shear viscosity to entropy density ratio) has been very successful at describing collective flow observables for the last 7 years. More recently, the effects of event-by-event fluctuations have been studied in the context of high p T particles that lose energy as they pass through the dense Quark Gluon Plasma liquid. In this summary of the corresponding plenary talk at Quark Matter 2017, the recent developments on the effects of event-by-event fluctuations on jet suppression are summarized.

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The fluctuations of quadrangular flow

Cited by 8 publications

References 38 publications

Fluctuations of anisotropic flow in Pb+Pb collisions at $$ \sqrt{{\mathrm{s}}_{\mathrm{NN}}} $$ = 5.02 TeV with the ATLAS detector

Fluctuations of anisotropic flow in Pb+Pb collisions at $$ \sqrt{{\mathrm{s}}_{\mathrm{NN}}} $$ = 5.02 TeV with the ATLAS detector

Effect of the QCD equation of state and strange hadronic resonances on multiparticle correlations in heavy ion collisions

Jet modifications in event-by-event hydrodynamically evolving media

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