E otv os University, BudapestCharged pions !Coulomb interaction !(approx.) Coulomb correction 0-30%...
Transcript of E otv os University, BudapestCharged pions !Coulomb interaction !(approx.) Coulomb correction 0-30%...
Three-dimensional Levy HBT in Au+Au collisionsat PHENIX
Balint Kurgyis
Eotvos University, Budapest
International School of Subnuclear Physics 56th CourseErice 14-23 June 2018
”SUPPORTED BY UNKP-17-1 NEW NATIONAL EXCELLENCE PROGRAMME GRANT”
Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
What are we looking for?
Big bang in the laboratory - heavy-ion collisions
Timeline of the Universe
GalaxiesAtomsNucleiElementary particles
How should we investigate?
Reproduce in the laboratory!
Create “little bangs”
→ Heavy-ion collisions
Detect the created particles
→ Study the sQGP
Balint Kurgyis Eotvos University, Budapest
Three-dimensional Levy HBT 2 / 12
Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
What are we looking for?
The PHENIX experiment
Different collision energies
7.7-200 GeV in√s
NN
20-400 MeV in µB
Different collision systems
p+p, p+A, A+A
This analysis: 200 GeV Au+Au
particle emitting sourcespace-time evolution of sQGP
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Three-dimensional Levy HBT 3 / 12
Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
What are we looking for?
The HBT effect and the Bose-Einstein correlations
R. Hanbury Brown, R. Q. Twiss - radio telescopes
Intensity correlations as function of detector distance→ Measuring the size of the source (Sirius)
Goldhaber et al. - application in high energy physics
Bose-Einstein correlations - momentum correlationsRelated to the source function
C (q) ∼= 1 + |∫S(r)e iqrdr|2, where q = p2 − p1
Measuring momentum correlations → femtoscopic space-time geometry
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Three-dimensional Levy HBT 4 / 12
Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
What are we looking for?
Levy distribution and the shape of the correlation functionExpanding medium → increasing mean free path→ Anomalous diffusion
Levy-stable distribution (generalized cent. lim. theor.)
L(r ;α,R) =1
(2π)3
∫d3qe iqre−
12|qR|α
Power-law tail: ∝ r−1−α
Levy exponent: α (Gaussian: α = 2, Cauchy: α = 1)
Lévy-HBT correlations 4 / 15
Two component source:
Core: thermalized medium, expanding sourceHalo: long lived resonances (τ > 10 fm/c)→ experimentally unresolvable
True q→ 0 limit: C (q = 0) = 2; Experimentally: C (q→ 0) = 1 + λ
Correlation strength: λ =(
NCoreNCore+NHalo
)2
Corr. func.: C (q;R, α, λ) = 1 + λe−|qR|α
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Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
What are we looking for?
The connection of Levy-index and the critical point
Looking for critical behavior with critical exponents
Critical spatial correlation: ∼ r−(d−2−η)
Levy source: ∼ r−(1+α) → η ⇐⇒ α ?Csorgo et al. Eur. Phys. J. C36 67 (2004)
QCD universality class ⇐⇒ 3D IsingHalasz et al., Phys. Rev. D58 096007 (1998)Stephanov et al., Phys. Rev. Let. 81 4816 (1998)
Critical point:
Random field 3D Ising: η = 0.50± 0.05Rieger, Phys. Rev. B52 6659 (1995)
3D Ising: η = 0.03631(3)El-Showk et al., J. Stat. Phys. 157 (4-5):869
Motivation for precise Levy HBT!
Finite size, non-equilibrium effects
What does the power-law tail mean?
Balint Kurgyis Eotvos University, Budapest
Three-dimensional Levy HBT 6 / 12
Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
The results of this work
Three-dimensional correlation functionBertsch-Pratt coordinates (LCMS): q = (qout, qside, qlong)
Identified same charged pion pairs
Measured in 31 different transverse-mass (mT) bins
Charged pions → Coulomb interaction → (approx.) Coulomb correction
0-30% Centrality
Example corr. func.
1D projections
out side long
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Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
The results of this work
The size of the sourceLevy-scale parameter vs. mT describes the size of the sourceComparison with 1D Levy results
A. Adare et al. (PHENIX), Phys. Rev. C 97, 064911 arXiv:1709.05649
Source is not sphericalHydro scaling: R ∝ 1/
√mT
out side long
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Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
The results of this work
The strength of the correlation
]2 [GeV/cTm0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
λ
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
3D-π-π 3D+π+π 1D (arXiv:1709.05649)-π-π 1D (arXiv:1709.05649)+π+π
PHENIX 0-30% Centrality = 200 GeVNNsAu+Au
PH ENIXpreliminary
Correlation strength vs. mT
Ratio of resonance pions from Core-Halo model:√λ = NCore
NCore+NHalo
Agreement with previous 1D Levy results
Balint Kurgyis Eotvos University, Budapest
Three-dimensional Levy HBT 9 / 12
Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
The results of this work
The shape of the correlation
]2 [GeV/cTm0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
α
0.8
1
1.2
1.4
1.6
1.8
3D-π-π 3D+π+π 1D (arXiv:1709.05649)-π-π 1D (arXiv:1709.05649)+π+π
PHENIX 0-30% Centrality = 200 GeVNNsAu+Au
PH ENIXpreliminary
Levy exponent vs. mT describes the shape of correlation function
Far from Gaussian (α = 2) or Cauchy (α = 1)
Also far from 3D Ising value at CEP (α ≤ 0.5)
Agreement with previous 1D Levy results
Balint Kurgyis Eotvos University, Budapest
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Introduction Three-dimensional Levy analysis Levy HBT at the PHENIX experiment Summary
Status of Levy analyses
Open questions
Centrality and collision energy dependence? → PHENIX Preliminary
Do we see any non-monotonicity?
What is the reason for the appearing Levy distributin?
Checking different hadrons (kaons)Smaller tot. cross-section → heavier tail ?
Correlation strength only affected by Core-Halo effects?
Three particle correlations may show if coherence plays a role
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Summary
The results of this work:
Acceptable fits assuming Levy source in 3D
These results are consistent with the 1D Levy results
α Levy exponent: non-Gaussian, anomalous diffusion?
Scale parameter: hydro like scaling: R ∝ 1/√mT
The source is not spherical
]2 [GeV/cTm0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
λ
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
3D-π-π 3D+π+π 1D (arXiv:1709.05649)-π-π 1D (arXiv:1709.05649)+π+π
PHENIX 0-30% Centrality = 200 GeVNNsAu+Au
PH ENIXpreliminary
out side long
]2 [GeV/cTm0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
α
0.8
1
1.2
1.4
1.6
1.8
3D-π-π 3D+π+π 1D (arXiv:1709.05649)-π-π 1D (arXiv:1709.05649)+π+π
PHENIX 0-30% Centrality = 200 GeVNNsAu+Au
PH ENIXpreliminary
Thank you for your attention!