Energy scan programs in HIC Anar Rustamov [email protected]¤ Onset of Deconfinement Signals ¤ Particle spectra ¤ Azimuthal modulations ¤ Event-by-Event Fluctuations ¤ Critical point ¤ Phase Boundaries ¤ Confronting measured signals with theory ¤ Conclusions
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Energy scan programs in HIC - University of Wrocławift.uni.wroc.pl/~cpod2016/Rustamov.pdf · Energy scan programs in HIC Anar Rustamov [email protected] ¤ Onset of Deconfinement
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Statistical approach works in the energy range spanning by 3 orders of magnitude!
suppression factor =
HADES data
arxiV: 1512.07070
I1 2z( )I0 2z( )
z – sum of single particle partition functions P. Braun-Munzinger, K. Redlich, J. Stachel In *Hwa, R.C. (ed.) et al.: Quark gluon plasma* 491-599 A.R, M. I. Gorenstein RLB731, 302 (2014)
THERMUS V3.0: S. Wheaton, J.Cleymans: Comput.Phys.Commun.180:84-106,2009
Results from STAR
A. Rustamov, CPOD 2016, Wroclaw, Poland
Non-monotonic behavior for third an fourth cumulants! In this connected to the critical point? Can these results be directly compared with HRG and or LQCD results? How to interpret consistencies and/or deviations?
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PRL 112 32302 (2014) + QM15
A. Rustamov, CPOD 2016, Wroclaw, Poland
Results from PHENIX/STAR
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PRC93 (2016) 011901(R)
Data matches with the difference of two Negative Binomial densities fitted to the single multiplicity distributions
PRL 112 32302 (2014) + QM15
Consistent with the Skellam Baseline Larger error bars for kσ 2
PHENIX STAR
No direct comparison due to different acceptances
Extraction of freeze-out parameters
A. Rustamov, CPOD 2016, Wroclaw, Poland
Different T/μ values from STAR and PHENIX? Need for more precise measurements. Is it justified to extract parameters in this way?
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Trivial volume fluctuations Conservation laws Measurements depend on acceptance!
PRC93 (2016) 011901(R)
A. Bazavov et al., Phys. Rev. Lett. 109 (2012) 192302.
J. Cleymans et al., PRC73 (2006) 034905.
M. J. Tannenbaum, arXiv:1604.08550v1
s1/2=27GeV
Trivial (volume) fluctuations
Model of independent particles sources
N = n1 + n2 + ...+ nNs= n Ns
N 2 = n2 Ns + n 2 Ns2 − Ns( )
n n n n
n1 n2 n3 … ns
A. Rustamov, CPOD 2016, Wroclaw, Poland 19
c2 N( ) = Ns c2 n( )+ n2c2 Ns( )
Volume fluctuation part vanishes for midrapidity net-particles at ALICE energies!
• The strategy: • Perform fluctuation analysis in larger acceptance (keep dynamical fluctuations) • Subtract contributions from conservation laws • Compare to baselines from LQCD and/or HRG model
B n;N ,α( ) = N!
n! N −n( )!αn 1−α( )N−n
α = n N
Recipe for net-proton analysis in ALICE
A. Rustamov, CPOD 2016, Wroclaw, Poland 21
c2 p− p( )Skellam
First experimental results from ALICE will be released soon!
Proposed comparison procedure:
• Perform analysis for
• Calculate acceptance factors based on experimental data
• Correct the experimental data
• Compare to LQCD
1
ΔηΔηth
Δη > Δηth
α Δη( ) = p
acc
B4π
1−αc2 p− p( )Skellam
=1−α
α =
npacc
NB4π
Conclusions
A. Rustamov, CPOD 2016, Wroclaw, Poland 22
• Around 30 GeV (s1/2 ≈ 7.6 GeV ) a wide variety of experimental measurements show non-monotonic energy dependences
• Some of these signals can be interpreted without explicit assumption of
phase transition • Nor clear signals for the critical point are observed so far
• Problems in understanding E-by-E measurements of conserved charges22 • How to put acceptance threshold? • How to correct for conservation laws and volume fluctuations?
• New results on net-proton, net-kaon and net-pion fluctuations from ALICE will be released soon