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PHENIX Results from the RHIC Beam Energy Scan Brett Fadem for the PHENIX Collaboration Winter Workshop on Nuclear Dynamics 2016.

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Presentation on theme: "PHENIX Results from the RHIC Beam Energy Scan Brett Fadem for the PHENIX Collaboration Winter Workshop on Nuclear Dynamics 2016."— Presentation transcript:

1 PHENIX Results from the RHIC Beam Energy Scan Brett Fadem for the PHENIX Collaboration Winter Workshop on Nuclear Dynamics 2016

2 Topics With regard to the Beam Energy Scan: – Transverse Energy and Charged Particle Multiplicity – Combinations of Higher Order Cumulants of Net Charge – Combinations of HBT Radii 2

3 Mapping the QCD Phase Diagram 3 Models suggest: At high T and low μ B, transition is a smooth crossover At low T and high μ B, transition is first order

4 Transverse energy production and charged particle multiplicity √S NN Au + Au Cu + Cu Cu + Au D + Au 3 He + Au 200 ✔✔✔✔✔ 130 ✔ 62.4 ✔✔ 39 ✔ 27 ✔ 19.6 ✔ 14.5 ✔ 7.7 ✔ Physical Review C 93, 024901 2016 4

5 Transverse energy per participant is not constant vs. centrality 5

6 Transverse energy per quark participant IS constant vs. centrality 6

7 Excitation Functions – No non- monotonic behavior observed 7

8 There is a change in the transverse energy per charged particle at LHC energies relative to RHIC Plateau 8 Transverse energy from CMS, and N ch from ALICE

9 Second Topic: 9 Phys. Rev. C 93, 011901 (R) (2016) Measurement of higher cumulants of net-charge multiplicity distributions in Au+Au collisions at √S NN = 7.7-200 GeV

10 Correlation Length Motivated examination of Event-by-event fluctuations of various conserved quantities, such as: Net baryon # Net charge Net strangeness at critical end-point (CEP) in the thermodynamic limit Motivation 10

11 Using Lattice QCD Next to leading order Taylor series expansion around vanishing chemical potentials Cumulants of charge fluctuations are sensitive indicators of a transition from the hadronic to the QGP phase 11

12 Variances: Net-baryon # Net-charge Net-strangeness Where N is the multiplicity, and is the mean of the distribution 12

13 Higher cumulants are even more sensitive to the proximity of the CEP Skewness Kurtosis 13

14 Lattice QCD + Hadron Resonance Gas Model Cumulant ratios are independent of volume but are sensitive to kinematic acceptance [Phys.Lett. B726 (2013) 691-696] 14 Should show non- monotonic behavior when approaching the critical end point

15 Uncorrected Net Charge Distributions √S NN (GeV)7.719.6273962.4200 Analyzed Events2M6M21M154M474M1681M 15

16 Efficiency corrected cumulants 16

17 Dependence of Corrected Cumulant Ratios on Number of Participants 17 Weak dependence on number of participants

18 Higher moments in net-charge Multiplicity Distributions vs. √S NN No non- monotonic behavior observed 18 ( Green triangles are from cumulant theorem for difference of two Negative Binomial Distributions) Consistent with earlier STAR result [Phys. Rev. Lett., 113, 093201 (2014)] but PHENIX points have smaller statistical error.

19 Extraction of Freezeout Temperature and Baryon Chemical Potential from PHENIX Cumulants + Lattice 19 √S NN T f (MeV)μ B (MeV)T f (MeV)μ B (MeV) 27166±6181±21160±6184±21136±13.8 39158±5114±13156±5118±10101±10 62.4163±571±8159±574±866.6±7.9 200163±827±5159±825±722.8±2.6 PHENIX + A.Bazavov et al, and S. Mukherjee PhysRevLett 109,192302 (2012) PHENIX + S. Borsanyi et al Phys. Rev. Lett. 113, 052301 (2014) STAR + S. Borsanyi et al Phys. Rev. Lett. 111, 062005 (2013)

20 Baryon chemical potentials match thermal statistical model using identified particle yields 20 Thermal Statistical Model from J. Cleymans, Phys. Rev. C 73, 034905 (2006)

21 Topic 3 21 HBT – Beam-energy and system-size dependence of the space-time extent of the pion emission source produced in heavy ion collisions. arXiv:1410.2559

22 Define a new parameter to characterize the collision system 22 Note that, for central collisions, the initial Gaussian radius for the collision system Here, of the participants (in the x-y plane) in the collision derived from a MC-Glauber simulation. are the RMS widths

23 HBT Correlation Functions 23 Pair-coordinate system (Bertsch NPA498, Pratt PRD33) Correlation function: q long is along beam q out is along k T (average P T direction) q side is perpendicular to other two Coulomb corrected, and in LCMS frame:

24 Correlation Functions 24 Slices of the 3D two-pion (π + π + and π - π - ) correlation fcns.

25 Combos of HBT Radii 25 Non-monotonic behavior IS observed! arXiv:1410.2559 Sensitive to emission duration R long related to medium lifetime

26 Summary – Topic 1 Transverse Energy and Charge Multiplicities – E T per constituent quark participant is constant for all centralities, but E T per nucleon participant is not – The constituent quark model can account for all E T with no need to resort to a two part N part and N coll model – LHC E T per charged particle rises above the RHIC plateau 26

27 Summary – Topic 2 Measurement of higher cumulants of net- charge – No non-monotonic behavior observed in the net- charge cumulant combinations – Data are consistent with STAR Phys. Rev. Lett. 113, 029301, albeit with smaller error bars – Lattice QCD has been combined with PHENIX cumulants to produce freezeout temperature and baryon chemical potential that matches a thermal statistical model with identified particle. 27

28 Summary – Topic 3 Non-monotonic behavior is seen when plotting the above HBT quantities vs. √S NN 28 and

29 Backup 29

30 30 Slide from Mike Tannenbaum:

31 31


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