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

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

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

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,

Transverse energy per participant is not constant vs. centrality 5

Transverse energy per quark participant IS constant vs. centrality 6

Excitation Functions – No non- monotonic behavior observed 7

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

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

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

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

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

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

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

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

Efficiency corrected cumulants 16

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

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, (2014)] but PHENIX points have smaller statistical error.

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± ±5114±13156±5118±10101± ±571±8159±574±866.6± ±827±5159±825±722.8±2.6 PHENIX + A.Bazavov et al, and S. Mukherjee PhysRevLett 109, (2012) PHENIX + S. Borsanyi et al Phys. Rev. Lett. 113, (2014) STAR + S. Borsanyi et al Phys. Rev. Lett. 111, (2013)

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

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:

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

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:

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

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

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

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, , 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

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

Backup 29

30 Slide from Mike Tannenbaum:

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