1. Collectivity in small systems measured with PHENIX at RHIC
Tamás Novák
Moriond QCD – March 29th 2019, La Thuile, Italy
Based on Sylvia Morrow’s talk at DNP-JSPS18, M. Csanád’s PHENIX talk at Zimányi 2018 and T. Csörgő’s talk at COST Workshop 2019

2. Outline RHIC d+Au Beam Energy Scan RHIC Geometry Scan
p/d/3He+Au: v2, v3
Hydrodynamic predictions
CGC postdictions
QGP droplets engineered
Summary
Tamás Novák

3. RHIC Beam Energy Scan
Is it due to the appearance of the sQGP (i.e. a strongly coupled fluid)?
If yes, how much time is needed
to spend in QGP phase?
Test: d+Au collisions from
20 to 200 GeV
Phys.Rev.Lett. 120 (2018) no.6,
Phys.Rev. C96 (2017) no.6,
Tamás Novák

4. Origin of Final State Collectivity
Is it due to initial geometry and hydro?
Hydrodynamics: initial spatial correlations
Alternative: initial momentum correlations
Test (Geometry scan): p+Au, d+Au, 3He+Au at √s =200 GeV
How do v2 and v3 evolve with initial state geometry?
RHIC operations: versatility.
Tamás Novák

5. Geometry Scan: 3 Different Shapes
Hydrodynamics (SONIC, LQCD EoS, 1+2d):
Different initial geometry /energy deposition translated by 𝛻p
to different final state momentum space correlations
Tamás Novák

6. PHENIX Detector System
CNT: Charged particle tracking, central arm
FVTX: Charged p. tracking, event plane; BBC: event plane, centrality
Tamás Novák

7. Geometry Scan: v2 results
Consistent with
hydro and geometry ordering
Tamás Novák

8. Geometry Scan: v3 results
Consistent with
hydro and geometry ordering
Tamás Novák

9. Flow in Small Systems: Geometric Ordering
v2, v3 results beautifully consistent with hydro ordering
What about quantitative test and/or alternative explanations?
Tamás Novák

10. Comparison to Hydro Calculations
Tamás Novák

11. Is there any altenative explanation?
Hydro: initial state spatial correlations a.k.a. geometry
Alternative: initial state momentum correlations Mace et al. Phys. Rev. Lett. 121, (2018)
Final state momentum correlations
Tamás Novák

12. Alternative Model vs Data
MSTV postdiction (Mace, Skokov, Tribedy, Venugopalan, PRL121, )
Reasonable v2 description, misses v3 ordering
Tamás Novák

13. Data vs Hydro vs MSTV Can we distinquish models „by eye” ?
Tools for discrimination: confidence levels
MSTV: multiplicity dependence; test v2 at same dN/dh
Tamás Novák

14. Statistical Test of Three Models
QGP droplet and hydro have good to excellent p-values for all 6 distributions;
MSTV marginal in d+Au, He+Au, excluded for p+Au and combined
Tamás Novák

15. MSTV Prediction Fails Qualitatively for v2 at Fixed Multiplicity
Compare similar collision systems
Tamás Novák

16. Summary Strong evidence for QGP droplets in small systems
Good confidence levels for hydro p/de/3He+Au
Partially supported by EFOP
and the NKTIH grants FK and FK
Tamás Novák

17. Thank you for your attention!
Questions?
Tamás Novák

18. The latest from MSTV: arXiv:1901.10506v1
30% uncertainties are added
• hard to evaluate the data to theory comparison without knowledge of the
correlations in these uncertainties
• in particular, it is very important to know how the uncertainties are correlated
between harmonics and systems
Tamás Novák

19. Nature Physics Editorial: QGP, drop by drop
Tamás Novák

20. MSTV2: central d+AU and 20-40% d+AU are nearly identical
Tamás Novák