OBSERVABLE SIGNATURES OF INITIAL STATE MOMENTUM ANISOTROPIES IN NUCLEAR COLLISIONS CHUN SHEN RBRC RIKEN BNL Research Center ALICE Journal Club Dec. 8, 2020 Phys.Rev.Lett. 125 (2020) 19, 192301 arXiv: 2006.15721 [nucl-th]

Chun Shen (WSU/RBRC) ALICE Journal Club /33 2 Initial energy density Hadronization Kinetic freeze-out final detected particles distributions QGP phase e+ e- Hadron gas phase τ ~ 0 fm/c τ ~ 1 fm/c pre- equilibrium dynamics Relativistic Heavy-Ion Collisions free streaming τ ~ 10 fm/c viscous hydrodynamics collision evolution π K p τ ~ 1015 fm/c Complex dynamics driven by multiple length scales Hybrid multi-stage modeling with event-by-event fluctuations RELATIVISTIC HEAVY-ION COLLISIONS

Chun Shen (WSU/RBRC) ALICE Journal Club /33 DEFINING THE QUARK-GLUON PLASMA Which properties of hot QCD matter can we determine from relativistic heavy ion data (LHC, RHIC, and future FAIR/NICA/JPAC)? Equation of State DB, DQ, DS AAAB+nicdVDLSgMxFM3UV62vqS7dBIvgogwzVdTuSu3CZYv2Ae0wZNJMG5rJDElGKWM/xY0LRdz6Je78G9OH4PPA5R7OuZfcHD9mVCrbfjcyS8srq2vZ9dzG5tb2jpnfbckoEZg0ccQi0fGRJIxy0lRUMdKJBUGhz0jbH11M/fYNEZJG/FqNY+KGaMBpQDFSWvLMfM2rFntFWPMa83blmQXbKttO+dSBv4lj2TMUwAJ1z3zr9SOchIQrzJCUXceOlZsioShmZJLrJZLECI/QgHQ15Sgk0k1np0/goVb6MIiELq7gTP26kaJQynHo68kQqaH86U3Fv7xuooJzN6U8ThTheP5QkDCoIjjNAfapIFixsSYIC6pvhXiIBMJKp5XTIXz+FP5PWiXLObZKjZNCpbqIIwv2wQE4Ag44AxVwCeqgCTC4BffgETwZd8aD8Wy8zEczxmJnD3yD8foBUi+SHg== Charge diffusion Spectra, collective flow, femtoscopy, light-nuclei production, net-proton fluctuations Anisotropic flow vn Flow correlations Balance functions Initial Fluctuation spectrum & baryon stoping Tµ⌫(⌧, r), Jµ(⌧, r) AAACGHicdVDJSgNBEO2JW4xb1KOXxiBECHEmippb0It4ipANMkno6fQkTXp6hl6EMOQzvPgrXjwo4jU3/8bOImjUBwWP96qoqudFjEpl2x9WYml5ZXUtuZ7a2Nza3knv7tVkqAUmVRyyUDQ8JAmjnFQVVYw0IkFQ4DFS9wbXE79+T4SkIa+oYURaAepx6lOMlJE66ZNKO3YD7XI9yroK6RyMXc+HYnScg7dt4yyonXTGzhdtp3juwN/EydtTZMAc5U567HZDrAPCFWZIyqZjR6oVI6EoZmSUcrUkEcID1CNNQzkKiGzF08dG8MgoXeiHwhRXcKp+n4hRIOUw8ExngFRfLnoT8S+vqZV/2Yopj7QiHM8W+ZpBFcJJSrBLBcGKDQ1BWFBzK8R9JBBWJsuUCeHrU/g/qRXyzmm+cHeWKV3N40iCA3AIssABF6AEbkAZVAEGD+AJvIBX69F6tt6s91lrwprP7IMfsMaf5XCfDg== Net particle distributions Critical point & 1st order PT Shear and bulk viscosities (η/s)(T, {μq }), (ζ/s)(T, {μq }) e(T, {μq }), P(T, {μq }), c2 s (T, {μq }) 3

Chun Shen (WSU/RBRC) ALICE Journal Club /33 4 A long wavelength effective description of interacting systems Conservation laws + Equation of State Star formation Quark-Gluon Plasma Air dynamics of race car Studying collective phenomena in heavy-ion collisions has been leading the theory frontier of developing causal viscous relativistic hydrodynamics COLLECTIVITY & HYDRODYNAMICS

Chun Shen (WSU/RBRC) ALICE Journal Club /33 5 Shear viscosity ⇡µ⌫ ⇠ 2⌘rhµu⌫i Resistance to deformation STUDY QGP TRANSPORT PROPERTIES no shear viscosity with shear viscosity Shear viscosity smears out the fine flow patterns Flow anisotropy is imprinted to final state particle momenta K O

Chun Shen (WSU/RBRC) ALICE Journal Club /33 6 Shear viscosity ⇡µ⌫ ⇠ 2⌘rhµu⌫i Resistance to deformation STUDY QGP TRANSPORT PROPERTIES no shear viscosity with shear viscosity Shear viscosity smears out the fine flow patterns Flow anisotropy is imprinted to final state particle momenta

Chun Shen (WSU/RBRC) ALICE Journal Club /33 7 EFFECTS OF BULK VISCOSITY no bulk viscosity with bulk viscosity Bulk viscosity ⇧ ⇠ ⇣@µuµ Resistance to expansion • Bulk viscosity slows down radial expansion and produces more entropy

Chun Shen (WSU/RBRC) ALICE Journal Club /33 8 EFFECTS OF BULK VISCOSITY no bulk viscosity with bulk viscosity Bulk viscosity ⇧ ⇠ ⇣@µuµ Resistance to expansion • Bulk viscosity slows down radial expansion and produces more entropy

Chun Shen (WSU/RBRC) ALICE Journal Club /33 9 CMS event display v1 v2 v3 v4 v5 dN d = N 2⇡ (1 + 2 1 X n=1 vn cos( n)) 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 ANISOTROPIC FLOW

Chun Shen (WSU/RBRC) ALICE Journal Club /33 10 n 2 3 4 5 6 7 | > 2} η Δ {2part, | n v 0.00 0.01 0.02 0.03 0.04 = 2.76 TeV NN s CMS PbPb -1 b µ = 120 int L < 3.0 GeV/c T 0.3 < p 2.5-5.0%, HF 0-2.5%, HF 0-1%, HF+NPixel 0-0.2%, HF+NPixel 0-0.02%, HF+NPixel Plank 2013 Inflation E V E N T- B Y- E V E N T F L U I D • Evolve many initial shapes using vi • Convert energy density to particles • Determine coefficients of particl • Average and compare to experime 9 ! C . G A L E , S . J E O N , B . S C H E N K E , P. T R I B E D Y, R . V E N U G O PA L A N , ۘ Hydrodynamics v1 v2 v3 v4 v5 FLUCTUATION POWER SPECTRUM Planck Collaboration: The Planck mission 2 10 50 0 1000 2000 3000 4000 5000 6000 D [µK2] 90 18 500 1000 1500 2000 2500 Multipole moment, 1 0.2 0.1 0.07 Angular scale Fig. 19. The temperature angular power spectrum of the primary CMB from Planck, showing a precise measurement of seven acoustic peaks, that are well fit by a simple six-parameter ⇤CDM theoretical model (the model plotted is the one labelled [Planck+WP+highL] in Planck Collaboration XVI (2013)). The shaded area around the best-fit curve represents cosmic variance, including the sky cut used. The error bars on individual points also include cosmic variance. The horizontal axis is logarithmic up to ` = 50, and linear beyond. The vertical scale is `(` + 1)Cl /2⇡. The measured spectrum shown here is exactly the same as the one shown in Fig. 1 of Planck Collaboration XVI (2013), but it has been rebinned to show better the low-` region.

Chun Shen (WSU/RBRC) ALICE Journal Club /33 11 HYDRODYNAMIC RESPONSES TO GEOMETRY • Elliptic flow shows good linear response to initial eccentricity • The slope encodes the hydrodynamic response

Chun Shen (WSU/RBRC) ALICE Journal Club /33 12 RUNNING THE GAMUT OF HIGH ENERGY NUCLEAR COLLISIONS • One single set of model parameters for ALL types of collisions at the top RHIC and LHC energies RHIC LHC B. Schenke, C. Shen and P. Tribedy, Phys. Rev. C 102, 044905 (2020)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 13 M. Strickland, Nucl. Phys. A982, 92-98 (2019) HOW TO QUANTIFY INITIAL STATE CORRELATIONS

Chun Shen (WSU/RBRC) ALICE Journal Club /33 14 THE HYBRID THEORETICAL FRAMEWORK τ (fm) 0+ AAAB6nicbVDLSsNAFJ3UV62vqks3g0UQhJA02tpd0Y3LivYBbSyT6aQdOpmEmYlQQj/BjQtF3PpF7vwbJ2kQXwcuHM65l3vv8SJGpbKsD6OwtLyyulZcL21sbm3vlHf3OjKMBSZtHLJQ9DwkCaOctBVVjPQiQVDgMdL1ppep370nQtKQ36pZRNwAjTn1KUZKSzfW3cmwXLHMhlO3G3WYkapTy4l9Bm3TylABOVrD8vtgFOI4IFxhhqTs21ak3AQJRTEj89IgliRCeIrGpK8pRwGRbpKdOodHWhlBPxS6uIKZ+n0iQYGUs8DTnQFSE/nbS8X/vH6s/HM3oTyKFeF4sciPGVQhTP+GIyoIVmymCcKC6lshniCBsNLplBYhpKh9vfyXdKqm7ZjO9WmleZHHUQQH4BAcAxvUQRNcgRZoAwzG4AE8gWeDGY/Gi/G6aC0Y+cw++AHj7RMzLY3l 0.4 AAAB6nicbVDLSsNAFJ3UV62vqks3g0VwFSZtiborunFZ0T6gDWUynbRDJ5MwMxFK6Ce4caGIW7/InX/jpAni68CFwzn3cu89fsyZ0gh9WKWV1bX1jfJmZWt7Z3evun/QVVEiCe2QiEey72NFORO0o5nmtB9LikOf054/u8r83j2VikXiTs9j6oV4IljACNZGukV2c1StIfvCRQ6qw5y4bkEaDejYaIkaKNAeVd+H44gkIRWacKzUwEGx9lIsNSOcLirDRNEYkxme0IGhAodUeeny1AU8McoYBpE0JTRcqt8nUhwqNQ990xliPVW/vUz8zxskOjj3UibiRFNB8kVBwqGOYPY3HDNJieZzQzCRzNwKyRRLTLRJp5KHkMH9evkv6dZtp2E3bpq11mURRxkcgWNwChxwBlrgGrRBBxAwAQ/gCTxb3Hq0XqzXvLVkFTOH4Aest0/TSo2l IP-Glasma Hydrodynamics (MUSIC) Transport (UrQMD) Tμν • The Color Glass Condensate predicts anisotropic particle productions because of 1. Local anisotropies in the color fields 2. Local density gradients 3. Quantum interference effects ℰp = εp ei2ψp 2 = ⟨Txx − Tyy⟩ + i⟨2Txy⟩ ⟨Txx + Tyy⟩ • Continuously connect between different stages Tμν ~ B. Schenke, C. Shen and P. Tribedy, Phys. Rev. C 102, 044905 (2020)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 15 Correlation gradually vanishes !41 the more peripheral we go B. Schenke, C. Shen, P. Tribedy, in preparation B j ö r n S c h e n k e , B N L GEOMETRY CORRELATION GRADUALLY VANISHES • The correlation between triangular flow and spatial triangularity decreases in peripheral collisions • Other components of energy- momentum tensor in initial state become important B. Schenke, C. Shen and P. Tribedy, Phys. Rev. C 102, 044905 (2020)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 16 • The elliptic flow in small system shows strong correlation with system’s initial momentum anisotropy GEOMETRY CORRELATION GRADUALLY VANISHES ℰ2 = ε2 ei2ψ2 = ⟨x2 − y2⟩ + i⟨2xy⟩ ⟨x2 + y2⟩ ℰp = εp ei2ψp 2 = ⟨Txx − Tyy⟩ + i⟨2Txy⟩ ⟨Txx + Tyy⟩ B. Schenke, C. Shen and P. Tribedy, Phys. Lett. B803, 135322 (2020) Geometric ellipticity Momentum anisotropy

Chun Shen (WSU/RBRC) ALICE Journal Club /33 17 Qε = Re{⟨ℰV* 2 ⟩} ⟨|ℰ|2 ⟩⟨|V2 |2 ⟩ INITIAL STATE ANISOTROPIES VS HYDRODYNAMIC RESPONSE B. Schenke, C. Shen and P. Tribedy, Phys. Lett. B803, 135322 (2020) Examine the Pearson correlation between initial state and final state in the model ℰ2 , ℰp V2 The elliptic flow in low multiplicity events is more strongly correlated with than ℰp ℰ2

Chun Shen (WSU/RBRC) ALICE Journal Club /33 18 IS THERE AN OBSERVABLE? that can distinguish initial state momentum anisotropies from the final state effects on a qualitative level

Chun Shen (WSU/RBRC) ALICE Journal Club /33 19 CORRELATION BETWEEN V2 AND MEAN PT AT FIXED MULTIPLICITY ̂ ρ2 (v2 2 , ⟨pT ⟩) = ⟨ ̂ δv2 2 ̂ δ⟨pT ⟩⟩ ⟨( ̂ δv2 2 )2⟩⟨( ̂ δ⟨pT ⟩)2⟩ P. Bozek, Phys. Rev. C 93, 044908 (2016) Fluctuations from multiplicity(centrality) can be removed by binning events into unit multiplicity bins or by the following procedure ̂ δO ≡ δO − δOδN σ2 N δN δO ≡ O − ⟨O⟩ B. Schenke, C. Shen, and D. Teaney, Phys.Rev.C 102, 034905 (2020) Event-by-event correlation between and At fixed multiplicity: reduce contamination from system size fluctuations v2 ⟨pT ⟩ remove the linear correlation between the observable and multiplicity O A. Olszewski and W. Broniowski, Phys. Rev. C 96, 054903 (2017)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 20 WHAT EVENTS DOES SELECT? ⟨pT ⟩ ⟨pT ⟩ > ⟨⟨pT ⟩⟩ ⟨pT ⟩ < ⟨⟨pT ⟩⟩ Smaller system, higher density gradients, hotter Larger system, lower density gradients, colder Gardim, Giacalone, Luzum, Ollitrault, 1908.09728 B. Schenke, C. Shen, and D. Teaney, Phys.Rev.C 102, 034905 (2020) Qξ = ̂ δPT ̂ δξ ⟨( ̂ δPT )2⟩⟨( ̂ δξ)2⟩ PT = N⟨pT ⟩ The system’s is strongly anti- correlated with the transverse area ⟨pT ⟩

Chun Shen (WSU/RBRC) ALICE Journal Club /33 21 HOW DOES V2 CORRELATE WITH EVENT SHAPE IN SMALL SYSTEMS? Geometric Response: ε2 (A) > ε2 (B) v2 (A) > v2 (B) R(A) > R(B) ⟨pT ⟩(A) < ⟨pT ⟩(B) and are anti-correlated v2 ⟨pT ⟩ G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 22 HOW DOES V2 CORRELATE WITH EVENT SIZE IN SMALL SYSTEMS? Color Glass Condensate: εp (A) < εp (B) v2 (A) < v2 (B) R(A) > R(B) ⟨pT ⟩(A) > ⟨pT ⟩(B) and are correlated v2 ⟨pT ⟩ G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 23 THE FULL PICTURE — WHICH ONE DOMINATES? 0 5 10 15 20 dNch /d¥ °0.4 °0.3 °0.2 °0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 ˆ Ω d+Au 200 GeV 0.2 < pT < 2 GeV IP-Glasma+MUSIC+UrQMD ˆ Ωest (≤2 2 , [s]): Predictor: Initial geometry ˆ Ωest (≤2 p , [s]): Predictor: Initial momentum anisotropy G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) For , initial state correlation dominates dNch/dη ≲ 10 We predict a sign change of the correlator with multiplicity in p/d+Au collisions at RHIC and p+Pb collisions at LHC ̂ ρ2 For , final state response to geometry dominates dNch/dη ≳ 10 The full correlation smoothly move from one initial- state predictor to the other ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 24 THE FULL PICTURE — WHICH ONE DOMINATES? G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) Setting the initial momentum anisotropy to zero, our results follow the geometric predictor for all as expected (no sign change) dNch/dη ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 25 G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) B. Schenke, C. Shen, and D. Teaney, Phys.Rev.C 102, 034905 (2020) P+PB COLLISIONS AT THE LHC Current LHC measurements is consistent with our model in the final state dominant region ̂ ρ2 (v2 2 , ⟨pT ⟩) ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 26 G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) B. Schenke, C. Shen, and D. Teaney, Phys.Rev.C 102, 034905 (2020) P+PB COLLISIONS AT THE LHC ? A gold mine to discover! ̂ ρ2 (v2 2 , ⟨pT ⟩) ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 27 B. Schenke, C. Shen, and D. Teaney, Phys.Rev.C 102, 034905 (2020) THE IN HEAVY-ION COLLISIONS ̂ ρ2 The measured in Pb+Pb collisions is dominated by final-state effects and is consistent with our model calculations ̂ ρ2 ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 28 0 20 40 60 80 100 centrality[%] °0.2 °0.1 0.0 0.1 0.2 0.3 0.4 ˆ Ω(v2 2 , [pT ]) 0.2 < pT < 2 GeV Xe+Xe 5440 GeV Pb+Pb 5020 GeV G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) PUSHING HEAVY-ION COLLISIONS TO THE EXTREME Pushing beyond 90% centrality at LHC also can reveal the initial state momentum anisotropy! ̂ ρ2 Our model predicts the sign of changes twice in Pb+Pb and Xe+Xe collisions at the LHC ̂ ρ2 Final state effects are strong in heavy-ion collisions at the LHC up to 80% in centrality ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 29 0 20 40 60 80 100 centrality[%] °0.2 °0.1 0.0 0.1 0.2 0.3 0.4 ˆ Ω(v2 2 , [pT ]) 0.2 < pT < 2 GeV Xe+Xe 5440 GeV Pb+Pb 5020 GeV G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) PUSHING HEAVY-ION COLLISIONS TO THE EXTREME Pushing beyond 90% centrality at LHC also can reveal the initial state momentum anisotropy! ̂ ρ2 Final state effects are strong in heavy-ion collisions at the LHC up to 80% in centrality final state response Initial state anisotropy Our model predicts the sign of changes twice in Pb+Pb and Xe+Xe collisions at the LHC ̂ ρ2 ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 30 OPPORTUNITIES IN O+O COLLISIONS G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) Smaller O+O collisions at LHC have sign changes in semi-peripheral centrality ̂ ρ2 (v2 2 , ⟨pT ⟩) ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 31 COLLISION ENERGY DEPENDENCE G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) More systematic comparisons can be made if O+O collisions are measured at both RHIC and LHC ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 32 COLLISION ENERGY DEPENDENCE G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) Our model predicts qualitatively different behaviors between RHIC and LHC because of shorter fireball lifetime at RHIC No sign change in in Au+Au collisions at RHIC because of weaker final state responses ̂ ρ2 Two sign changes in in Pb+Pb collisions at LHC ̂ ρ2 ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 33 EXCITING PRELIMINARY RESULTS AT RHIC Our model prediction shows promising agreement with the preliminary STAR data Chunjian Zhang, APS DNP meeting 2020 G. Giacalone, B. Schenke and C. Shen, Phys. Rev. Lett. 125, 192301 (2020) 100 101 102 103 dNch /d¥ °0.4 °0.2 0.0 0.2 0.4 0.6 ˆ Ω(v2 2 , [pT ]) 0.2 < pT < 2 GeV Au+Au 200 GeV Au+Au 200 GeV, final state only ̂ ρ2 (v2 2 , ⟨pT ⟩)

Chun Shen (WSU/RBRC) ALICE Journal Club /33 34 AN OPEN SOURCE HYBRID FRAMEWORK—IEBE-MUSIC Spectra & flow analysis UrQMD SMASH MUSIC + Lattice EoS Electromagnetic fields Spectators Dynamical initialization + 3D-MCGlauber model Particlization iSS Experimental measurements The iEBE-MUSIC Framework KoMPoST IPGlasma The state-of-the-art event-by-event simulations for relativistic heavy-ion collisions https://github.com/chunshen1987/iEBE-MUSIC

Chun Shen (WSU/RBRC) ALICE Journal Club /33 35 SUMMARY • The correlation between and is qualitatively different from the CGC and hydrodynamic responses ̂ ρ2 v2 ⟨pT ⟩ • Anisotropic flow coefficients in events with can reveal the primordial momentum anisotropy of collisions dNch/dη ≲ 10 • With the IPGlasma+MUSIC+UrQMD hybrid framework, we predict the changes sign once in small systems ̂ ρ2 the changes sign twice in large systems at LHC ̂ ρ2 the has no sign change in large systems at RHIC ̂ ρ2 • Experimental observations of these features would be the important indication of initial state momentum anisotropies from the CGC

Chun Shen (WSU/RBRC) ALICE Journal Club /33 36

Chun Shen (WSU/RBRC) ALICE Journal Club /33 37 0.00 0.05 0.10 0.15 ¥/s 0.0 0.5 1.0 1.5 øº (fm) tune causality bound 0.1 0.2 0.3 0.4 T (GeV) 0.00 0.05 0.10 0.15 ≥/s 0.1 0.2 0.3 0.4 T (GeV) 0.00 0.25 0.50 0.75 ø¶ (fm) TRANSPORT COEFFICIENTS B. Schenke, C. Shen and P. Tribedy, Phys. Rev. C 102, 044905