Anastasios Taliotis: Un. Of Crete, CCTP Elias Kiritsis and Anastasios Taliotis Arxiv:[ ]

Outline Goals: State Problem/Facts from HIC Tools: Relating AdS/CFT with Multiplicities Introduction to TS, an example Review of earlier works Possible improvement ingredients: IR applied to several geometries Digression: pQCD and the Saturation Scale Qs and weak coupling matching Quantized, Normalizable Modes Results, Data and Predictions Conclusions/Future Work 1

Goals: State Problem/Data 2

Goal I. Finish on Time 3

Goal II.: State Problem/Data Heavy Ion Collisions: isentropic evolution from Yellow  Blue [AdS approach:Kiritsis,Taliotis] Stages of Collision initial state pre-equilibrium QGP and hydrodynamic expansion hadronization hadronic phase and freeze-out 4

Multiplicities N ch initial state pre-equilibrium QGP and hydrodynamic expansion hadronization hadronic phase and freeze-out 5

N ch from Confining and non-confining matter Find I. Conformal matter (AdS 5 ): II. Confined matter: 6

Relating S with N ch 1 Charged part. ÷ ½ Neutral part. => N tot = N ch + N neu = 3/2N ch units of S [Heinz] => S prod =5 × 3/2 × N ch =7.5N ch Use N ch, N tot, S prod interchangeably (proportional) 7 N ch = S prod /7.5

Tools: Relating AdS/CFT with N ch 8

AdS/CFT Basic Result AdS/CFT: S ST = S GT Conclude: Estimating S prod ST  N ch Estimate S prod using standard thms of GR [Penrose, Hawking, Ellis] 9

Introduction to TS 10

What this method does not: [Ads:,Albacete,Kovcegov,Taliotis;Romatscke, Chesler,Yaffe,Heller,Janik,Peschanski…, Flat:D’Eath,Payne,Konstantinu,Tomaras,Spirin,Taliotis…] What this method can do: S trap ≤S prod. By reducing to unusual BV problem [Giddings,Eardly,Nastase,Kung,Gubser,Yarom,Pufu,Kovchegov, Shuryak,Lin,kiritsis,Taliotis,Aref’eva,Bagrov,Joukovskaya,...] [Picture from GYP] marginally trapped surface 11

Example: 4D Flat Superimpose two A/S solutions Head On & 12

[Giddings & Eardley,03’] 13

Review Earlier Works 14

AdS Dictionary: BC of TS imply. Note presence Then Shock Metric in AdS 15 [Gubser,Yarom,Pufu,Tanaka,Hotta] [Gubser,Yarom,Pufu]

To check data must choose  Lattice [GYP] N ch ~ s 1/3 [GYP,08’] Data N ch ~ s 1/4. Indeed: Lessons: (i) A brave effort absorb QFT complexities in a BV problem (ii) Worth further investigation Q: What is missing? Plot:[GYP,08’] 16 PHOBOS, Arxiv:

Possible Improvement Ingredients 17

IR physics: Confinement According data large fraction of particles produced low p T ~2-300 MeV~Λ QCD. [CMS Col.] Suggests possibility non-pQCD effects be important Conclude: confinement may improve AdS/CFT results 18

IHQCD Dilaton-Gravity Theories [Gursoy,Kiritsis,Nitti,Mazzanti,Michalogiorgakis,Gubser,Nelore] Appropriate scalar V’s and using results Where scale factors b(r) can be (i)Non-confining: (ii)Confining: 19

Entropy from Uniform and Non- Uniform transverse profiles with or without confinement 20

Uniform Transverse Glueballs Using BC & TS volume Cases Analyzed: I. Non-Confining II. Confining III. Confining IV. Confining 21

Non-Uniform Transverse Glueballs Cases Analyzed: I. Power-Like II. Exponential (Numerically) 22 Confining Non-Confining ☐ϕ =δ(x-x’)

Most S produced from UV Observation: According to AdS/CFT for classes of b(r)’s most S produced in UV part of the TS Argument: Have shown => as E  large, then r UV  0 Have But integrand singular at UV => most S comes from UV E 1 E2E2 E3E3 r’ r UV r IR 23

At UV g expect N ch ~small=> S ~small. Maybe we should not used geometry where it breaks down Way out? Incorporate weak coupling physics.. How? Cut surface at r c1 (E)>r UV (E) for all E [GYP] But where exactly? 24

Digression: pQCD and Qs 25

Intuitive def: Qs is a trans. scale in nucleus color charge becomes dense Free=interaction: Strong classical gluon field  g >Λ QCD A μ strong, then CGC theory applies and Q s pertubatively; details: [Dumitru,Jalalian-Marian,Kovchegov,,BNL group: McLerran,Venugopalan,Khrazeev,…] 26 Saturation Scale

Cutting the TS Propose cut TS at r s ~1/Q s provided r s >r UV Effectively treat weak-strong coupling matching by step-function (see results follow) 27

Localized Transverse Distributions & Quantized, Normalizable Modes 28

An Interesting Geometry: normalized Quantized Gravitons: Then  finite pnomials Normalizable: [Kiritsis, Mazzanti,Michalogiorgakis,Nitti] Linear glueball trajectories: [Kiritsis, Mazzanti,Nitti] 29

TS for the n=1 mode Generally Can show only C k 1 contributes: BC : (see results) 30

n th mode S trap Formulas adequate for numerical analysis 31

Recap N ch = S prod /7.5 Several b’s* (conf. or not)=> several S trap (s) None described data N ch ~s 1/4 or similar Most S comes from UV Cut TS at UV (i) E independent (ii) E depended Q s Seen quantized, normalizable, graviton (sm)wave-functions. T ++ falls-off exponentially (K o ) 32 *It is remarked that out of these geometries only AdS 5 reduces (trivially) to AdS 5 at the UV.

Results, Data & Predictions 33

Results.I We have constracted exact (point-like J ++ ) shocks. Exponential b’s with UV const cut yield S trap ~ log 2 (s). When b=(r/L) a=1 (confining) with UV const cut yields S trap ~ s 1/4 : fits data. AdS geometry with unif. profiles produces least S trap In confining geometries only normalizable modes result a TS Motivate a set of non trivial entropy inequalities, Define: a)GYP when b=L/r. T++ falls as power:~ 1/(x 2 +x 2 0 ) 3 b)IHQCD when b=L/r exp[-r 2 /R 2 ]. Neither has UV-cut. Then *: 34 *It is remarked that both of these geometries reduce (non-trivially generally) to AdS 5 at the UV.

Results.II: Non trivial inequalities Numerically or Analytically found: I. II. III. > > > > > 35 >

Results III. Attempt to Describe Data- Predictions (2 Geometries) 36

Predictions PbPb (A=207): N ch ≈19100, 27000, for 2.76, 5.5 and 7 TeV respectively. Geometry I. b=L/rexp[-r 2 /R 2 ] no UV cut-off;n=1 PHOBOS, Arxiv: AuAu PbPb

Predictions pp (A=1): N ch ≈70, 110, 190, 260, for 0.9, 2.36, 7 and 14 TeV respectively. Predictions PbPb (A=207): N ch ≈18750, , for 2.76, 5.5 and 7 TeV respectively. Geometry II. b=L/r with UV cut at c/Q s PHOBOS, Arxiv: Lattice;[GYP] 38 AuAu PbPb

Alice Preliminary Results: 2.76 TeV As collision gets more central (our case), data follow our curve better. In particular: at A=190, we predict N ch =17300!!! ALICE, Arxiv: Dashed line: Our theoretical curve as function of A at fixed s 1/2 =2.76 TeV. Data Points: N ch (N part/ /2). 39

Results III. Conclusions Both treatments seem to describe data. A more refined investigation required:  More careful matching with gravity parameters  More Data 40

Future Work…. 41

42 Thank you