# Presentation: 729040

## Understanding Quarkonia above Deconfinement 

- Ágnes Mócsy

## conclusion as outline

- potential models can reproduce some qualitative features of the heavy quarkonia lattice spectral functions
- survival of 1S state and melting of 1P state
- but the temperature-dependence of the **correlators** and quarkonia **properties** is not reproduced
- true for all temperature-dependent screened potentials
- screening is not responsible for quarkonia suppression
-  tscreening>tQQ

## why heavy QQ is interesting

***J/********* suppression** “unambiguous” signal of deconfinement
- Matsui, Satz 1986
- in QGP color Coulomb force between Q and Q gets screened by q and q
- Rscreening < RQQ  dissociation of quarkonium at Tc
-  sequential suppression
- modification of quarkonia properties could tell us about deconfinement

## how we study QQ

## from

- correlation functions of hadronic currents reliably calculated
-                                                               spectral function (,T)

- Umeda
- Hatsuda,Asakawa
- Datta et al 04
- Petreczky et al 06

- 1P charmonium is gone at 1.16Tc

- Petreczky et al 06

- M E M

- c0

## from 

-               1S charmonium survives up to 1.5Tc
-             correlator  spectral function does not change
-             spectral function  properties do not change

- contradiction with early potential model predictions

- Datta et al 04

- At what temperature do heavy quark bound states disappear?
- Can modification of quarkonia properties be understood via a temperature-dependent screened potential?
- If yes, what is the potential?
- If not, what is the mechanism behind quarkonia melting?

## potential MODEL

- assumption: Q-Q interactions are mediated by a potential
-                                                                   **we don’t know**
-                           assume a temperature-dependent potential V(r,T)
-             & solve Schrödinger’s equation to obtain properties of QQ

- confined

- deconfined

- J/

- r

- V(r)

- T = 0

- T > Tc

## screened potentials

- screened Cornell potential:
- fitted lattice internal energy:
- Wong potential:
-    mixture of lattice internal & free energy

- E.Shuryak,I.Zahed, 044

- C.Y.Wong 05

- Karsch,Mehr,Satz, 88

**Notes:**
put these into schr eq -- reproduce the fact that 1S does not disappear
all have t-dep screening

##             bound states/resonances    +    continuum

Mi(T) bound state mass
Fi(T) amplitude
S0(T) threshold

- Mi(T) bound state mass
- Fi(T) amplitude
- S0(T) threshold

- model spectral function

- 

- +

- =

- AM, P.Petreczky, EuroPhysJC (05)
-                             PRD 73 (06)
-                             hep-ph/0606053

## c0 correlator

- the c0 is gone just above Tc
- in agreement with lattice

## c correlator

- c correlator does not agree with lattice
- increase due to continuum, decrease due to amplitude reduction
- change in the spectral function disagrees with lattice
**feature for all screened potentials**

## non-relativistic Green’s function

- lattice internal energy                                                 Wong potential

**potential models still fail**
-  drastic change of mass & amplitude of 1S state
-  inconsistent with lattice
-  even though 1S survives in some screened potentials the spectral function is strongly modified

- AM,Petreczky, hep-ph/0606053
- AM,Petreczky,Casalderrey-Solana, in prep

- S-wave

## instead consider a toy model

**no temperature-dependent screening**
- no modification of the 1S properties - use PDG
- melting of 2S and 3S states
- melting of the 1P state
- continuum threshold s0 reduction

- 

- 1S

- 2S

- 3S

- T = 0

- T Tc

- 

- 1P

- AM, hep-ph/0606124

- s0

- s0

## the toy model

- c

- c0

- choice of s0 can keep correlators **as seen on the lattice**: c unchanged & c0 increased
**compensate for the melting of higher excited states above T****c**** **
**with the decrease of the threshold**

## what is the dissociation mechanism

- Rate of escape into the continuum
- binding energy
- T >> EQQ **screening **
- weak coupling
- continuum dominates
- all states modified
- T << EQQ **gluo-effect**
- strong coupling
- discrete states dominate
- ground state unaffected
-         T>Tc gluon sector dominates
-                  talk by F.Karsch

-          Kharzeev,McLerran, Satz 95

-   Kharzeev,AM, in prep

- Shuryak 78
- Bhanot, Peskin 79

## conclusion

- temperature-dependent screened potentials inconsistent with lattice QCD
- screening not responsible for quarkonia dissociation
- we are in the strong coupling regime where dissociation is due to gluons
-                             stay tuned, you’ll here more soon ...

## thanks a lot

- Péter Petreczky
- Dima Kharzeev
- Jorge Casalderrey-Solana

## c correlator

**Notes:**
lattice: no change until ~1.5Tc 
 potential model: increase due to threshold reduction 
     then decrease due to amplitude reduction
no agreement with lattice 

## non-relativistic Green’s function

- AM, P.Petreczky, hep-ph/0606053
- AM, P.Petreczky, J.Casalderrey-Solana, in prep

-   another way to obtain the spectral function
-                               include many body effects

**Notes:**
to overcome some issues with the spectral function design .. many body effects included