# Presentation: 865909

## The Effect of Dynamical Parton Recombination on Event-by-Event Observables

- Marcus Bleicher & Stephane Haussler
- Institut für Theoretische Physik
- Goethe Universität Frankfurt
- Germany

- Marcus Bleicher, ISMD Berkeley 08/2007

## Thanks

-  Elena Bratkovskaya
-  Manuel Reiter
-  Sascha Vogel
-  Xianglei Zhu
-  Horst Stoecker
- Timo Spielmann

-  Katharina Schmidt
-  Hannah Petersen
-  Stephane Haussler
-  Daniel Krieg
-  Benjamin Lungwitz

- Marcus Bleicher, ISMD Berkeley 08/2007

## Outline of the talk

- Introduction
- The Quark-Molecular Dynamics
- Charge fluctuations
- Baryon-strangeness correlations
- Charge transfer fluctuations (see backup)
- Summary

- Marcus Bleicher, ISMD Berkeley 08/2007

## Motivation

- At **RHIC**: look for signals of freely moving partons.(D, CBS,)At **FAIR/SPS**:look for the mixed phase and the onset of deconfinement(kp

- E. Bratkovskaya, M.B. et al., PRC 2005

- Marcus Bleicher, ISMD Berkeley 08/2007

## Fluctuations are THE tool!?

- Fluctuations might provide information on
- 	- deconfinement/confinement- correlation length- thermalization- nature of the QGP- critical point
- Is it that easy?- finite time and volume- non-equilibrium- hadronization

- Marcus Bleicher, ISMD Berkeley 08/2007

## Scaled variances

- Non-trivial structures
- Detailed non-equilibrium studies necessary

- Lungwitz, Bleicher, in preparation

- 4pi

- forward

- Marcus Bleicher, ISMD Berkeley 08/2007

## The tool: qMD

- qMD : Quark Molecular Dynamics	 (a toy model for hadronization)
-  out-of-equilibrium transport model,   (Vlasov equation)
-  provides a hadronization prescription
-  essentially realizes a dynamical   quark recombination approach

- Marcus Bleicher, ISMD Berkeley 08/2007

## Quark Molecular Dynamics

- Marcus Bleicher, ISMD Berkeley 08/2007

## Trajectories

- Marcus Bleicher, ISMD Berkeley 08/2007

## Hadronization procedure

- Marcus Bleicher, ISMD Berkeley 08/2007

## Some properties: equilibrium

- Marcus Bleicher, ISMD Berkeley 08/2007

- For ‘real’ physics use UrQMD initial state
- dissolve strings into ‘free’ quarks
- evolve system with qMD

- Marcus Bleicher, ISMD Berkeley 08/2007

## Entropy consideration

- <N>

- <m>

- Marcus Bleicher, ISMD Berkeley 08/2007

## Entropy and recombination

- Marcus Bleicher, ISMD Berkeley 08/2007

## The idea behind conserved charge fluctuations

- Marcus Bleicher, ISMD Berkeley 08/2007

## Fluctuations and suceptibilities

- Marcus Bleicher, ISMD Berkeley 08/2007

## Comparison to lQCD (I)

- Marcus Bleicher, ISMD Berkeley 08/2007

## Comparison to lQCD (II)

- Marcus Bleicher, ISMD Berkeley 08/2007

- Hadron gas seems to be pretty similar to QGP...

- ( A. Majumder et al, Phys. Rev.C 74 (2006) 054901 )

- Marcus Bleicher, ISMD Berkeley 08/2007

## Charge ratio fluctuations

- Marcus Bleicher, ISMD Berkeley 08/2007

- Pion gas, D ~ 4

- Quark gas, D ~ 1

- Marcus Bleicher, ISMD Berkeley 08/2007

## Can one observe the fluctuations in the initial state?

- See e.g. Shuryak et al, Phys.Rev.C63:064903,2001

- Marcus Bleicher, ISMD Berkeley 08/2007

## Experimental results

- Marcus Bleicher, ISMD Berkeley 08/2007

## Recombination and fluctuation

- parton fraction

- y=1

- Au+Au@200 AGeV

- Marcus Bleicher, ISMD Berkeley 08/2007

## See also...

- Bialas: Recombination blur ratio 			       fluctuations (Phys.Lett.B532:249-251,2002)
- Nonaka: Recombination blurs ratio 	                 fluctuations (Phys.Rev.C71:051901,2005 )
- Ma: Hadronization blurs ratio fluctuations(SQM 2007)
- Present work:

- Marcus Bleicher, ISMD Berkeley 08/2007

## Baryon-Strangeness Correlations

- Marcus Bleicher, ISMD Berkeley 08/2007

## Time evolution

- y=1

- Au+Au@200 AGeV

- Marcus Bleicher, ISMD Berkeley 08/2007

## Conclusions

- Marcus Bleicher, ISMD Berkeley 08/2007

## Additional slides

- Marcus Bleicher, ISMD Berkeley 08/2007

- Marcus Bleicher, ISMD Berkeley 08/2007

## Charge transfer fluctuations

- Marcus Bleicher, ISMD Berkeley 08/2007

## qMD results on kappa

- Au+Au@200 AGeV

- Marcus Bleicher, ISMD Berkeley 08/2007