Review of Signals of Deconfinement

Transcription

1 Review of Signals of Deconfinement Critical Point and Onset of Deconfinement Florence March Thanks to Burak Alver, Ed Wenger, Siarhei Vaurynovich, Wei LI Gunther Roland

2 Review of Signals of Deconfinement ( s Excitation Functions of Bulk Observables) c.f. D. Silvermyr (J/ψ), E. Scomparin (Leptons) Critical Point and Onset of Deconfinement Florence March Thanks to Burak Alver, Ed Wenger, Siarhei Vaurynovich, Wei LI Gunther Roland

3 Onset of Deconfinement Karsch et al Can this be traced in experiment? What are the conceptual challenges? Selection of results (some exciting, some boring) Gunther Roland Florence July 2006

4 Onset of Deconfinement Karsch et al Vary T Initial! Vary μ B Can this be traced in experiment? What are the conceptual challenges? Selection of results (some exciting, some boring) Phase diagram is 2-dimensional Vary T and/or μ B to enter QGP

5 Onset of Deconfinement Collision Energy RHIC SPS AGS Vary T Initial! Vary μ B System Size Two control parameters to vary initial conditions: Energy and System Size Phase diagram is 2-dimensional Vary T and/or μ B to enter QGP

6 1st Challenge: Moving across the phase diagram T chem and μ B at chemical freeze-out Collision energy varies T chem and μ B simultaneously c.f. Manninen, J. Cleymans

7 hep-ph/ , Cleymans et al Varying μ B at fixed s? Baryochemical Potential Freeze-out Temperature Strangeness Saturation

8 Variation of initial energy density PHENIX nucl-ex/ (PRC) Compilation by PHOBOS Nucl. Phys. A 757, 28 Cu+Cu PHOBOS QM 05 RHIC AGS SPS <E T >/hadron 1/τ v 2 1/τ Q sat ε BJ x10-20 ε = dn dy τ o m πr Bjorken 1982 T 2 dn ch /dη

9 2nd Challenge: Structures in s vs Fluctuations M. Bleicher, 97 E-by-E energy density ε BJ M. Bleicher, 97 Energy density in transverse plane Single event Fluctuations in initial conditions limit sharpness of structures vs collision energy

10 2nd Challenge: Structures in s vs Fluctuations M. Bleicher, 97 E-by-E energy density ε BJ Energy Density Fluctuations in initial conditions limit sharpness of structures vs collision energy PHENIX nucl-ex/ (PRC)

11 3rd Challenge: Net-Baryon/Meson Balance Fraction of produced hadrons in N ch SPS RHIC AGS Change from baryon- to meson dominated system over the energy range of interest!

12 Excitation Function: Total Multiplicities <N ch > <N ch >- (<K> +<p>) Compilation by PHOBOS nucl-ex/ nucl-ex/ PRC in press e+e- AGS c.f. P. Steinberg SPS RHIC c.f. C. Blume, M. Gazdzicki

13 Excitation Function: Total Multiplicities <N ch >/e+e- fit <N ch >- (<K> +<p>) e+e- SPS RHIC AGS Compilation by PHOBOS nucl-ex/ PRC in press Universality of entropy production At low energy, baryons carry away difference Increase in pion production due to change in DoF At low energy, baryons eat some of the pions

14 Excitation Function: Total Multiplicities <N ch >/e+e- fit <N ch >/e+e- fit e+e- AGS SPS RHIC Compilation by PHOBOS nucl-ex/ PRC in press c. log 2 (s) Wit Busza, Zakopane 04 A+A by itself can be fit with log 2 (s) Structure at SPS (and therefore interpretation) depends on context (e.g. comparison to e+e-, treatment of baryons)

15 Fluctuations as Deconfinement Signal Jeon, Koch PRL (2000) hep-ph/ Asakawa, Heinz, Mueller PRL (2000) hep-ph/ DoF of Medium? Net Charge/Δy Fluctuations Charge/DoF Fluc s change from 1-2 (QGP) to 4 (Pion Gas) Fluctuations frozen b/c charge conservation Diffusion vs Expansion timescale Ratio N + /N - Event-by-event distribution of net charge ratio

16 Excitation Function: Charge Fluctuations Plot from Claude Pruneau RHIC Users meeting workshop 04 NA49, PRC (2004) PHENIX: PRL (2002) QGP Little (no) s dependence of charge fluctuations

17 Hadron Production in Clusters PHOBOS, PRC in press c.f. C. Loizides, W. Li 0-20% central PHOBOS 200 GeV Au+Au effective cluster size for 200 GeV Au+Au Cluster in Δη,Δφ space via 2-particle correlations (pythia GeV, η<3) Lesson: Hadronization cannot be ignored in discussion of early stage fluctuations

18 4th Challenge: Rapidity Scales Clustersize Δy SPS NA49 Acc. Clustersize Rapidity gap RHIC STAR Acc. Clustersize < Rapidity gap Acc. > Clustersize << Rapidity gap LHC CMS

19 Excitation Function: Charge Fluctuations Plot from Claude Pruneau RHIC Users meeting workshop 04 NA49, PRC (2004) PHENIX: PRL (2002) QGP Small s dependence of charge fluctuations?

20 Excitation Function: Transverse Momentum Temperature L. Van Hove Phys.Lett.B118:138,1982Text Entropy Density

21 Excitation Function: Momentum Spectra Compilation by NA49 Plot from Claudia Hoehne, QM 05 filled symbol: particle open symbol: antiparticle The Kink - Structure in energy dependence of <m T > - Reminiscent of Van Hove s T vs σ prediction - Surprisingly difficult measurement Decay corrections, PID acceptance

22 5th Challenge: Experimental Systematics Compilation by NA49 Plot from Claudia Hoehne, QM 05 filled symbol: particle open symbol: antiparticle The Kink Text Experimental systematic errors underestimated Structure at AGS/SPS boundary

23 Excitation Function: <β T > PHENIX Whitepaper STAR compilation, Plot from T. Nayak T th [GeV] <β r > [c] <m T > decomposed in T th and <β T > at freeze-out Connection to initial temperature?

24 Excitation Function: Elliptic flow Low Density Limit: STAR, PRC (2002) Voloshin, Poskanzer, PLB (2000) Heiselberg, Levy, PRC , (1999) c.f. R. Snellings, R. Lacey NA49 PRC C (2003) Cu+Cu Hydro- Limit Au+Au Cu+Cu: PHOBOS QM 2005 Participant Eccentricity provides universal scaling Approach to equilibrium or sampling different regions of EOS? Collapse of proton flow at 40AGeV? c.f. H. Stoecker

25 Excitation Function: Strangeness production vs s The Horn NA49 Phys.Rev.C66:054902,2002 Plot from M. Mitrowski, SQM 06

26 Strangeness production vs s A+A Becattini et al. A+A e + e - (Canonical Ensemble) The Horn A+A e + e - (Canonical Ensemble) NA49 Phys.Rev.C66:054902,2002 Plot from M. Mitrowski, SQM 06

27 Excitation Function: Strangeness production vs s The Horn Challenges: Net-Baryon/meson balance? Rapidity scales (mid-y vs 4π)? Sharp structures in finite systems? Experimental confirmation? NA49 Phys.Rev.C66:054902,2002 Plot from M. Mitrowski, SQM 06

28 Strangeness excitation function AGS SPS AGS SPS RHIC Text RHIC

29 Excitation Function: K/π Fluctuations NA49, Christof Roland, QM 04 STAR, Supriya Das, SQM 06 The Horn AGS? SPS NA49 Preliminary RHIC STAR Preliminary Connection to initial temperature?

30 Excitation Function: K/π Fluctuations Normalized by dn/dy or (dn/dy) 1/2 AGS? RHIC AGS? RHIC SPS SPS Scaling by dn/dy or (dn/dy) 1/2 does not work over full energy range Physics changes

31 Excitation Function: Momentum Fluctuations Compilation by STAR STAR PRC (2005) The Kink SPS CERES AGS? RHIC STAR Central A+A Monotonic energy dependence over measured range No results near kink region

32 Excitation Function: Momentum Fluctuations STAR preliminary STAR Scaling: Connection between <pt>, N, fluctuations? STAR Σ pt CERES Connection to 2-particle correlations Interpretation connected to choice of variables

33 Summary Structure in hadronic observables vs s? Yes - in AGS/SPS Energy range K/π K/π fluctuations <m T > N ch Charge Fluctuations

34 Challenges Summary cntd. Moving across phase diagram Rapidly changing baryon/meson ratio Location of structure vs context Fixed vs varying rapidity scales Cluster width, rapidity width vs mass Finite size system, fluctuations: Sharp structures possible? Experimental verification FAIR, RHIC c.f. P. Senger, H.G. Ritter, P. Sorensen, J. Mitchell, M.G.