1. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 1 Resonances at RHIC and LHC Christina Markert University of Texas at Austin Motivation Resonances in hadronic phase System size/energy dependence Chiral symmetry restoration Leptonic decays, jets Resonances at the LHC Conclusions

2. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 2 Why Resonances ? Resonances are: Excited state of a ground state hadron. With same quark content but higher mass Decay strongly  short life time (~10 -23 seconds = few fm/c ), width = reflects lifetime Why Resonances?: Short lifetime  decay in medium Surrounding nuclear medium may change resonance properties Chiral symmetry restoration: Dropping mass -> width, branching ratio  = h/t Resonance Lifetime [fm/c] decays  e +  e -    p     p+K   e +  e - J  ccbar)  e +  e -   +  -  bbbar  e +  e -   +  -

3. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 3 Resonance formation in heavy ion reactions 1.) Resonances created at the beginning of the collision before it melts into a Quark Gluon Plasma (QGP)  potentially survive in partonic matter (QGP) 2.) Most resonances are formed when partonic matter transitions back into hadronic matter  sensitive to phase transition properties i.e. deconfinement, chiral symmetry restoration. 3.) Sensitive to hadronic matter due re-scattering and regeneration 3.) Pre equili- brium QGP Mixed phase ProtonsLambdas Lambda Delta 00 direct ** 00  % of total yield 1.) 2.) Hadron gas temperature TcTc TiTi T kin T chem

4. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 4 Resonances are the Key Probe for QCD Phase Transition(s) Because of lifetime and strong interactions with the medium, light vector mesons are the only probe of chiral symmetry restoration Because of color screening in the medium, heavy vector mesons are the most sensitive probe of deconfinement conditions BR K+K- /BR e+e-

5. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 5 Resonance response to medium Tc partons hadrons Baryochemical potential (Pressure) Temperature Quark Gluon Plasma Hadron Gas T Freeze Shuryak QM04 Resonances below and above Tc:  Initial deconfinement conditions: Determine T initial through J/  and  state dissociation  Chiral symmetry restoration Mass and width of resonances  Hadronic phase evolution From hadronization (chemical freeze-out) to kinetic freeze-out.

6. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 6 Hadronic re-scattering and regeneration chemical freeze-out   p        p p kinetic freeze-out re-scattering regeneration  e+e+ e-e- leptonic decay hadronic decay  +X  Y (  *)  +X  Y (K*)  +X  Y (  *) UrQMD calculations Sascha Vogel, WWND 2006 hep-ph/0607242

7. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 7 Lifetime of nuclear medium T chemical  resonances time ~ 10 fm/c 2 particle correlation Partonic phase 

8. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 8 Interactions of resonances in hadronic medium [1] P. Braun-Munzinger et.al.,PLB 518 (2001) 41,priv. communication [2] Marcus Bleicher and Jörg Aichelin Phys. Lett. B530 (2002) 81. M. Bleicher and Horst Stöcker J. Phys.G30 (2004) 111. Life-time [fm/c] :     Regeneration/Rescattering cross section:  p)         Lifetime of hadronic medium: C. Markert, G. Torrieri and J. Rafelski, hep-ph/0206260 T= 160 MeV   > 4 fm/c (lower limit) UrQMD:  = 13 ± 3 fm/c Phys. Rev. Lett. 97 (2006) 132301 In agreement with UrQMD calculations [1] [2]

9. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 9 Resonance suppression (system size dependence) Phys. Rev. Lett. 97 (2006) 132301 Phys. Rev. C71 (2005) 064902 See S. Dash SQM2007 Life-time [fm/c] : K(892) = 4.0  =   (1520) = 13  (1020) = 45 STAR Preliminary A Lordanova SQM2007 From statistical model and blastwave fits of ,K,p

10. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 10 Resonance suppression (energy dependence) STAR preliminary Phys. Rev. C71 (2005) 064902 nucl-ex/0703033 See S. Dash SQM2007 Life-time [fm/c] K(892) = 4.0  (1020) = 45 STAR preliminary M. Bleicher et al. statistical errors only ! Less re-scattering at lower energies in peripheral collisions Same volume but, Lower density  smaller interactions cross section? Shorter hadronic lifetime  less hadronic interactions ?

11. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 11  (1520) signal in Cu+Cu 200 GeV Signal significance = 14  Study system size dependence of  (1520) Breit-Wigner-fit: m = 1514  1  4 MeV/c 2  = 18 MeV/c 2 (fixed) Particle Data Group: 1519.5  1.0 MeV/c 2 15.6  1.0 MeV/c 2

12. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 12 Resonance response to medium Tc partons hadrons Baryochemical potential (Pressure) Temperature Quark Gluon Plasma Hadron Gas T Freeze Shuryak QM04 Resonances below and above Tc:  Initial deconfinement conditions: Determine T initial through J/  and  state dissociation  Chiral symmetry restoration Mass and width of resonances ( e.g.  leptonic vs hadronic decay, chiral partners  and a 1 )  Hadronic time evolution From hadronization (chemical freeze-out) to kinetic freeze-out.

13. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 13 Measurable effects of chiral symmetry restoration  Mass shift  Width broadening  Branching ratio change

14. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 14 PDG K* 0 PDG K* ± STAR Preliminary MC No evidence for chiral symmetry restoration - small mass shifts in all system sizes K* 

15. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 15 Leptonic decay vs hadronic decay (PHENIX) QM2006 nucl-ex/0702022  (1020) yield from leptonic decay looks higher than from hadronic decay What happened to the mass and the width? leptonic decay hadronic decay What about leptonic decay contribution from regenerated resonances ?

16. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 16   near-side  STAR Preliminary near away Study Chiral Symmetry Restoration by comparing resonance production in event classes based on azimuthal distribution: We expect high p T resonances from the away side jet to be medium modified due to the high density and temperature of the partonic and pre-equilibrium hadronic medium CM: arXiv:nucl-ex/0706.0724 Resonances from jets to probe chirality

17. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 17 Formation of hadronic resonances (from jets) in a chiral medium side 1 side 2 near away Low ptHigh pt Near side No medium or late hadronic medium No medium Away side Late hadronic medium Partonic or early hadronic medium (depend on formation time) CSR ? Side 1&2 Late hadonic mediumEarly hadronic medium 5GeV/c 10GeV/c 20GeV/c Heavier particles of same momentum formed earlier High momentum particles formed later Need to determine the right momenta for trigger and resonance particle CM, R. Bellwied, I. Vitev in preparation

18. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 18 Hadron - resonance correlation in Au+Au  of h-  (1020) – C h-  (1020) mixed event QM2006 M.Horner STAR preliminary ZYAM = zero yield at minimum Hadron trigger p T > 4 GeV  (1020) ~ 0.9 GeV (  need higher p t ) Not corrected for acceptance Systematic BG normalization error not included Not corrected for v 2 51385±2369 64498±2400 No mass shift or width broadening visible  No evidence for chiral symmetry restoration at low pt resonances  Look at higher momentum resonances near - side away- side

19. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 19 Resonances at the LHC Higher initial temperature Tc:  Larger Partonic lifetime.  What is the hadronic lifetime ? hadronic decay of resonances Larger cross section of hard scattering processes Resonance Program requires: 1.) Good particle identification capability  ALICE detector PID: TOF, TPC, TRD, EMCAL 2.) And jet reconstruction capability: EMCAL + fast trigger  10-100 enhancement of jets

20. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 20 Resonances from Jets 30M di-jets (p T > 30 GeV/c) per year in EMCAL Resonance production from EMCAL triggered jets p T > 30 GeV/c (in one year) 500K  (1020) at p T = 4 GeV/c

21. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 21 Jet/hadron - resonances correlation (Pythia)  of h-  (1020) – C h-  (1020) mixed event Including realistic background of  (1020) resonance of sig/bg =2% hadron trigger p T > 15 GeV/c associated  (1020) p T > 4 GeV jet trigger p T > 30 GeV/c associated  (1020) p T > 4 GeV

22. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 22 Resonance Reconstruction at ALICE  (1020) A. Badalà- SQM07  (1520) Institutes at LHC – ALICE working on resonances ( ,K*,L*) INFN Sezione di Catania- Italy University of Athens, Greece  Hadronic lifetime

23. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 23 Conclusion Low momentum resonances provide information regarding the lifetime of the hadronic stage, and therefore determine indirectly the partonic lifetime of the system. The re-scattering cross section exhibits same system size dependency in Au+Au and Cu+Cu collisions. Lower collision energy results in less hadronic interactions. High momentum resonances from jets could be used as a tool to trigger on early produced resonances and test chiral symmetry restoration New STAR TOF detector will help to study higher p T resonance and leptonic decays.

24. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 24 LHC Higher initial temperature Hadronic lifetime ? Larger cross section for jet production

25. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 25 Time of Flight upgrade detector at STAR STAR: Time of Flight detector upgrade: PID at higher momentum Electron hadron separation Installation completed in 2-3 years STAR Experiment |1/β-1|<0.03 J.WU QM2006 Improves reconstruction of hadronic and leptonic decay channels : K*  K+ ,   p  *   p    e   e 

26. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 26 New idea: Resonances from jets to probe chirality Bourquin and Gaillard Nucl. Phys. B114 (1976) In p+p collisions resonances are predominantly formed in jets. jets ?

27. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 27 Regeneration might increase elliptic flow C. Nonaka, et al., Phys.Rev.C69: 031902,2004 Data suggest small regeneration for K* (need smaller errors !) minbias 200 GeV Au+Au Partonic resonance generation: Number of Constituent Quark (NCQ) scaling at intermediate p T (meson NCQ = 2) Hadronic resonance (re)generation: Regenerated resonances–final state interactions NCQ = 4 (  * =  +  =2+2) Phys. Rev. C71 (2005) 064902 Recombination model 15% increase

28. Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 2008 28 di-electron invariant mass distribution from PHENIX A significant excess is observed at low mass (m<1GeV/c) in Au+Au minimum bias p+pAu+Au minimum bias arXiv:0706.3034 [nucl-ex] Hugo Pereira Da Costa SQM2007 (Alberica Toia QM2005) What about leptonic decay contribution from regenerated resonances ? Talk by B. Llope The STAR Time of Flight detector (better PID)