Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April Why Resonances ? Resonances are: Excited state of a ground state hadron. With same quark content but higher mass Decay strongly  short life time (~ 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 -   +  -

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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-

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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.

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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/

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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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/ T= 160 MeV   > 4 fm/c (lower limit) UrQMD:  = 13 ± 3 fm/c Phys. Rev. Lett. 97 (2006) In agreement with UrQMD calculations [1] [2]

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April Resonance suppression (system size dependence) Phys. Rev. Lett. 97 (2006) Phys. Rev. C71 (2005) 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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April Resonance suppression (energy dependence) STAR preliminary Phys. Rev. C71 (2005) nucl-ex/ 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 ?

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April  (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:  1.0 MeV/c  1.0 MeV/c 2

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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.

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

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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April Leptonic decay vs hadronic decay (PHENIX) QM2006 nucl-ex/  (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 ?

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April   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/ Resonances from jets to probe chirality

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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 ± ±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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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  enhancement of jets

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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.

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

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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 

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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 ?

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April Regeneration might increase elliptic flow C. Nonaka, et al., Phys.Rev.C69: ,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) Recombination model 15% increase

Christina Markert 24th Winter Workshop on Nuclear Dynamics, South Padre Island, Texas,5-12 April 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: [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)