1. Formation and decay of resonances Motivation Formation time Resonance Correlation Summary and Future Plans Motivation Formation time Resonance Correlation Summary and Future Plans Christina Markert University of Texas at Austin Christina Markert 1 25th WWND Big Sky Montana 1-8 Feb 2009

2. Resonance response to medium Temperature Quark Gluon Plasma Hadron Gas T Freeze Shuryak QM04  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. Baryochemical potential partons Tc hadrons Christina Markert 225th WWND Big Sky Montana 1-8 Feb 2009

3. Medium modified resonance (signatures) A fundamental symmetry of QCD is chiral symmetry. Chiral symmetry is broken by large dynamical mass in confinement  deconfinement leads to partial restoration. Lattice QCD shows that deconfinement and chiral symmetry restoration (CSR) happens at the same temperature Chiral symmetry Restored Christina Markert 325th WWND Big Sky Montana 1-8 Feb 2009

4. Chiral symmetry restoration signal ? Christina Markert 425th WWND Big Sky Montana 1-8 Feb 2009 NA60 Medium unmodified Medium modified Width broadening of rho meson In dimuon spectrum

5. 5 Leptonic decay vs hadronic decay  (1020) yield from leptonic decay looks higher than from hadronic decay What happened to the mass and the width? Effective mass drops:  hadronic decay closes up.  Increase of BR ratio e+e-e+e- K+K-K+K- 25th WWND Big Sky Montana 1-8 Feb 2009 Christina Markert What is the contribution of decay from regenerated resonances from the later hadronic phase ?

6. 6 The general idea: resonances from jets (CM, R. Bellwied, I.Vitev, Phys.Lett.B669:92-97,2008)  We want early produced resonances and decay in chirally restored medium  resonances from jets  Is it possible to have hadron production prior to hadronization, i.e. can there be a mixed phase of degrees of freedom (partons/hadrons) ?  If these hadrons are resonances, can they also decay within the partonic phase or the dense hadronic phase and thus be medium modified ? partonic medium partonic medium hadrons/ resonances hadrons/ resonances

7. Resonance formation in heavy ion reactions 1.) Most resonances (u,d,s) are formed when partonic matter transitions back into hadronic matter  sensitive to phase transition properties i.e. chiral symmetry restoration. 2.) Formation of resonances in hadronic matter due to regeneration 3.) Resonances created from a jet within the QGP phase (mixed dof Phase)  potentially survive in partonic matter (QGP) 2.) Pre equili- brium QGP Mixed Phase 3.) 1.) Hadron gas temperature TcTc TiTi T kin T chem Christina Markert 7 25th WWND Big Sky Montana 1-8 Feb 2009 Mixed dof Chiral symmetry restored

8. 8 The concept of formation time  In string fragmentation as well as general QM considerations (e.g. Heisenberg’s uncertainty principle) the formation time of a hadron is given by:  A detailed calculation in light cone variables shows a modification due to short formation length for high z hadrons (z  1)   o ~ 1 fm/c : proper formation time in hadrons rest frame E : energy of hadron m: mass of hadron E/m =   high energy particles are is produced later   heavy mass particles are produced earlier large z (=p h / p q ) = Resonance is leading particle in jet  shortens formation time CM, R. Bellwied, I. Vitev Phys.Lett.B669:92-97,2008.

9. Formation of hadronic resonances (from jets) CM, R. Bellwied, I. Vitev Phys.Lett.B669:92-97,2008. Heavier particles of same momentum formed earlier High momentum particles formed later Christina Markert 925th WWND Big Sky Montana 1-8 Feb 2009 for  at RHIC

10. 10 Comparing resonance formation time to QGP lifetime  What is the proper  0 ? (QGP start time)   0 requires thermalization which is an open issue at RHIC and LHC.  General approach  0 ~ 1/ ( RHIC = 450 MeV/c, LHC = 850 MeV/c)  Leads to  0 (RHIC)=0.44 fm/c and  0 (LHC)=0.23 fm/c  What is the proper QGP lifetime ?  Upper limit based on longitudinal Bjorken expansion   QGP =  0 (T 0 /T c ) 3 with T 0 (  0,RHIC)= 435 MeV and T 0 (  0, LHC)= 713 MeV, T c = 180 MeV   QGP (RHIC) = 6.2 fm/c,  QGP (LHC) = 14 fm/c  RHIC result slightly higher than data driven partonic lifetime estimate based on HBT and resonances (  QGP (RHIC) ~ 5 fm/c)

11. Formation Time of Resonances At LHC the momentum range of resonances decaying inside QGP is extended to higher momentum due to longer QGP lifetime RHIC LHC  (1020): RHIC p T = [3-10] GeV LHC p T =[2-20] GeV Christina Markert 1125th WWND Big Sky Montana 1-8 Feb 2009

12. 12 Lifetime of hadronic resonances  Problem: if we want to measure medium modification of a hadronic resonances through the partonic medium the resonance does not only have to be formed but it also needs to decay in the partonic or the dense hadronic medium.  short lived resonances  But too short a lifetime makes reconstruction difficult (broad states):  Resonances are medium modified  short lifetime (e.g. Holt & Haglin, J. Phys. G31 (2005)) modified K*,  *,  *,  are good candidates  Dynamic problem: The resonance formation time will change with mass and momentum. lifetime

13. 13 Triggered resonance quadrant correlation analysis side 1 side 2 near away Low ptHigh pt near side No medium or late hadronic medium No medium (reference data) away side Late hadronic medium Partonic or early hadronic medium (depend on formation time) CSR ? side 1&2 Thermal hadonic medium Thermal hadronic medium near side1 away side2 hadron-resonance correlation

14. Hadron –  (1020) correlation in Cu+Cu Hadron trigger p T > 3 GeV (2.5M)  (1020) asso p T =1-2 GeV Not corrected for v 2 First bin in delta phi STAR preliminary No evidence for mass shifts and width broadenings on the away-side Most  (1020) are from thermal medium  Need higher p T resonances Width: 6.0±0.7 MeV Width: 7.2±0.9 MeV M(K + K - ) GeV/c 2 Christina Markert 1425th WWND Big Sky Montana 1-8 Feb 2009 HQ2008

15. Time of Flight detector upgrade at STAR Full installation completed in next years (now 65%) PID at higher momentum Electron hadron separation Improves reconstruction of hadronic and leptonic decay channels : K*  K+  (2.5),   p   *   p (11)    e   e  Christina Markert 1525th WWND Big Sky Montana 1-8 Feb 2009

16. 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 Christina Markert 1625th WWND Big Sky Montana 1-8 Feb 2009

17. K* and  at the LHC (ALICE) Christina Markert 1725th WWND Big Sky Montana 1-8 Feb 2009 Pt jet = 50-60 GeV K* Francesco Blanco (Houston/Catania) Jet P T = 50-60 GeV K* TPC acceptance (|  |<0.9) Jet P T = 50-60 GeV  (1020) TPC acceptance (|  |<0.9)

18. Summary High momentum resonances from jets could be used as a tool to trigger on early produced resonances and test chiral symmetry restoration New detector upgrades at RHIC, and LHC experiments, will help to study higher p T resonances in more detail to study chiral symmetry restoration. (Also investigate jet triggered leptonic decays) High momentum resonances from jets could be used as a tool to trigger on early produced resonances and test chiral symmetry restoration New detector upgrades at RHIC, and LHC experiments, will help to study higher p T resonances in more detail to study chiral symmetry restoration. (Also investigate jet triggered leptonic decays) Christina Markert 1825th WWND Big Sky Montana 1-8 Feb 2009