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Resonances and Correlations in Heavy Ion C ollisions

Resonances and Correlations in Heavy Ion C ollisions. Christina Markert, Kent State University for the STAR Collaboration. Resonances in Medium Rescattering and Regeneration Hadronic vs Leptonic Decay Resonances at hight p T Conclusions. K -. K *. p +. Au+Au. K -. K *. K * ?.

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Resonances and Correlations in Heavy Ion C ollisions

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  1. Resonances and Correlations in Heavy Ion Collisions Christina Markert, Kent State University for the STAR Collaboration Resonances in Medium Rescattering and Regeneration Hadronic vs Leptonic Decay Resonances at hight pT Conclusions Christina MarkertBreckenridge, Feb 6-11, 2005

  2. K- K* p+ Au+Au K- K* K*? p+ Hadronization Chemical freeze-out Rescattering/regeneration Thermal freeze-out Resonances in Medium Proposed measurements Collision systems: p+p and A+A collisions Leptonic and hadronic channels: e.g. f,( r)  e++e- , m++m- , K++K- Hadronization Hadrons are formed from quarks Chemical freeze-out: T~170MeV end of inelastic interactions particle yields Kinetic freeze-out: T~100MeV end of elastic interactions particle spectra Christina MarkertBreckenridge, Feb 6-11, 2005

  3. K- p (1520) (1385)  - p - Resonance Reconstruction in STAR TPC Energy loss in TPC dE/dx End view STAR TPC p dE/dx K  e momentum [GeV/c] • Identify decay candidates • (p, dedx, E) • Calculate invariant mass K(892)  + K  (1020)  K + K (1520)  p + K S(1385)  L + p X(1530)  X + p Christina MarkertBreckenridge, Feb 6-11, 2005

  4. ΦK+K- Resonance Signals in p+p and Au+Au Collisions K(892) STAR Preliminary f(1020) (1520) (1385)  p+p Au+Au Christina MarkertBreckenridge, Feb 6-11, 2005

  5. Resonance momentum Spectra K(892) S(1385) and L(1520) STAR Preliminary Integrated momentum distribution  yields Christina MarkertBreckenridge, Feb 6-11, 2005

  6. Thermal model UrQMD Rescattering and Regeneration Life-time [fm/c] : ++ = 1.7 K(892) = 4 S(1385) = 5.7 L(1520) = 13  (1020) = 45 K* and L* show rescattering D++ and S* show regeneration Regeneration cross section: s(K+p) <s (K+p) < s (p+p), s (L+p) ? L* K* D++ S* P. Braun-Munzinger et.al., PLB 518(2001) 41 Marcus Bleicher and Jörg Aichelin Phys. Lett. B530 (2002) 81. M. Bleicher and Horst Stöcker J. Phys.G30 (2004) 111. Christina MarkertBreckenridge, Feb 6-11, 2005

  7. Particle spectra from Thermal Model W. Florkowski, SQM2004 T = 165.7 MeV μB = 27.9 MeV Signal loss for K* in low momentum region due to rescattering Regeneration also in low momentum region (D,r) Christina MarkertBreckenridge, Feb 6-11, 2005

  8. Signal Loss in low pT Region (UrQMD) Marcus Bleicher and Jörg Aichelin Phys. Lett. B530 (2002) 81-87. M. Bleicher and Horst Stöcker .Phys.G30 (2004) 111. pT spectrum flatter increase of <pT> Christina MarkertBreckenridge, Feb 6-11, 2005

  9. AuAu pp pT changes due to rescattering ? Inverse slope increase from p+p to Au+Au collisions. UrQMD predicts signal loss at low pT due to rescattering of decay daughters.  Inverse slopes and mean pT are higher. UrQMD has long lifetime (Dt 5-20fm/c) Christina MarkertBreckenridge, Feb 6-11, 2005

  10. Tch freeze-out Tkin freeze-out “Life-time” from Resonances Tch from thermal model fit, Tkin from Blast-Wave-Fit to p, K and p “Life-time” nearly constant in peripheral and central Au+Au collisions Resonances with more rescattering than regeneration: K*, L(1520)   > 4 fm/c G. Torrieri and J. Rafelski, Phys. Lett. B509 (2001) 239 Christina MarkertBreckenridge, Feb 6-11, 2005

  11. NA49 Pb-Pb T (MeV) NA60 In-In NA50 Pb-Pb f Meson at SPS CERES: f K+K-, e+e- [A. Marin SQM2004] f m+m- Hadronic channel: less signal in low pt lower yield (factor 4±2) Rob Veenhof Christina MarkertBreckenridge, Feb 6-11, 2005

  12. UrQMD: K*(892) (1520)  SPS (17 GeV) 66% 50% 26% RHIC (200GeV) 55% 30% 23% Hadronic Phase after Chemical Freeze-out signal loss in low momentum region  Increase of inverse slope • Signal loss in UrQMD = 26% • Data: yield factor of 4±2 difference • for hadronic to leptonic channel. • Additional in medium modification • of resonance at early stage ? • Theory can describes data: • K. Haglin et. al, E. Kolomeitsev et.al • f shorter lifetime in medium • decay rate increased with in-medium kaons  f m+m- from early decay  f K+K- from late decay Christina MarkertBreckenridge, Feb 6-11, 2005

  13. Decaytime for Hadronic vs Leptonic Channel UrQMD • all decay • - measured • all decay • - measured l+l- p+p- Short lifetime resonances: Leptonic signal  signal from early decay Hadronic signal  signal from late decay (D later than r) Christina MarkertBreckenridge, Feb 6-11, 2005

  14. Estimate the Regeneration Probability Estimate of available energy for re-feeding at different reaction stages: D r • can re-created until end of the reaction (T kin ~ 90MeV) • re-creation is only possible near chemical freeze-out Marcus Bleicher, SQM2004 Christina MarkertBreckenridge, Feb 6-11, 2005

  15. sNN = 200 GeV STAR Preliminary Δ++ Width GeV/c2 AuAu dNch/dη Delta Resonance from late decay STAR preliminary 30-50% Au+Au Δ++ PDG Minv p+p+ [GeV/c2] • +nucleon propagation in medium + fireball conditions (T, r) • (1232) from: Tkin=100 MeV • (1232) width increase Hendrik von Hees: HotQuarks2004 (Hees and Rapp nucl-th/0407050) Christina MarkertBreckenridge, Feb 6-11, 2005

  16. 2 measured p’s are coming from D decays p Regeneration increases the number of primary particles that get used by a resonance p D p D p p p p Feed down from Resonances S* • J.Letessier, J.Rafelski, • Hadrons and Quark Gluon Plasma, • Cambridge Monographs STAR direct L • Thermal model+STAR data • Tch=160 MeV • 32% primary Lambdas • ~30% primary Protons S0 Tch = 160 MeV See also Levente Molnar’s talk • Large fraction of stable particles • come from resonance decays. • Rescattering and regeneration • Less primary particles • Momentum distribution changes Christina MarkertBreckenridge, Feb 6-11, 2005

  17. Magali.Estienne@subatech.in2p3.fr Kinetic freeze-out STAR PRELIMINARY Au+Au at √sNN=200GeV X,W freeze out earlier ? SQM2004 - Cape Town – September 2004 Christina MarkertBreckenridge, Feb 6-11, 2005

  18. Regeneration of X(1530)?  see late X ? X + p  X(1530) regeneration cross section ? Large regeneration cross section For D and S(1385) Christina MarkertBreckenridge, Feb 6-11, 2005

  19. Resonances from Jets in p+p ? Thermal <pT> prediction for T = 170 MeV, b=0 High mass particles from more jet like events Christina MarkertBreckenridge, Feb 6-11, 2005

  20. Resonances in Medium (Jets vs Bulk Matter) • Resonances as: • Particle in jet • Bulk particle • same side/away side Snap shot from early stage of collision Resonance in jet Resonance from bulk High luminosity, large acceptance, particle id up to 30 GeV. RHIC II (idea of a new detector R2D) Talks by Angelika Drees, Rene Bellwied and John Harris Christina MarkertBreckenridge, Feb 6-11, 2005

  21. Conclusions • Strong interacting hadronic medium after • chemical freeze-out. •  Thermal models do not describe all resonance yields. •  Rescattering and regeneration of resonances. •  Regeneration probes hadronic cross sections of heavy baryons. •  “Life-time” between freeze-outs > 4 fm/c • Medium modification of resonances. •  f yield in leptonic and hadronic channel at SPS • may give indication of width broadening of phi in medium. •  Width broadening of D++observed at RHIC energies in • Au+Au collisions. • Large fraction of particles coming from • resonance decays • Could affect kinematics of ’primordial’ particles. • High pT Resonances my probe the medium • at early stage. Christina MarkertBreckenridge, Feb 6-11, 2005

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