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Resonance Production in RHIC Collisions

Resonance Production in RHIC Collisions. Christina Markert Kent State University. for the STAR Collaboration. Motivation Resonance in hadronic phase Time R AA and R dAu Elliptic flow v 2 Summary. T chemical. T chemical.

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Resonance Production in RHIC Collisions

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  1. Resonance Production in RHIC Collisions Christina Markert Kent State University for the STAR Collaboration • Motivation • Resonance in hadronic phase • Time • RAA andRdAu • Elliptic flow v2 • Summary Christina Markert Hot Quarks, Sardinia, Mai 2006

  2. Tchemical Tchemical Lifetime of Nuclear Medium Dt > 4 fm/c resonances Au+Au t ~ 10 fm/c (HBT) Partonic phase  < 6 fm/c C. Markert, G. Torrieri, J. Rafelski, hep-ph/0206260 + STAR  delta lifetime > 4fm/c Christina Markert Hot Quarks, Sardinia, Mai 2006

  3. p L* K p p L* K Time in Heavy Ion Reactions p+p • p+p interactions: • No extended initial medium • Chemical freeze-out (no thermalization) • Kinetic freeze-out close to the chemical freeze-out Particle yields Particle spectra Au+Au • Au+Au interactions: • Extended hot and dense phase • Thermalization at chem. freeze-out • Kinetic freeze-out separated from • chemical freeze-out Hot and dense medium time Christina Markert Hot Quarks, Sardinia, Mai 2006

  4. Resonance Signals in p+p and Au+Au collisions from STAR p+p  p+p Au+Au K(892) (1385) Au+Au K(892)  K+  D(1232)  p+   (1020)  K + K (1520)  p + K S(1385)  L + p D++ p+p (1020) p+p p+p (1520) Au+Au Au+Au Christina Markert Hot Quarks, Sardinia, Mai 2006

  5. Interactions of Resonance in Hadronic Nuclear Medium Life-time [fm/c] : K(892) ~ 4.0 S(1385) ~ 5.7 L(1520) ~ 13  (1020) ~ 44 Dt Preliminary UrQMD Dt =10±3 fm/c [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. K* and L* show rescattering S* shows regeneration Regeneration/Rescattering cross section: s(K+p) <s (K+p) < s (L+p) ? L* K* S* Christina Markert Hot Quarks, Sardinia, Mai 2006

  6. preliminary L+X Y K+X Y S+X Y Regeneration Cross Sections Production channel for measured resonances: UrQMD calculations S+p  L(1520) K+p  K* N+K L(1520) L+p  S(1385) Regeneration/Rescattering cross section: s(S+p) < s (K+p) < s (L+p) ? L* K* S* Sascha Vogel, San Diego Winter Workshop 2006 Christina Markert Hot Quarks, Sardinia, Mai 2006

  7. RAA of Resonances (with rescattering) • K(892) more suppressed in AA than Ks0 • K(892) are lower than Ks0 (and f) • pt < 2.0 GeV factor of 2 Christina Markert Hot Quarks, Sardinia, Mai 2006

  8. Nuclear Modification Factor RdAu • K* is lower than Kaons in low pt d+Au no medium  no rescattering why K* suppression in d+Au ? • S* follows h+- and lower than protons . Christina Markert Hot Quarks, Sardinia, Mai 2006

  9. Preliminary Medium in d+Au ? L*: No rescattering in hadronic d+Au medium K* : Rescattering in hadronic d+Au medium ??? Christina Markert Hot Quarks, Sardinia, Mai 2006

  10. Low mean pT ≠ early freeze-out ? Fit to X and W Higher T kin and lower <bT> Resonance are regenerating close to kinetic freeze-out  we measure late produced S(1385) How is elliptic flow v2 effected ? v2= signal for early partonic interactions Christina Markert Hot Quarks, Sardinia, Mai 2006

  11. p p p p D* kinetic freeze-out p re-scattering chemical freeze-out p D* p K p regeneration time Effects on v2 of and from Resonances • v2 of pions: • Primary produced (30%) • Early resonance decay • Late resonance decay • v2 of resonances: • Early resonances • Regenerated resonances Christina Markert Hot Quarks, Sardinia, Mai 2006

  12. Elliptic flow v2 pT (GeV) Resonances v2 and NCQ Scaling Test C. Nonaka, et al., Phys.Rev.C69: 031902,2004 • Fluid dynamics calculations (zero viscosity) describe data pT < 2 GeV Do Resonances show same mass splitting ? • Number of Constituent Quark (NCQ) scaling at intermediate pT (2= mesons, 3= baryons)  indication of partonic degrees of freedom Regenerated resonances–final state interactions NCQ = 5 (S* = L +p =3+2) Christina Markert Hot Quarks, Sardinia, Mai 2006

  13. Elliptic flow Reaction plane f elliptic flow v2 in minbias Au+Au 200 GeV f pT = 1.0-1.5 GeV v2=12±2% dN/d(f-) f signal 2(f-) Inv mass (K+ K-) v2=16±0.04% dN/d(f-) Bg of f invmass 2( f-) Inv mass (K+ K-) Kaon p < 0.6 GeV Christina Markert Hot Quarks, Sardinia, Mai 2006

  14. v2 of phi resonance in Au+Au 200GeV STAR Preliminary f has long lifetime 45fm/c  less rescattering or regeneration Elliptic flow of Φ-meson is close to Ks Delta resonance ? Christina Markert Hot Quarks, Sardinia, Mai 2006

  15. Summary • Hadronic resonances help to separate hadronic from partonic lifetime • Ranking of rescattering over regeneration cross section in medium. • Low pt RAA behavior confirms rescattering hypothesis. (RdAu puzzle?) • v2 of long lived resonances seems to follow stable particle trends (confirmation of NCQ scaling) Christina Markert Hot Quarks, Sardinia, Mai 2006

  16. For Raymond Christina Markert Hot Quarks, Sardinia, Mai 2006

  17. Preliminary Au+Au p+p Signal Loss in Low pT Region K(892) flow pT 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 T and mean pT are higher. Flow would increase pT of higher masse particles stronger. Christina Markert Hot Quarks, Sardinia, Mai 2006

  18. Temperature and “Life-time” fromK* and L* Life time: K(892) = 4 fm/c L(1520) = 13 fm/c G. Torrieri and J. Rafelski, Phys. Lett. B509 (2001) 239 • Model includes: • Temperature at chemical freeze-out • “Life-time” between chemical and • thermal freeze-out • By comparing two particle ratios • (no regeneration) • Lambda1520 • T= 160 MeV  > 4 fm/c • K(892) • T = 160 MeV   > 1.5 fm/c (1520)/ = 0.039  0.015 at 10% most central Au+Au K*/K- = 0.23  0.05 at 0-10% most central Au+Au Christina Markert Hot Quarks, Sardinia, Mai 2006

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