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Matter 2005 1 System Size and Energy Dependence of Strangeness Production Sevil Salur Yale University for the STAR Collaboration.

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Presentation on theme: "Matter 2005 1 System Size and Energy Dependence of Strangeness Production Sevil Salur Yale University for the STAR Collaboration."— Presentation transcript:

1 sevil.salur@yale.eduQuark Matter 2005 1 System Size and Energy Dependence of Strangeness Production Sevil Salur Yale University for the STAR Collaboration

2 sevil.salur@yale.eduQuark Matter 2005 2 p T spectra and kinetic freeze-out of particles. Investigation of strange particle yields and ratios. Study of resonances (thermal vs chemical freeze-outs ) Comparison of RHIC and SPS yields Strangeness enhancement (Energy dependence & source type) R AA comparison with R CP and R dAu Investigation of strangeness ordering. Is there a scaling in Au+Au production for the strange quarks? N Participants vs N Binary ? Outline

3 sevil.salur@yale.eduQuark Matter 2005 3 200 GeV Au+Au sss  sss  200 GeV Au+Au s  uds  200 GeV Au+Au ss  dss  200 GeV Au+Au The Corrected Strange Particle  Spectra  200 GeV p+p  200 GeV p+p  200 GeV d+Au  200 GeV d+Au  200 GeV d+Au  62 GeV Au+Au  62 GeV Au+Au  62 GeV Au+Au  *(1520) (uds)  *  (uus) QM Posters: R. Bellwied, M.Lamont, C.Markert, M.Munhoz&J.Takahashi, J.Speltz Y-4 Au+Au and Y-5 Cu+Cu is in progress !

4 sevil.salur@yale.eduQuark Matter 2005 4 ,K, p at 200 GeV > 62 GeV T kin at 200 GeV =62 GeV  at 200 GeV = 62 GeV T kin at 200 GeV >62 GeV T kinetic vs Transverse velocity ( ) T kinetic from a Blast-Wave is not same as the Temperature from a Hydro Model. QM Poster: J.Speltz Temperature T kinetic is higher for baryons with higher strange quark content for Blast-wave fits. Spectral shapes are different. Most Central Collisions 0.13 T=100 MeV T=132 MeV

5 sevil.salur@yale.eduQuark Matter 2005 5 STAR Preliminary QM Poster: M.Munhoz&J.Takahashi s-Baryon production is ~constant at mid-rapidity. STAR Preliminary Strange Baryon Production and Collision Energy…  s-Baryon production equals s-Baryon at RHIC Energies!  s-Baryon rises smoothly at mid-rapidity. s-Baryon Resonance follow the same trend. Au+Au Pb+Pb STAR Preliminary

6 sevil.salur@yale.eduQuark Matter 2005 6  /  ratios are approximately independent of the system size at RHIC energies. Strange Particle  Ratios vs System Size    independent of system size at 200 GeV and equal to p+p values at lower energies. QM Poster: C Markert, D. Mishra Re-scattering and regeneration is needed !  t > 0, constant for different centralities! Regeneration σ(K*) > σ(  *)

7 sevil.salur@yale.eduQuark Matter 2005 7  and  yields in AuAu relative to pp rises. System Size Dependence at 200 GeV Correlation volume not well modelled by N part Is the scaling more important than normalization ? Canonical suppression increases with increasing strangeness  and  are  not flat Redlich et al.

8 sevil.salur@yale.eduQuark Matter 2005 8 s-Quarks Have Different Scaling! Scaling according to quark content? u, d – scale with N part – already observed. s – scale with N bin – appears better for strange particles. K 0 s – 1/2*N part + 1/2*N bin p – N part  – 2/3*N part + 1/3*N bin  – 1/3*N part + 2/3*N bin  – N bin  – N bin N part Does strangeness “see” a significant N Bin contribution? Normalized to central data QM Poster: H. Caines  is puzzling!

9 sevil.salur@yale.eduQuark Matter 2005 9 Nuclear Modification Factor R cp 0-5% 40-60% Y-4  K 0 s √s NN =200 GeV Baryons and mesons are different ! QM Poster: M.Lamont 62 GeV R cp shows less suppression. √s NN =62 GeV 0-5% 40-60% Baryon and meson suppression sets in at different p T.

10 sevil.salur@yale.eduQuark Matter 2005 10 Phys. Rev. Lett. 92 (2004) 052302 Au+Au √s NN =200 GeV Au+Au √s NN =62 GeV STAR Preliminary Baryon and meson suppression sets in at same quark p T. 0-5% 40-60% √s NN =200 GeV Nuclear Modification Factor R cp Coalescence vs Fragmentation? 0-5% 40-60% Baryon and meson suppression sets in at different p T. Y-4  K 0 s √s NN =200 GeV

11 sevil.salur@yale.eduQuark Matter 2005 11 s-quark Ordering with strangeness content! Mesons (h + + h -, K 0 s,  ) follow similar trends. Strange baryons don’t show suppression. Rcp  Raa for strange baryons. Canonical suppression in p+p …? s-quarks scaled with N Bin u&d-quarks scaled with N part  scaled with N Part STAR Preliminary Au+Au p+p 0-5% √s NN =200 GeV s-quarks scaled with N Bin u&d-quarks scaled with N part  scaled with N Bin STAR Preliminary Au+Au p+p 0-5% √s NN =200 GeV R AA of Strange Particles STAR Preliminary Au+Au p+p 0-5% √s NN =200 GeV STAR Preliminary Particles with strange quarks scale differently than non-strange!

12 sevil.salur@yale.eduQuark Matter 2005 12 Does entropy drive the strangeness yield? SPS and RHIC data follows same curves… Is there a universal scaling? Enhancements are the same or even bigger at RHIC than at SPS ! Instead of N part  dN ch /dη Correlated to the entropy of the system!

13 sevil.salur@yale.eduQuark Matter 2005 13 Summary and Conclusions  Transverse velocity  T increases with collision energy. T FO  > T FO  from Blast-wave but T FO  = T FO  from Hydro   s-Baryon production equals that of s-Baryon at RHIC energies. Baryon transport is ~ independent of system size at RHIC energies.  Rescattering and regeneration are required to model resonance production. Cross-sections and lifetimes vary (K* vs  *).  t > 0 between chemical and thermal freezeout for all centralities.  R AA different than R CP - canonical suppression is being investigated in R AA and R dAu. Coalescence can explain the meson baryon difference at 62 GeV collisions too.  Particles with s-quarks appear to scale differently than non-s quarks. Maybe s-quarks “see“ a different correlation volume than light quarks?  Yields scale with dN ch /d  for SPS and RHIC (universal scaling?)

14 sevil.salur@yale.eduQuark Matter 2005 14 19 D. Mishra Measurement of  ++ and K ∗ production in d+Au collisions at √s NN = 200 GeV 33 G. Van Buren The Ratio    at RHIC 60 R. Bellwied Strange particle production mechanisms in pp collisions at RHIC 61 B. Bezverkhny Initial studies of two particle azimuthal correlations using  baryons in collisions at RHIC 67 L. Gaillard Identified two-hadron correlations at STAR using ,  and K 0 s with charged hadrons in AuAu at √s NN = 200 GeV 131 H. Caines The effects of varying the correlation volume on strangeness 146 M. A. Lamont High momentum strange baryon anomalies in heavy ion collisions at RHIC 151 C. Markert The influence of medium properties on the resonance production in RHIC collision 152 C. M. Mironov STAR measurements of strange hadron R AuAu and R dAu 155 M. G. Munhoz Measurements of K 0 s and  production in collisions at √s NN = 62 GeV Au+Au 163 F. Simon Forward  production and nuclear stopping power in d+Au collisions at RHIC 164 J. Speltz Energy dependence systematics of strange and multi-strange particle production 167 A. Tang Strangelet search at RHIC Strange Poster Presentations:

15 sevil.salur@yale.eduQuark Matter 2005 15 EXTRAS…

16 sevil.salur@yale.eduQuark Matter 2005 16

17 sevil.salur@yale.eduQuark Matter 2005 17 Nuclear Modification Factor R dAu QM Poster: C. Mironov Resonances follow a similar trend ! Cronin Effect might explain R dAu above 1 Less so for mesons than baryons ! d+Au p+p √s NN =200 GeV


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