1 Puzzles in strangeness (the heaviest light quark) Rene Bellwied for the strangeness group Wayne State University u,d s c,b 5,10 MeV ~200 MeV ~1500,4500 MeV ~T c ~ thermalized parton

2 What we have learned in Warsaw 1.) the flavor evolution of the yield scaling from pp to AA 2.) the flavor evolution of recombination in R(CP) and v2 3.) the flavor evolution of R(AA) 4.) the flavor evolution of high pt correlations

3 Strangeness yields from pp to AA Production not well modeled by N part (correlation volume) Add Cu+Cu Canonical suppression increases with increasing strangeness  and  are  not flat

4 Flavor dependence of scaling participant scaling for light quark hadrons binary scaling for heavy flavor quark hadrons PHENIX D-mesons (agrees with Haibin’s measurements)

5 s-quarks are formed primordial Scaling according to quark content? u, d – scale with N part s,c,b – scale with N bin p – N part K 0 s – 1/2*N part + 1/2*N bin  – 2/3*N part + 1/3*N bin  – 1/3*N part + 2/3*N bin  – N bin  – N bin D – N bin N part Does strangeness “see” a different correlation volume ? Is a different phase space density required for strangeness production ? Normalized to central data

6 Nuclear Modification Factor R cp 0-5% 40-60% 0-5% 60-80% Y-4  K 0 s √s NN =200 GeV Baryon and meson suppression sets in at the same quark p T. √s NN =200 GeV Strange R CP signals range of recombination model relevance Recombination scaling can be applied to R CP as well as v2

7 Identified Particle R CP strange R CP well behaved all particles have same R CP for p T >~5 GeV: dominance of fragmentation? no flavor dependence in fragmentation region ?

8 Flavor independence of R AA ? u,d dominated c,b dominated no flavor dependence in energy loss ??

9 R AA of Strange Particles Particles with strange quarks scale differently to non-strange Ordering with strangeness content! s-quark K 0 s,  and h - all scale similarly Au+Au p+p 0-5% √s NN =200 GeV

10 Strange enhancement vs. charm suppression ?

11 Quark Scaled R AA of Strange Particles s-quarks scaled with N Bin u&d-quarks scaled with N part  scaled with N part s-quarks scaled with N Bin u&d-quarks scaled with N part  scaled with N Bin Need  on this plot !!  scales like the heavy flavor mesons Analysis focus on 40 Million pp events and year-4 

12 Flavor dependence of 2-particle correlations ● 50% Proton/Anti-Proton ● 95% π ● Λ ● Anti-Λ ● K S 0 ● 50% p/pbar ■ Λ □ Λbar ● 95% п ■ K 0 s N ch /N Trigger p T Trigger Au+Au 0-5% 1.0<p T Associated <2.0 Same side associated yield: -Ridge effect (  correlation) ? -Coalescence effect ? -Fragmentation effect ? Need more year-4 stats and bins

13 Summary Strange particles are unique in the RHIC environment. They apparently carry the primordial information of the produced s-quarks, in particular in the high pt regime of their spectrum. They are much more abundant than heavy flavor particles and thus can be used to extract detailed information on particle production mechanisms at RHIC energies. There is much more to come from strangeness

14 Ongoing analyses and QM presentations Talk: S.SalurSystem size and energy dependence of strangeness production Posters: G. van Buren The Ratio    at RHIC B. Bezverknhy Initial studies of two particle azimuthal correlations using  baryons in collsions at RHIC H. Caines The effects of varying the correlation volume on strangeness M. A. Lamont High momentum strange baryon anomalies in heavy ion collisions at RHIC C. Markert The influence of medium properties on the resonance production in RHIC collision C. M. Mironov STAR measurements of strange hadron R AuAu and M. G. Munhoz Measurements of K 0 and  production in collisions at 62 GeV Au+Au F. Simon Forward lambda production and nuclear stopping power in d+Au collisions at RHIC J. Speltz Energy dependence systematics of strange and multi-strange particle production R. Bellwied Strange particle production mechanism in pp collisions at RHIC Analyses: M.Lamont, A.Timmins: strange baryons J.Speltz, J.Takahashi, M. Munhoz, J.Faivre, M.Estienne: Multistrange baryons C.Markert,R.Witt,S.Salur: resonances G.Van Buren:Sigma0 B.Bezhverkhny,J.Bielcikova, C.Nattrass, L.Gaillard: identified particle correlations H.Caines: scaling F.Simon: forward physics C.Mironov, H. Jiang, L. Barnby,: dA strangeness in dA M.Hainz, R.Witt, C.Mironov, J.Adams, RB: strangeness in pp C.Mironov: kinks S.Kabana, M. Heinz, C.Markert: pentaquarks S.Lapointe, K.Foranzier, J.Takahashi, M.Munhoz, RB:: SVT analysis Papers in GPC: high pt strange baryons, strange resonances Papers close to GPC: strangeness in pp, strange particle correlations, forward Lambdas, 62 GeV strangeness