AuAu collisions (Fig. 1) we expect that central collisions of AuAu and CuCu show a similar v$_{2}$/ϵ$_{part}$ despite of the large difference of N$_{part}$ . In peripheral CuCu and AuAu collision v$_{2}$/ϵ$_{part}$ should be very similar for the same N$_{part}$ . In order to compare our model with exper- iment we have to determine ( v$_{2}$/ϵ$_{part}$ ) $^{hydro}$, i.e. v$_{2}$/ϵ$_{part}$ for f$_{core}$ = 1. We take ( v$_{2}$/ϵ$_{part}$ ) hydro as 24%, 19.7% and 12.6% for reactions at √$_{s}$ of 200 AGeV, 62 AGeV and 17.2 AGeV, respectively. In fig.5 we display the ex- perimental results from PHOBOS (full symbols), from STAR (open symbols) and from NA49 (open squares) in comparison with our predictions, presented as lines. We see a quite nice agreement. As in our model, for a given number of N$_{part}$ the experimental values of v$_{2}$/ϵ$_{part}$ for CuCu are higher than those for AuAu. Hydrody- namical calculations predict the opposite. This allows to conclude on the underlying mechanism once the error bars of the present preliminary data are further reduced. The situation becomes much more clear when we divide v$_{2}$/ϵ$_{part}$ by f$_{core}$ . Our model predicts a constant. Fig. 6 presents the PHOBOS data for the 4 different systems, AuAu and CuCu at 200 and 64 AGeV . The experimen- tal v$_{2}$/ ( ϵ$_{part}$f$_{core}$ ) is indeed independent of N$_{part}$ which means that the centrality dependence of v$_{2}$/ ( ϵ$_{part}$ ) agrees with that of f$_{core}$ . This does not exclude, of course, that in hydrodynamical calculations a viscosity can be obtained by fitting the centrality dependence of the ex- perimental data. In our approach we do, however, not need such a fit parameter. It is astonishing that even for the most peripheral reactions, where the number of core particles is of the order of 10 and therefore the assump- tion of a hydrodynamical elliptical flow is questionable, the predictions of core - corona model still hold. In our approach v$_{2}$/ϵ$_{part}$ is a property of the plasma particles and therefore one may expect the same central- ity dependence of v$_{2}$/ϵ$_{part}$ for all hadrons (although we cannot exclude that the hadronization itself creates dif- ferences for different types of hadrons). This is, how- ever, not true. The fraction of particles which come from the core depends, according to eq. 1, on the par- ticle species. For all charged particles and π , for which M$_{core}$ ≈ M$_{corona}$ , this dependence is weak [12] (and there- fore we have divided v$_{2}$ by f$_{core}$ ) but for multi-strange hadrons, for which M$_{core}$ >> M$_{corona}$ , this is an impor- tant effect. We expect does not show a scaling with the number of entrained quarks n$_{q}$ which has been observed in the differential spectra for ( m$_{T}$ − m$_{0}$ ) /n$_{q}$ < 1 GeV , with m$_{T}$ ( m$_{0}$ ) being the transverse (rest) mass. The relative ratio of v i 2 ϵ$_{part}$ between baryons and mesons depend on centrality and on the particle species and is not 3/2 corresponding to the ratio of entrained constituent quarks. However, before firm conclusions can be drawn more data have to Fig.7 shows the centrality dependence of v i 2 $_{ϵ$_{part}$}$( N$_{part}$ ) / v charged hadrons 2 ϵ$_{part}$ ( N$_{part}$ ) for the prelimi- nary p$_{T}$ integrated K$_{0}$, Λ , Ξ data as measured by the STAR collaboration [17]. These data are compared with the model, eq. 4. Model and experiment agree within error bars and the trend of the data is well reproduced. We note that the p$_{T}$ integrated value of v$_{2}$ v i 2 ϵ$_{part}$ ( N$_{part}$ ) (4) = f$_{core}$ · M i core f$_{core}$ · M i core + (1 − f$_{core}$ $^{)}$· M i corona · ( v$_{2}$ $_{ϵ$_{part}$}$) $^{hydro}$. FIG. 5: Top: N part dependence of v 2 /ϵ part for charged hadrons in AuAu and CuCu at 200 AGeV and 62 AGeV as measured by PHOBOS[14] and STAR [15, 17] as well as at 17.2 AGeV [16] as measured by NA49 in comparison with theory. Bottom: Zoom of the region of small N part . 0 50 100 150 200 250 300 350 400 0 5 10 15 20 25 30 35 40 45 0 20 40 60 80 100 120 0 5 10 15 20 25 30 4