hi Dieter, > > Dear Djamel, > > very interesting data. I had a brief look, a few comments: > > K-/K+ (y=3.13) = 0.822. We just published 0.67. Something wrong > with K- at y=3.13? This is related to what I was saying : the fit range drives everything, since this range is not big (yield under curve around 20 %), the yield extrapolation can introduce this. If I select another pt range as well as another y width, this might change. Not drastically but significantly. I'll make a plot. > > K+/pi+ (y=3.2) = ((17.4+20.8)/2) / 74.6 = 25% > At midrapidity we (and others) have measured about 15%. > Up to now (AGS, SPS) I have only seen ratios that peak at midrapidity or > stay constant. The K/pi ratio has to go down at large (say 4-5) > rapidities, because the K y-spectra is usually narrower than the pi. > Taking your results seriously would mean that the K+/pi+ ratio peaks way > from midrapidity, say at y=3. This would be very interesting, indeed :) > but we need > the rapidity spectra for K and pi in order to check shapes and widths. > > K-/pi- (y=3.2) = ((11.6+17.1)/2) / 78.3 = 18% > This is strange. I cannot imagine any scenario where the k-/pi- > peaks away from midrapidity (14.6% - STAR). see comment above. > > I think that something is fishy with your yields. > Maybe the small pt-acceptance for kaons? Can you add another > field/angle setting that covers lower pt so we get smaller extrapolation > factors (less than a factor 5)? I'll try another setting that I have checked yet (the acceptance correction maps were not produced due to a stupid mistake). > > With best wishes, > Dieter > > PS. concerning K/pi vs pt: since the mt-slopes are almost the same > (200 +-10) you expect a flat ratio, or? > 'f course, it's just that if you take the points plotted on the pt distributions, and make the ratio yourself, you might find a ratio slightly increasing with pt but it's not relevant considering the errors on the slopes. Djam Djamel Ouerdane ------------------------------------------o | Niels Bohr Institute | Home: | | Blegdamsvej 17, DK-2100 Ø | Jagtvej 141 2D, | | Fax: +45 35 32 50 16 | DK-2200 Copenhagen N | | Tel: +45 35 32 52 69 | +45 35 86 19 74 | | http://www.nbi.dk/~ouerdane | | ouerdane@nbi.dk | o---------------------------------------------------------o
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