Hej Claus, Nice plots! I have (you will be surprised to hear) a few cosmetic suggestions, which I'll give you in person. You say that the fits depend on the reference and the range of the fit, when comparing to UA1 pbar+p. How sensitively? That is, can you supress the suppression (or enhance it dramatically) with other reasonable choices? You claim that the statistics are not good enough to conclude that the slope changes at high pt in the y~2.2 pi minus spectrum. Can you make this more quantitative by doing the fits. While it is clear that the stats are much better in the lower field settings, it is not clear to me that we cannot get a reasonable result from the high-pt. It seems to me that the A426 and A843 match beautifully (at least visually on a 7 decade plot :-) ), and that the A1692 and A843 match pretty well over 2-300MeV/c. The slope of the 1692 and 2268 samples appears quite less than the lower pt. This is either because the acc. map here is wrong (which doesn't seem reasonable to me, since all looks good for the other settings...unless there is a systematic problem with the BFS acceptance correction) , or because the 'real' underlying distribution is, in fact, different (as we might expect). I suggest, then, that you make fits to the settings individually, and see what the slope is. For presentation purposes, you may also want to have larger bins for the higher pt, since the statistics are rather lower there. Finally, have you any idea how much our momentum resolution affects this result? I suppose Pawel knows the momentum resolution better than anyone, so perhaps he can tell us? I find it striking that the central-peripheral ratio is so flat at high rap, though I don't yet know what it means...perhaps just that we need more data? Nice job Claus, thanks for the plots! Ian > -----Original Message----- > From: owner-brahms-l@bnl.gov [mailto:owner-brahms-l@bnl.gov]On Behalf Of > Claus O. E. Jorgensen > Sent: 5. juli 2002 02:31 > To: brahms-l > Subject: High Pt analysis > > > > I've made some preliminary plots for my qm2002 talk. You can find them > here: > > http://www.nbi.dk/~ekman/highpt/highpt.html > > The main physics plots will be > > - (h++h-)/2 pt spectra for 0-5, 5-10, 10-20 and ~40-60% centrality at > eta=0. > > - pt ratio (R) of central (0-10) to semi-peripheral (~40-60). Here I > conlude that we our measurements indicate a suppression of high pt > particles when comparing central to semi-peripheral collisions - this > comparison is of course independent on fit ranges and reference data > taken with another experiment. > > - ratios of spectra to p+pbar reference (ua1) data. These ratios are > dependent on the choice of reference data and fit ranges/methods. > However, suppression of high pt hadrons is observed and it is more > pronounced for the central collisions. > > - ratios of protons to all hadrons as function of pt. Mesonic vs. > baryonic > jets??? Who knows about this stuff? Is my result reasonalbe (I just > pulled out the numbers)? > > - pi- spectrum at y approx 2.2 for 0-15% central. The statistics are > unfortunately not good enough to make qualitative statements on the > slope at high pt. > > - pi- pt ratios of central (0-10) to semi-peripheral (~40-60). The ratio > constant (within the erros). What do we expect at forward rapidities? > > > Comments and suggestions are very welcome... > > Cheers, > > Claus > > > +-------------------------------------------------------------+ > | Claus Jørgensen | > | Cand. Scient. Phone : (+45) 33 32 49 49 | > | Cell : (+45) 27 28 49 49 | > | Niels Bohr Institute, Ta-2, Office : (+45) 35 32 53 07 | > | Blegdamsvej 17, DK-2100, E-mail : ekman@nbi.dk | > | University of Copenhagen Home : www.nbi.dk/~ekman/ | > +-------------------------------------------------------------+ > > >
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