From: J.H. Lee (jhlee@sgs1.hirg.bnl.gov)
Date: Fri Mar 07 2003 - 11:45:42 EST
Hi, Ian, It's due to overestimating pion yields at high pt region where the three sigma cuts start to overlap with Kaons. In other words, it's not from physics. It's from artifacts from overestimated weighting factor. I thought we've answered that at the meeting. If you look at Eun-Joo's presentation slide (p.17), the ratio stops at 2.4 GeV/c not to confuse people with results from the cuts being worked on. Bjorn used numbers from all pt in Eun-Joo's macro. I was working on getting more accurate PID weighting at high-pt side, but somewhat drifted away by other things including the dA run. Anyway, Bjorn, could you please update your slide? JH ----- Original Message ----- From: "Ian Bearden" <bearden@nbi.dk> To: <brahms-l@bnl.gov> Sent: Friday, March 07, 2003 4:42 AM Subject: Re: BNL workshop 6-8 March > Hi all, > I have one comment about Bjxrn's talk (which I also made at the > collaboration meeting, and which I do not think > has been answered satisfactorily ). I do not understand how the p/pi > ratio can fall again above 2 GeV/c. > I am trying to look at the spectra on slide 28, but this doesn't really > help since 1) there are 7 decades plotted and 2) the plot covers to 2.5 > which is where the drop occurs. > So, what happens? Does the proton slope increase radically above 2.5 > or does the pion slope decrease? > Also, why do the errors stay roughly the same above 2GeV? Is there not > a rather large error introduced when we only count > a fraction of the pions, or are the statistics good enough that it > doesn't matter? > Cheers, > Ian > On torsdag, mar 6, 2003, at 18:22 Europe/Copenhagen, Peter H. L. > Christiansen wrote: > > > Hi > > > > I think it would be interesting to see a note on the PID selection > > using > > the "PHENIX" cuts. It is not clear to me how you calculate p/pi at high > > momentum p>2.5 GeV/c, and that the sigma-m2 are meaningful far away > > from > > where they are fitted. The PID picture also looks suspiciously like it > > has > > been renormalized to only contain the selected events... > > > > Could you be a bit more precise about why they don't believe our > > spectra > > at low p_T - do we disagree with the other experiments or have we got > > to little coverage. Do we agree with them or don't we. It would seem > > to me > > that we could at least have some effect at low p from the global > > tracking matching cuts, but is this so? > > > > Nice talk. > > > > Cheers > > Peter > > > > On Thu, 6 Mar 2003, Bjorn H Samset wrote: > > > >> > >> On Wed, 5 Mar 2003, Flemming Videbaek wrote: > >> > >>> Dear Collegue > >>> > >>> Attache is the ref to the agena for the workshop the next comign > >>> days at > >>> BNL. Bjoern Samset is speaking for Brahms tomorrow morning at 9.20 > >>> > >>> See the web ref for the program in general > >>> Flemming > >>> > >> > >> Hello all. The presentation seemed to go well, and judging by the > >> number > >> of questions both during and after the talk people were paying good > >> attention to what we showed. The main questions and comments were > >> about > >> our identified hadron spectra and the mt fit we use - some were > >> sceptical > >> about our ratios because they did not trust our spectra at the low and > >> high ends of the fit range. Also, we got told by several theorists > >> that > >> they KNOW we can do elliptic flow with Si+Tiles, so would we please > >> just > >> go and to the analysis? ;-) > >> > >> The presentation can be found on the BRAHMS presentations page. > >> > >> Ping :-) > >> > >> -- > >> Bjorn H. Samset Phone: 22856465/92051998 > >> PhD student, heavy ion physics Adr: Schouterrassen 6 > >> Inst. of Physics, University of Oslo 0573 Oslo > >> \|/ > >> ----------------------------> -*- <----------------------------- > >> /|\ > >> > >> > > > > -- > > :-) --------------------------- )-: > > Peter H L Christiansen @ NBI > > EMAIL : pchristi@nbi.dk > > OFFICE : Tb1@NBI (353 25269) > > HOME : Frimestervej 22, 1. tv > > PHONE : 35824930/40840492 > > :-D --------------------------- \-: > > > > > > >
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