From: Ian Bearden (bearden@nbi.dk)
Date: Sun Mar 09 2003 - 07:11:57 EST
I also thought that was the suggestion at the collaboration meeting, though I recall less certainty at that time. I thought, when I saw Bjørn's slides that the issue had been resolved (and the ratios looked funny). I am glad that this is cleared up...I guess if we get another AuAu run, we can do this very well using C4 and TOFWII. -Ian On fredag, mar 7, 2003, at 17:45 Europe/Copenhagen, J.H. Lee wrote: > 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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