Re: [Brahms-l] qm04- first drafts

Hello,

I hope everyone will be back to work tomorrow :) 

What I found that the yields of charged particles from dAu and pp at
midrapidty are much higher than other experiments (PHENIX, PHOBOS and
STAR). For min-bias of dAu, the yields ~20% systematically higher than
PHENIX published, while our published data is lower than PHENIX especially
in low pt region. For 0-30% central dAu collision the yields I got even
higher than that PHOBOS publilshed spectra from 0-20% central events. The
reason I guess might be due to: scaledown correction and acceptance
correction. I would appreciate you if you could provide me some idea or
suggestion.

For scaledown correction, it is clear that the inel trigger scaledown 
factor is vertex position and centrality dependent from a two-dimensional 
histogram. I think it is quite understandable since the inel trigger 
efficiency has weak centrality and vertex position dependence. Certainly
if ignoring this weak dependence, the yield for central collisions will be
lowered, but I think that not the right thing to do. I would appreciate
if you could show your experience in how to deal with the scale down 
factor correctly or reasonablly.

I still doubt the acceptance map. The map generated from BRAG is very much 
different from map generated from Claus' pure geometrical method (the 
same cut on slats of tofw is applied). And the map from BRAG for B1000 is 
also very much different from that for B1050. The map generated from BRAG 
doesn't match data at all. Then I would think it the current is wrong, I 
mean much lower than 1050 actally, then the acceptance correction might
be larger, then the yield will be lower. 

I would use constructed spectra from PHENIX pi^0 spectra for pp 
collisions+Pythia  simulation as reference spectrum for R_AA of pi at both
mid-rapidity and forward rapidity. 

By the way I have re-studied the RICH efficiency via simulation for 12A427 
with a fiducial cut applied on track intersetion with RICH mid-plane. The RICH 
efficiecy for pion at pt>3GeV/c is ~97% constantly. 

I will update my QM04 draf on the web tomorrow. 

Good night!

Zhongbao


On Sun, 28 Dec 2003, flemming videbaek wrote:

> As per request, we have placed the first versions as has been send to us so far on
> http://www.sdcc.bnl.gov/brahms/private/presentations/2003/QM04/index.html
> 
> Please send comments to presenter, speakers bureau to develop these talks. 
> The goal is to follow the schedule given to the presenters of
> 
> Dec. 22: "rough draft" of talks.  Please send a ppt file to the 
> including figures you know you will show, and preliminary versions of 
> figures you hope to be able to make in time to show.
> 
> Jan 3. Final draft ppt file, together with an outline of what you plan 
> to say
> 
> Jan 7 "final" version of talk, including reasonable suggestions
> 
> Week of Jan 7: Give "final" talk for local group (on Friday 9 the plan is to have
> the two us talks be given at BNL)
> 
> Jan 11: (Sunday of QM) Monday/Tuesday  speakers (I believe this is Ramiro and 
> Michael) give rehearsal talk for  other BRAHMS people at QM.  
> (IGB) will try to organize a location for this as well as the other two talks
> 
> On behalf os the speakers bureau
> Flemming
> 
> 
> ----------------------------------------------------------------
> Flemming Videbaek
> Physics Department
> Brookhaven National Laboratory
> 
> e-mail: videbaek@bnl.gov
> phone: 631-344-4106

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Zhongbao YIN                 Phone:  +47-55-582792 (O)
Address:                             +47-55-276803 (H)
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