[Brahms-l] Brahms minutes 16 Oct 09

Minutes of BRAHMS analysis meeting Friday 16 October 2009
=========================================================

Agenda at http://indico.cern.ch/conferenceDisplay.py?confId=71198

09:30 	d/p paper - lambda corrections 	Casper Nygaard (Niels Bohr)

Present: Flemming, Chellis, Ramiro, JH, Michael and Kris

Casper had to take his cat to the vet but he sent an email report.

d/p Casper
==========
Casper has plotted the lambda corrections for all rapidities (and  
both part/anti-part).

The correction  C=1/(1+lambda-part+sigma-part)

.
It takes into account the rapidity dependence of lambda/p from the  
thermal model the efficiency difference in MRS/FS, and incorporates  
the sigma-part into the lambda part by using PHENIX results for sigma/ 
lambda-ratios at y0
(130GeV).

At y=2 the correction is 0.68 at pt=0 and rises to 0.85 at Pt=3GeV.  
This pt dependence is controlled by the difference in slope between  
lambdas and protons. The inverse slopes of the lambdas were estimated  
from Steve's systematic study of <kt> vs Mass at different  
rapidities. To estimate the systematic error on this Casper has also  
calculated the correction assuming T_lambda = Tp. The other extreme  
is to take T_lambda = Tp*M_lambda/Mp. This should result in no pt  
dependence.


There was some discussion of the paper figures. The systematic errors  
on the correction should be incorporated as bands. The error bars  
should be a consistent style, eg not "bars" at the top of the y error  
bars. For the sqrt(s) figure the NA44 and NA49 points may be the  
wrong way around. Flemming suggested solid points for protons, open  
ones for pbars with one shape per energy.


On Other buisness Flemming encouraged people to read Ionuts paper and  
comment on it in the next week.


=============== Minutes submitted by Michael Murray  
======================


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