[Brahms-l] BRAHMS Minutes 04 May 07

Brahms Analysis Meeting 4th May 2007
====================================
Submitted by Michael Murray

Present:
Hongyan,Selemon, Michael, JH, Chelis, Ramiro

Agenda http://indico.cern.ch/conferenceDisplay.py?confId=15773
Ramiro dAu Normalization
Hongyan dAu Analysis.



Action Items:
Ramiro   Look at ZDC calibration before run 7950
          Study vertex correlation between ZDC and track.
          Look at different spectra in different vertex bins
          Will focus efforts now on production 3.

Hongyan: Make dN/dy, RCP and RdAu using full dAu statistics.


Ramiro:d-Au normalization
=========================
Please look at dAu analaysis at
http://www4.rcf.bnl.gov/~bramreco/mainpage.html

He has tried to recover the "group B" runs, ie those with cross talk  
in inelasticity runs.
inelasticity 5 has problems, try to recover with trig 1 or trig 4.
Trig 1 also has a problem since on the right beam-beam counter a good  
number of counters just go off. Therefore he has decided to use ZDC,  
ie trig 4. The ratio of Trig 5 to trig 4 is between 4 and 5.
When he tries to reconstruct this he finds a slope in the pi-/pi+  
ratio between Pt=1 and 2GeV.

He thinks the pi+ spectrum is OK, since most belong to group "c", ie  
the good runs. He then makes pi-/pi+. However between 1 and 2 GeV the  
Pt dependence of pi- seems wrong. Perhaps make a spectrum for each  
vertex bin. Note trig 5 was in the hardware definition of the triggers.

Steve: How can trigger effect shape? Ramero thinks it is in the  
acceptance maps, since they were done with DST production 1. We need  
to use the same data cuts to make the efficiency maps etc.

Steve: What controls the vertex for group "b".
Ramiro: For normalization use ZDC vertex. For acceptance map use  
track vertex not ZDC vertex.

JH: Raw counts of triggers seem OK.
Michael and Chellis asked about the momentum dependence of the vertex  
reconstruction. Ramiro
says width improves with momentum but he does not know about the  
offset. JH, perhaps the problem is in the ZDC vertex. Ramiro notes  
that their is a 2cm offset between the zdc vertex and the track  
vertex which he didn't think was important.

Action Item: Study vertex correlation between ZDC and track.
Look at different spectra in different vertex bins
Will focus efforts now on production 3.




d+Au analysis	Hongyan Yang

Look at her talk on the March 23rd agenda (she had problems loading a  
2nd talk)
http://indico.cern.ch/conferenceDisplay.py?confId=14065
Including all runs available in d+Au prod3

Class I  : 7643-8077; Class II: 8078-8306; Class III: 8307-8632
roughly these correspond to Ramiros classes.
Ramiro       A           B                   C
Calibration check
Exclusive ratios are studied
    R1=(Ninel*sd5(trig5ok)/Nbb*sd1(trig1ok));
    R2=(Ninel*sd5(trig5ok)/Nzdc*sd4(trig4ok));

These ratios depend on vertex since the resolution of the counters is  
different.

R1 is total number of events in a given vertex for trig 5 divided by  
the same number for the beam-beam counter. She studies the difference  
between  track vertex and inelasticity vertex.
She cannot quite remember if she use MRS or FS for track vertex. Note  
ZDC vertex has to be
calibrated for early runs, say 7600 to 8000.

the ratio INEL/BB over Class I & III, should be used to get the ratio  
R1, then R1*sd1*Ntrig1 is the total number of events for normalization

If we use ZDC, then ratio INEL/ZDC in Class III, to obtain a ratio  
R2, then R2*sd4*Ntrig4 is the total number of events for normalization

Note the vertex range used was very wide, +- 30cm.
R1 depends on class.
Class I   ~ 2.0
Class II  ~ 3.5
Class III ~ 1.8 for certain runs (ref ramiro’s ratio vs. runno)

Ramiro feels that the beam-beam ratio is unstable.

For R2, ratio is pretty stable near 4. Of course it has some  
dependence on beam shape.
Action Item: Ramiro will look at ZDC calibration before run 7950

For class 2 she made spectra with R1=2 and R2=4. These seem to be  
consistent.

For her talk of today she mislabeled the pi-spectrum. She will update  
it today tomorrow.

She has produced particle ratios at y=0,1 and 3 as a function of  
centrality. At y=3 she has some problems with pi-/pi+. Please comment  
on the ratios by email.

She is now working on, yield vs rapidity, net-proton dN/dy and Rcp  
and RdAu



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