[Brahms-l] INEL trigger efficiency in pp

Hello.  Since so many people asked about INEL efficency, I just dig up 
my files.  (I thought these things are checked by someone who are 
writing Ph.d thesis. :)  )  Here is the conclusion I made. 

1.  From the Hijing 1.383, our INEL counter is about 72% efficient. 
(see http://www4.rcf.bnl.gov/~hito/run03/hijing_pp_inel_efficiency.gif )

2.  Now, looking into what HIJING 1.383 really is for pp.  I looked at 
dn/deta from raw hijing output.  At, eta=0, it is  2.2 .  From UA5 ppbar 
results (see  http://pdg.lbl.gov/2002/contents_plots.html  you can find 
a postscrip file there.), it shows 2.2 with the words saying "The number 
per pseudorapidity interval is about 10% higher if the rate is 
normalized excluding singly diffractive events rather than to the total 
inelastic rate." This tells me that Hijing pp produces the total 
inelastic collisions.   (This also means the following.  Since we don't 
trigger on  single diffractive events, what we can measure is 90% 
efficient at most.  Our INEL is 72/90=80 % efficient for non-single 
diffractive events.)


If people need it, I can also dig my old files for dAu.


Hiro

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