On Mon, 8 Jan 2001, Michael Murray wrote
> Dear Bjorn,
> thanks very much for your plots, ie
> www.fys.uio.no/~bjornhs/ZDCcorr_MultEff.ps
> It looks like the
> ZDC strong cut is only accepting semicentral and central events.
> What was the data that went into analysis?
As you probably guessed the previous plot was trigger 6 only, as that was
what I had.
> To check the efficency
> of this cut it would be necessary to look at trigger 4 triggers.
> Also to see the efficency could you please plot the ratio of
> (ZDC Strong Cut)/(ZDC weak cut) versus tile multiplicity.
> If this could be done for different triggers it would allow us
> to check the efficency for a wide range of multiplicities.
Now done - I have analysed 50k events from run 2235, which I believe has
no downscaling of triggers 4 and 6 (please correct me if this is wrong!)
The absolute counts are as follows:
Loose cut Strong cut
Tr 4 35054 14417
Tr 6 7056 2487
Another summary plot can be seen at
www.fys.uio.no/~bjornhs/ZDCeff_Run2235_50k.ps
Here, from left to right, are shown tile mult spectra for all events,
trigger 4 and trigger 6 respectively. To get anything from the mult
algorithm you need at least trigger 4, so the two leftmost columns are
identical...
The top row shows the spectra without any ZDC cut, then come the spectra
with a strong cut, a loose cut, and finally the ratio of strong/loose
a.f.o. tile mult for trigger 4 and 6.
Again, I guess a quick conclution is that the strong cut strongly deforms
the MinBias distribution. The efficiency ratios do not seem too different,
only the rise comes slightly later for trigger 6...
Hope this is more or less what you wanted :-)
------------------------------------------------
Bjorn H. Samset
Master-student in Heavy Ion physics
Mob: +47 92 05 19 98 Office: +47 22 85 77 62
Adr: Kri 2A709 Sognsveien 218 0864 Oslo
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