Re: statistics

[Frederick Gray <fegray@berkeley.edu>]

Dear Peter,

> First I don't understand the ratio 
>    muSC*(muSC PP) / muSC
> It should be around 0.9 according to my estimate.

What might not be clear is that the "muSC PP" also implies a muSCA veto.
The muSCA rate is currently 20% of the muSC rate, which would account for the
difference between your ~0.9 estimate and the ~0.7 reality.

> Next I assume that you have the muSC+muPC PP in your
> final event count. 

Yes, the "final event count" in the accumulated statistics plot involves all
detectors with essentially the cuts used in Tom's run8 analysis. 

> If we eliminate muPC from the PP
> condition, we would get .65/0.3 ~2 times more 
> good event. Albeit with more beam electron generated
> accidentals. How serious are those?

>From my point of view, the problem is not with the beam accidentals but with 
recovery of pileup protection from any muSC inefficiency, whether it is 
geometric or electronic (read "CAEN").  This inefficiency may not even be 
constant over the run; please recall this plot:
    http://weak0.physics.berkeley.edu/weakint/research/muons/private/tbanks_dir/TeleConf/2005July5/physTPC-noMuSC.gif

> So my first guess would be to multiply the accumulated
> events/day=1.6E8 from your trendplot by 2 to get
> 3.2E8 events per day. 

Yes, we could make assumptions about untested analysis methods and multiply 
by the factor of your choice.  However, the conservative approach would be 
to make run planning decisions based on our only validated pileup protection 
strategy.  We then reserve the right to be pleasantly surprised later
when the offline analysis gives a consistent fit with muSC-only pileup 
protection on the full dataset.

Thanks,

-- Fred

-- Fred Gray / Visiting Postdoctoral Researcher                 --
-- Department of Physics / University of California, Berkeley   --
-- fegray@berkeley.edu / phone 510-642-2438 / fax 510-642-9811  --