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Vub measurement using recoil of fully reconstructed Bs

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From:
Wolfgang Menges <[log in to unmask]>
Date:
25 Jul 2006 18:02:42 +0200Tue, 25 Jul 2006 18:02:42 +0200
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Hi Kerstin,

	first I have some comments to your numbers, that you are not really 
comparing the correct things, but them I have some other numbers to 
confirm your findings.

So, you can not take the numbers of events in the BSemiExcl data skim to 
calculate any ratios. The contain all data (well, mostly Bs but anyway). 
You have to run them through BbkLumi and use the luminosity or number of 
BB events, which is the same by a constant factor.

And you are neglecting Run3, which might or might not affect the whole 
thing. Anyway, here are the numbers run by run:


generic:

        1235(all/BsemiExcl)  1237(all/BSemiExcl) total      ratio 1235/1237

run1:   24246000  1667945    28762000  1814045   53008000  0.8429
run2:  119356000  8955315   120299826  7443054  239655826  0.9921
run3:   67974000  4742604    61310000  3914416  129284000  1.1087
run4:  332944433 27934200   336130399 24157489  669074832  0.9905

data: lumi       B-counting  AllEvents   BSemiExcl

run1: 19458.963   21181864     268587495   3982175
run2: 60266.741   66441247     866976254  12802202
run3: 31061.051   34076579     447426127   6688118
run4: 99762.620  110107681    1512711646  23104133


sum generic/2/data: (lumi)

run1: 1.362
run2: 1.987
run3: 2.081
run4: 3.353

So, there are two things. There is a minor dependency in the ratio 
charged/neutrals by run period (~15%). There is a strong dependency
in the ratio generic/data by run period.

So, we should weight by different run period. It is possible to 
distinguish between run123 and run4 using the run number. I will see if 
this is also possible for run1, run2 and run3.

How about reweighting between charged and neutral Bs? Could/will be more 
difficult. ;-)

Cheers,

	Wolfgang

Kerstin Tackmann wrote:
> Hi,
> 
> here are some more numbers along these lines...
> 
> I had a closer look at the number of events in the generic MC we are
> using.
> 
> In the reduced ntuples (without any cuts, fits, ...) we have the following
> numbers of entries in the TTree:
> Run1+2  448821
> Run4   1196783
> 
> the ratio of these is 2.667
> 
> looking at Roberto's tcl files, I find these numbers (the numbers of
> events we run over in production):
> Run1-2  19880359
> Run4    52091689
> 
> and the ratio is 2.620.
> 
> This looks to me as if our ratio of generic MC between SP5 and SP6 simply
> does not match the ratio of luminosities in the corresponding runs in
> data. I thought we are supposed to use SP5 and SP6 so that it corresponds
> to the lumi ratios....
> 
> in data I see in the tcl files
> Run1+2  16784377
> Run4    23104133
> 
> and the ratio is 1.377.
> 
> 
> Are we not using all of the generic SP5? Or do we somehow use extra SP6?
> How did this come about? Could someone (Roberto, Wolfgang, ?) please
> clarify this?
> 
> Kerstin
> 
> 
> 
>> The interesting point is that the SP6/SP5 yield is different from
>> the ratio of Run4/Run1+2 luminosities, take e.g. your Vcb 1'bin numbers:
>>
>> SP6/SP5 = 1327.69/482.67 = 2.75
>> Run4/Run1+2 = 100ifb/80ifb = 1.25

-- 
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Wolfgang Menges
Queen Mary, University of London               SLAC, MS 35
Mile End Road                                  2575 Sand Hill Road
London, E1 4NS, UK                             Menlo Park, CA 94025, USA
+44 20 7882 3753                               ++1 650 926 8503
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