Heiko Lacker ha scritto:
> Hi,
>
> On Wed, 5 Jul 2006, Antonio Petrella wrote:
>
>> Hi all,
>>
>> today I've run again two fit tests, one with the ratio signal/peaking
>> bkg fixed (only on data, this time) and one without fixing the ratio.
>>
>> Results can be found here:
>>
>> http://www.slac.stanford.edu/~petrella/tmp/scra/Ibutest_fixed/
>> http://www.slac.stanford.edu/~petrella/tmp/scra/Ibutest_SUN/
>>
>> General comments:
>>
>> -comparing the right lower plot (which contains the sum of Bch and B0
>> for data)
>>
>> http://www.slac.stanford.edu/~petrella/tmp/scra/Ibutest_fixed/test_fixeddatachop_all-1.eps
>> http://www.slac.stanford.edu/~petrella/tmp/scra/Ibutest_SUN/test_SUNdatachop_all-1.eps
>>
>> we see that the effect of fixing the ratio is to increase the
>> distribution in the low mx region ( 1.55 < mx < 2.1) and to decrease in
>> the high mx region (mx > 2.8 ).
>>
>> So we looked with more attention to fits performed bin by bin to compute
>> the correction factor and...:
>>
>> - the fit in the high mx region for MC depleted has peaking background
>> consistent with 0
>> http://www.slac.stanford.edu/~petrella/tmp/AWG38/depleted/MCsameEND/MCfit_1D_3.103.40.eps
>>
>> http://www.slac.stanford.edu/~petrella/tmp/AWG38/depleted/MCsameEND/MCfit_1D_3.403.70.eps
>>
>> moreover in the Enriched MC the signal and the peaking components are
>> swapped for 3.1 < mx < 3.4!
> This bin is indeed special in the sense that the fit error on the ratio
> sig/peakBG is much smaller than the ones in the neighbourhood and that
> the ratio has a minimum there. I would think that an average over a larger
> mX range would be more appropriate. The question is how to define these
> larger ranges.
>
>> http://www.slac.stanford.edu/~petrella/tmp/AWG38/enriched/MC/MC_enrich_1D_3.103.40.eps
>>
>>
>> - in the low mx region the increase in the mx distribution is due to the
>> behaviour of the double ratio (sig/peak)_DATA/(sig/peak)_MC, where the
>> numerator and denominator go in the opposite direction i.e.: for MC the
>> ratio is small while for data is high, so the net effect of the double
>> ratio is to give a high correction.
>>
>> But fits on MC present clearly some problems: look at
>>
>> http://www.slac.stanford.edu/~petrella/tmp/AWG38/depleted/MCsameEND/MCfit_1D_1.551.90.eps
>> http://www.slac.stanford.edu/~petrella/tmp/AWG38/depleted/MCsameEND/MCfit_1D_1.902.20.eps
> Do these fits correspond to to the two bins where we have the larger
> correction from the double-ratio?
Yes, they are.
Here are the actual correction factors:
mx bin S/P
0-1.55 3.279662 +- 1.171573
1.55-1.90 9.944666 +- 2.600361
1.90-2.20 6.860380 +- 1.603589
2.20-2.50 1.507182 +- 0.594469
2.50-2.80 0.741645 +- 0.377487
2.80-3.10 0.703099 +- 0.561601
3.10-3.40 0.014759 +- 0.076725
3.40-3.70 0.012368 +- 0.230214
3.70-4.20 1.364814 +- 2.520936
4.20-5.00 3.378136 +- 13.007195
Antonio
>
> Heiko
>
>> So I don't think we can trust 100% the numbers used to compute the
>> correction so far.
>>
>> Antonio
>>
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