Hi Oliver,
thanks for your good comment.
> ^ ^
> Are the two BR results | |
> obtained from the same MC sample?
> If yes, what has caused the shift?
>
As you see in general there is an increase of 20-30% in the error (due to
categories with low statistics). This means that the two results can be
different.
In this particular case
sqrt ( (sigma*1.3)^2 - sigma^2) ) ~ .8 sigma
and 0.0179 - 0.0156 = .0023 = 1.6 * .0014(=sigma(ratio))
So this result is 1.6 sigma off.
Looking in detail
* signal events from the fit w/o categories:
S = 559 +- 44
* signal events from the fit with categories:
S S from truth
32 +- 7 115
31 +- 12 93
220 +- 20 662
190 +- 28 594
15 +- 15 108
21 +- 19 144
total 509 1716
The lack comes from the last two categories and they weight more since
they have a small efficiency. I don't see a fitting problem in these fits
http://www.slac.stanford.edu/~daniele/vub/MCmulti/newMCshapech3ne1fitresults.eps
http://www.slac.stanford.edu/~daniele/vub/MCmulti/newMCshapech3ne2fitresults.eps
BTW I will look into the problem more in detail.
Thanks a lot,
Daniele
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