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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? Heiko > So I don't think we can trust 100% the numbers used to compute the > correction so far. > > Antonio >