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Hi Ric, the dependency as a function of mm2 is striking. I would say that the excess is present only for mm2<0. I added two bins mm2<-0.5 and -0.5<mm2<0. and I produced the data-mc comparison only for the "bad" multiplicity category (nchg=1, nneu>0). Here you find the plot for the B0: -0.5<mm2<0 (nchg=1, nneu>0) http://www.slac.stanford.edu/~daniele/vub/testmm2gt-05B0/comparisonnorm5mxhadfitallcuts.ps.gz mm2<-0.5 (nchg=1, nneu>0) http://www.slac.stanford.edu/~daniele/vub/testmm2lt-05B0/comparisonnorm5mxhadfitallcuts.ps.gz This last plot shows how a peak at 1.5-1.6 GeV is present on data while no event is expected on MC. Since the excess seems to be a reflection of the D peak I investigated the possibility that it could be due to an abundance of low mom kaons on MC and to the cut on kaon momentum (pK>.3 GeV) I tried to remove the cut. No significant improvement was obtained. Daniele On Sat, 18 Jan 2003, Riccardo Faccini wrote: > I have checked for all Bs the agreement between data and MC on Mx in bins > of mm2 and per year. > You can find it in > mm2<0 > http://www.slac.stanford.edu/~rfaccini/phys/vub/deltam/comparison7mxhadfitallcuts-mm2-1.ps > 0<mm2<0.5 > http://www.slac.stanford.edu/~rfaccini/phys/vub/deltam/comparison7mxhadfitallcuts-mm2-2.ps > 0.5<mm2<1.5 > http://www.slac.stanford.edu/~rfaccini/phys/vub/deltam/comparison7mxhadfitallcuts-mm2-3.ps > 1.5<mm2<6 > http://www.slac.stanford.edu/~rfaccini/phys/vub/deltam/comparison7mxhadfitallcuts-mm2-4.ps > mm2>6 > http://www.slac.stanford.edu/~rfaccini/phys/vub/deltam/comparison7mxhadfitallcuts-mm2-5.ps > > As you can see the situation gets worse at low values of mm2, the worst > agreement being for mm2<0. > > As far as different years are concerned > 2000 > http://www.slac.stanford.edu/~rfaccini/phys/vub/deltam/comparison7mxhadfitallcuts-2000.ps > 2001 > http://www.slac.stanford.edu/~rfaccini/phys/vub/deltam/comparison7mxhadfitallcuts-2001.ps > 2002 > http://www.slac.stanford.edu/~rfaccini/phys/vub/deltam/comparison7mxhadfitallcuts-2002.ps > > all the years show an effect, compatibly with the statistics > ciao > ric >