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Argh, ... should we then more focusing on re-weighting the shape of the mX spectrum coming from higher resonances as best as we can rather than re-weighting branching fractions in the first place? Cheers, Heiko On Tue, 3 Oct 2006, Kerstin Tackmann wrote: > > Hi, > > this is a message from the EvtGen HN. It seems that the D** modeling > for the lineshape was not quite correct in SP6 either. So not only > are SP5 and SP6 different in D** modeling, but neither of them > is really correct... and if you look at the plot linked below, you > can see that these changes in the lineshape shift the peak of the > mass distribution (I vaguely remember we wondered about why the peak > was not at the nominal mean mass when we had a look at the D** > modeling quite a while ago, Heiko...). > > This might be one ingredient in our "we don't quite understand > our charm background" puzzle if similar things are true for the > other D**... > > Cheers, > Kerstin > > ---------- Forwarded message ---------- > Date: Tue, 3 Oct 2006 07:53:53 -0700 > From: David Lange <[log in to unmask]> > To: [log in to unmask] > Newsgroups: > http://babar-hn.slac.stanford.edu:5090/HyperNews/get/event_gen.html > Subject: Re: Question on the differences of the generated D_0*0 shape > between SP6 and SP8 MC > > *** Discussion title: Event Generators > Email replies to [log in to unmask] must include: > In-Reply-To: <[log in to unmask]> > Subject: ...change this to be about your reply. > > Hi Liaoyuan > > I guess you mean 'between sp6 and sp8' below. As your plot illustrates > nicely, some factors were missing in sp5/sp6 lineshapes, in this case, > most importantly phase space factors. If you add the appropriate phase > space factors to your BW curve, you should get the sp8 curve. > > david > > Liaoyuan Dong wrote: > > *** Discussion title: Event Generators > > Email replies to [log in to unmask] must include: > > In-Reply-To: <"/event_gen/498"@babar-hn.slac.stanford.edu> > > Subject: ...change this to be about your reply. > > > > Dear EvtGen experts, > > > > I found there are big differences of the generated D_0*0 shape > > between SP6 and SP8 MC. > > > > I got the D_0*0 shape using the mcTruth information, > > The plots for SP6 and SP8 are shown at: > > > > http://www.slac.stanford.edu/~dongly/hn/sp6sp8.ps > > > > The upper plot shows the D_0^*0 shape for SP6 signal MC, > > the lower plot shows the D_0^*0 shape for SP8 signal MC. > > > > The red curves are the fits with the D_0*0 mass and width > > fixed at the input values (Mass = 2308 MeV and width = 276 MeV). > > So the generated D_0*0 shape of SP6 MC is consistent with > > the input values. > > > > Why there are big differences of the generated D_0*0 > > shape between SP5 and SP6 MC ? > > > > Thanks for any help ! > > > > Cheers, > > Liaoyuan > > >