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Hi, Kerstin, do you know more details about this? What is exactly missing and how could we fix it? One possibility would be to have SP6 produced with the correct phase space factors. 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 > > >