 |
 |
Hi, as agreed in our last phone meeting we will have another one tomorrow, Friday, 8:00-9:xx (since we had to drop the regular one last Tuesday.) I will send you the coordinates for the phone conference in time. I'd like to discuss how we can update asap the (old) results on Run1-2 for the CKM WS with respect to 1) New Neubert model 2) Variation of the SF models 3) Updated numbers from Bauer et al. for mX-q^2 In addition, we should discuss the status concerning the code development for a) Kinematic Fitter b) Partial D* reco c) New tag for VirVubFitter? Cheers, Heiko On Mon, 17 Jan 2005, Heiko Lacker wrote: > Hi, > > I try to summarize what we have learnt so far if I got > everything correctly (please correct me in case I > missed something): > > mxHad <-> mxHadfit > ------------------------------------------------------- > BRBR Not a big improvement when using mxHadfit > concerning statistical errors > However, I would guess that this is not > any more the case when also considering > systematics from b->clnu. > > Moments Errors on Moments seem to be significantly > larger when using mxHad instead of mxHadfit > > At least concerning the second topic we would like to use > a kinematic fitter. How well we are really doing using the > VertexTreeFitter is also not known at this stage. > > My personal point-of-view: > In this situation the only reasonable thing to do wrt the > CKM workshop is to produce updated numbers for Run1+Run2 > concerning: > 1) using the new Neubert calculation > 2) mX-q^2 result using updated numbers from Zoltan and Co. > > In addition one might try to add: > 3) One bin-unfolding for mX > 4) Further Tests on the unfolding and calculation of moments. > > Please give me feedback! > > Cheers, > Heiko > > On Mon, 17 Jan 2005, Kerstin Tackmann wrote: > > > > > Hi Daniele, > > > > > > I ran the VirVubFitter jobs on generic MC using the same genMC files for > > > > the generic MC and as data (as we said on Friday). This uses the ichep > > > > ntuples. You can find the VirVubFitter output in the following directory > > > > at SLAC: ~kerstin/scra. > > > > Taking the numbers from the results.dat for the fitted numbers of events > > > > in the first bin (0..1.55GeV) I find > > > > S/N(mxhadfit) = 1.04 > > > > S/N(mxhad) = 0.98 > > > > so the difference is a lot smaller than what Roberto saw on data if I > > > > remember correctly. Maybe someone could check my numbers to make > > > > sure I did not mess it up? > > > > > > your results show that, as far as the BR measurement is concerned, the fit > > > is not useful at all? > > > this is true for the mx analysis with a cut at 1.55 GeV. I am not sure it > > > is the same for a looser cut. If I compare the two ...fitresults.eps > > > files I notice that the "D0/Dc" bin (the second bin in mx) is quite > > > different between mxhad and mxhadfit. This should imply that there is more > > > background for mxhad if you use loose cuts in mx. > > > > Ok, I understand. Would it be the plan to try to go to a higher mX cut or > > would this mean that what we see here might not be the same for mX-q2? > > > > > > Also I computed the moments for the unfolded spectra. Please find the > > > > tables in here: > > > > http://www.slac.stanford.edu:~/public_html/vubfit/moments_data.pdf > > > > The systematics evaluated are the same we had on Friday: > > > > statistical (on spectrum and detector matrix), multiplicity category > > > > reweighting, B->Xclnu BFs, exclusive D BFs, mb and a from Belle, B->Xulnu > > > > BFs (as done for ichep). > > > > > > > > The first four pages have tables for the uncorrected and the bias > > > > corrected moments as obtained on data for mxhad and mxhadfit. Comparing > > > > the uncertainties it looks like we see quite larger uncertainties on some > > > > of the moments using mxhad. This is coming mostly from the systematics > > > > (see the tables where the uncertainties are split up). I tried to figure > > > > out where this comes from. First having a little closer look at the error > > > > bars on the left plot on page 4 of VR011105.pdf from last Friday you can > > > > see that we have larger error bars for mxhad than for mhadfit, so this is > > > > consistent. > > > > > > but do we understand why the error on the subtraction is different? > > > > I think I am not sure what you mean by error on the subtraction. One the > > charm background subtraction? But I think you said on Friday that we would > > expect to have higher uncertainties on the charm subtraction? > > > > Kerstin > > > > >