Hi all,


 I studied a bit more in detail the problem of the vub reweighting in
the exclusive analyses.

 First, these are the mx plots for the generic MC hybrid and for the
reweighted one

 Gene MC
 http://www.slac.stanford.edu/~daniele/exclvub/ometest3both.eps

 Our rew
 http://www.slac.stanford.edu/~daniele/exclvub/ometestboth.eps

 Blue is non-res and red is resonant.


 Looking at the integral after reweighting we have the following:

 http://www.slac.stanford.edu/~daniele/exclvub/ometestintegrals.eps

 and the region around .7 GeV is very badly reproduced. This imply that we
have to redo the reweighting with a finer binning is we want to use it
also for the exclusive analyses (this does not imply that it will be
possible).


 Then I studied the non-resonant events that survive the cuts. Here
I compare the hybrid MC with the pure non resonant one.


 Rho:
 ---

 hybrid
 http://www.slac.stanford.edu/BFROOT/www/Physics/Analysis/AWG/InclusiveSL/recoilXSL/plotrhotest/mxhadfit0-vubcomp.ps.gz

 nonreso
 http://www.slac.stanford.edu/BFROOT/www/Physics/Analysis/AWG/InclusiveSL/recoilXSL/plotrhotest2/mxhadfit0-vubcomp.ps.gz


 Omega:
 -----

 hybrid
 http://www.slac.stanford.edu/BFROOT/www/Physics/Analysis/AWG/InclusiveSL/recoilXSL/plotomegatest/mxhadfit0-vubcomp.ps.gz

 nonreso
 http://www.slac.stanford.edu/BFROOT/www/Physics/Analysis/AWG/InclusiveSL/recoilXSL/plotomegatest2/mxhadfit0-vubcomp.ps.gz

 (white is signal and blue is vub background)

 Consider that for the hybrid MC none of the vub background events is due
to non-res decays.


 Looking at these plots I see two major points:

 - since the reweighting factor is ~1 below 1.2GeV you can imagine to add
the hybrid and the non-res plots. This implies that the amout of
non-resonant MC is huge after the cuts.

 - the difference between rho and omega is clear. For the rho the non-res
background is "peaking" around the rho mass while for the omega has
basically  the same shape of the hybrid background. Then, once you
switch from the old hybrid to our hybrid, you get a large difference for
rho and negligible difference for omega (as shown in my plots today).


 Then:

 * we have to redo the rewegthing with bins around the rho/omega mass and
   hope that the resulting non-res background will be small

 * BTW, are we sure that such a reweighting (same integral for very low
   masses) makes sense?

 * in SP5 we have the new reweighting, correct? I think that people that
   will do rholnu and omegalnu analyses will be not so happy about it...



 Daniele