Hoi Alessio,
very nice talk! Here are just a few nit-picking comments:
p2: "model dep." not due to mb, a parameters, but rather due to shape
function parametrization. The parameters per se are HQET "theory"
parameters, not a model. But the specific form of SF
parametrization in deFazio/Neubert is a model. Which is THE reason
why we want to avoid a dependency on the SF.
p4: I would flip the x-y axes for the "correlation" plot, then it's
the same as other people use, e.g. in the canonical plot of
Bauer/Ligeti (Fig 1 of ph/0107074). I think in general this is
called a "Dalitz" plot, not a "correlation" plot.
p5: I do not think that we need to go as high as 10 GeV2. In fact, IF
we want to put out a result as soon as possible with minimal
changes, I would argue that the q2 cut should be relatively low,
with higher mX cuts than what we have done so far. See e.g. table
I in ph/0107074.
Why 10Gev2?
I have to admit that I have not yet clicked through all the links
in your webpage, I don't know whether you have done this. Ed has
produced scans in the (mX, Q2) plane.
p6: I think that this should be a 2-d scan in (mX,q2), not just a 1-d
scan. You must look at different combinations.
Not only "sys" reduction, but "sys^2 + theo^2". We will not gain
in "sys" probably.
p7: Naive question: Why does the efficiency flatten at mX = 1.8GeV?
Applying a q2 > 10 GeV2 should leave signal rate to higher mX
(both from your plot on page 4 and from ph/0107074).
Again, I think that it should be a 2-d scan of the error not only
vs. q2, but in the full (q2,mX) plane.
p8: By now I think I was confusd and what you call "sys" is actually
"theo"; OK...
p9: I would propose that we very seriously consider switching to the
non-resonant as "default" signal MC. Of course we need to
understand the behavior of the error on the hybrid MC.
p10 I would feel (very) uncomfortable to extract mb from a spectrum
that shows a disagreement between the model and data as shown in
the bottom left two plots.
Before we do that we should be sure that e.g. changing neutrals
selection and tracking has a very small effect on this. There is
work ongoing by Jonathan Coleman which we should look at. I
consider this one of the more important improvements (on a time
scale longer than this summer) for the incl b2u analyses.
p12 Again, I personally would not claim that we can extract mb from
the mX distribution to 80MeV.
p18 "1." I would maybe say that we need to understand the hybrid MC
"For this summer 2." I would say we need to validate the spectra
other than mX given from the fit.
That's all for now.
Cheers,
--U.
