Just to have the links in the mailing list ...

______________________________________________________
Alessio Sarti     Universita' & I.N.F.N. Ferrara
 tel  +39-0532-974328  Ferrara
roma  +39-06-49914338
SLAC +001-650-926-2972

"... e a un Dio 'fatti il culo' non credere mai..."
(F. De Andre')

"He was turning over in his mind an intresting new concept in
Thau-dimensional physics which unified time, space, magnetism, gravity
and, for some reason, broccoli".  (T. Pratchett: "Pyramids")

---------- Forwarded message ----------
Date: Thu, 23 Jan 2003 11:45:30 -0800 (PST)
From: Riccardo Faccini <[log in to unmask]>
To: Urs Langenegger <[log in to unmask]>
Cc: Daniele Del Re <[log in to unmask]>,
     Alessio Sarti <[log in to unmask]>
Subject: Re: mm2_min

Hi Urs,
I would say that you tests show clearly a correlation between low mm2 and
fake events at 1.6 GeV, and this is interesting.
I checked that you reproduce the same results as daniele for the default
scan (mm2>-1000, prmm2>-3) and you actually agree on the neutral Bs,
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2_danb0.datmxCut.eps
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2_danb0.datmxCutdiff.eps
but not on the charged Bs
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2_danbch.datmxCut.eps
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2_danbch.datmxCutdiff.eps
but I am afraid daniele is still using the problematic B+.

As an addition to your information,
in http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/
I produce the scans for the lower cut on mm2 at mx<1.55 from your dat
files (this is why I was looking at them).

B0
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2bnu.txtmnuSqLow.eps
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2bnu.txtmnuSqLowdiff.eps
Bch
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2bch.txtmnuSqLow.eps
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2bch.txtmnuSqLowdiff.eps
All
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2bal.txtmnuSqLow.eps
http://www.slac.stanford.edu/~rfaccini/phys/vub/mm2_min/mm2bal.txtmnuSqLowdiff.eps

I have a few comments on your and these plots:

- I am missing why you say that there is stability on the first table at
mm2=-0.3 for the B0 if at -0.3 the measurement is 144 and at -0.1  is 99
!!!
- I would in general say that cutting at much more than -0.5 does not make
much sense because you fall in the middle of the resolution (same argument we
apply on the high side). From the scans I am sending you  I would say
that B0 show a sort of plateu at -0.5, and that the point at -0.1
is an ecception. I would therefore put out on the table the point at -0.3
(or at 0.5, but the significance is the same).
- I think it should be stressed in your page that the statistical power of
the measurement changes a lot, since the relative error goes from 12% of
the default analysis to the 15% of the final one, although accidentally
(?) the error stays the same [I am trying to find something that could
cause this systematically, but I can't]. This said of course we would
all be happy to loose stat power to cure a systematics.

I will keep looking into the low mm2 events on my prmm2>-3 events and
their correlation with low purity modes.
	ciao
	ric



On Thu, 23 Jan 2003, Urs Langenegger wrote:

>
> Hoi,
>
> I have updated the page with the new fits (including a cut on prmm2).
>
> Cheers,
> --U.
>
>