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Vub measurement using recoil of fully reconstructed Bs

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From:
Riccardo Faccini <[log in to unmask]>
Date:
16 Apr 2004 09:55:04 -0700 (PDT)Fri, 16 Apr 2004 09:55:04 -0700 (PDT)
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Hi Daniele,
this means that when running on R12 we have to apply the cut.
	ciao
	ric

______________________________________________________
Riccardo Faccini
Universita' "La Sapienza" & I.N.F.N. Roma
tel  +39/06/49914798 Fax.: +39/06/4957697
http://www.slac.stanford.edu/~rfaccini
Univ. La Sapienza. 2,Ple Aldo Moro, I-00185 Roma Dipartimento di Fisica

"I don't understand what you say, but I believe I disagree"

On Fri, 16 Apr 2004, Daniele del Re wrote:

>
> Hi Ric,
>
>   as you know, purity at root code level and purity at Beta
> level did not match in release 10. I fixed that for new skims and new
> tables in beta should be as the ones used in bad 540.
> As a consequence the cut you are talking about should be already in place.
> if you remove sb4 you will take only modes that satisfy cut at page
> 82 of BAD 540.
>
> rate on data went down to 1.6% (from 4%) and to below 7% for gene
> MC.
>
> Urs could you take into account this rates and recompute your numbers as
> far as disk needed?
>
> Daniele
>
> On Fri, 16 Apr 2004, Riccardo Faccini wrote:
>
> > Hi,
> > I guess you are right
> > my next suggestion is to cut on purity from the start, i.e. consider only
> > events with a higher purity of the indivual modes.
> > http://www.slac.stanford.edu/~rfaccini/lost+found/purcut.eps
> > shows the distribution of the purity for generic MC events and the cuts
> > that we apply at analysis level (we require the events to have a purity
> > higher than a given one).
> > It looks like we can save quite some time and space if we request for
> > istance that all events have at least one candidate with a 8% purity.
> >
> > 	opinions?
> > 	ciao
> > 	ric
> >
> > On Fri, 16 Apr 2004, Oliver Buchmueller wrote:
> >
> > >
> > >
> > >
> > > It is certainly worth to test whether or not the normalization to
> > > semileptonic events will work and perhaps even improve the
> > > extraction of the BR(bsg). However, given the fact that there
> > > is at least one thesis a stake I would still vote for a production
> > > without cuts - unless someone can proof that an alternative way will work
> > > as well.
> > >
> > > my two cents ...
> > >
> > > Oliver
> > >
> > >
> > >
> > > On Fri, 16 Apr 2004, Riccardo Faccini wrote:
> > >
> > > > hmmm, I see the problem ( ehem and I was among those who thought
> > > > Fabio's thesis...).
> > > > You can normalize to the number of semileptonic events. In this case you
> > > > will be affected by the systematics on the cut on the lepton, but I think
> > > > it will balance the systmatics on the mes fit which will be reduced.
> > > >
> > > > What do people think?
> > > > 	ciao
> > > > 	ric
> > > >
> > > > ______________________________________________________
> > > > Riccardo Faccini
> > > > Universita' "La Sapienza" & I.N.F.N. Roma
> > > > tel  +39/06/49914798 Fax.: +39/06/4957697
> > > > http://www.slac.stanford.edu/~rfaccini
> > > > Univ. La Sapienza. 2,Ple Aldo Moro, I-00185 Roma Dipartimento di Fisica
> > > >
> > > > "I don't understand what you say, but I believe I disagree"
> > > >
> > > > On Fri, 16 Apr 2004, Henning Ulrik Flaecher wrote:
> > > >
> > > > >
> > > > >
> > > > > Hello,
> > > > >
> > > > > I just noticed that the filtering on leptons and photons above a certain
> > > > > energy cut is (most likely) not an option for the bsg analysis as for the
> > > > > branching fraction measurement we need to normalise to an unbiased B
> > > > > sample and so the full Breco sample.
> > > > > This is how it has been done for Fabio's thesis.
> > > > > Requiring a lepton or photon with a certain energy will most likely bias
> > > > > our normalisation sample, e.g. all B->charged hadron decays would be
> > > > > lost, a fraction of the SL decays etc.
> > > > > The reason why the b->ulv analysis can live with this cut is because they
> > > > > measure a double ratio of branching fractions, so they can normalise to a
> > > > > sample with the same cuts applied.
> > > > > At the moment I can't see how we can get around this but appreciate any
> > > > > ideas!
> > > > >
> > > > > Cheers,
> > > > > Henning
> > > > >
> > > >
> > >
> >
>



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