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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 > > >