Hi all,
I've tried to understand what is the error that we want to use in our
theoretical sys study when varying the exclusive BRs.
The first point that needs to be clear is that I'm assuming that all the
various excl B->ulnu BR are related by isospin relations.
So, once evaluated the error, ALL the exclusive contributions can be
varied within the error by the same factor.
The problem now is what error can be quoted.
I've find out the papers were the measurement are discussed (they're
linked in http://www.slac.stanford.edu/~asarti/recoil/sys/theor_sys.html
webpage). Those are two cleo papers.
The last one is marked 16, Jan 2003. All the various measurements are
reviewed. It is clearly said that the only two indipendent measurements
are the B0 -> pi and B0 -> rho one, while all the others are obtained via
isospin correlations.
So I've focused my attention on them.
In the DECAY.DEC we have exactly the same values as those ones quoted in
PDG: so the error quoted in PDG directly applies to our excl. BR
measurement. The only attention must be paid weighting the errors coming
from rho and pi decays. Those two errors are slighlty different (+/- 60
(symm) on pi and +0.6 -0.7 (asymm) for rho.
Should I do the weighted average of those two errors (given that the
values are exactly scaling with our DECAY.DEC value) and come up with an
asymm error or should I use a symm err of ~0.65 (reasonable error for
doing the sys study)?
It might also be said that values quoted in latest CLEO paper are slightly
different from those ones quoted in PDG but they're all quite consistent
within the present errors, so I propose to stick to PDG errors/values...
Let me know any doubt/question.
Cheers,
Alessio
______________________________________________________
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")
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