1. Introduction
---------------
All results and input files are available at
http://www.slac.stanford.edu/xorg/hfag/semi/summer03-eps/summer03.shtml
In the following (in no particular order), the updates for EPS 2003
with respect to PDG 2003 and the winter conferences 2003 are
discussed.
As usual, most of the error breakdowns can be found in
http://www.slac.stanford.edu/xorg/hfag/semi/summer03-eps/summer03.xls
and
http://www.slac.stanford.edu/xorg/hfag/semi/summer03-eps/summer03.gnumeric
spreadsheets.
2. Changes to common parameters
-------------------------------
We use the input parameters for mixing and lifetimes from the PDG 2003
update.
3. Changes to averages
----------------------
o Inclusive semileptonic branching fraction: New lepton(?) tagged
result from CLEO supercedes the published analysis from
1996. Preliminary error breakdown (does not quite add up to the
published systematic, therefore the "HFAG" systematic error of 0.30
is a bit lower than CLEO's 0.33). The reference for the error
breakdown for this result is M. Artuso, private communication.
The reference for the error breakdown for Belle's BRECO result is
T. Iijima, private communication.
o In the correction for f+/f0 a mistake had occurred in the previous
average: The same relative error as for the BF was used; this is
overestimating the error by a factor of two as |Vcb|*F(1) is the
sqrt of the BF. This bug was detected and verified while working on
the inclusion of the BABAR result into the average (which is not yet
contained in the EPS update). This bug is corrected in this
update. The resulting change in the central value of the average is
small (1/5 of the quoted error). The confidence level changes from
5.6% to 2.9%.
A remark to the plot: The ellipses show the \Delta(\chi^2) = 1
contours. This is noted on the plot. The central values and errors
correspond to the scaled values that go into the average. The plot
is therefore a representation of the (input to the) average. It is
not intended to show the published results.
A discussion within HFAG has started as to whether we shall increase
the errors of the experiments by a similar procedure described in
PDG 2002. No conclusion has been reached, and in the meantime the
chi^2/dof and the CL are stated on the plots, so everybody can form
their own impression.
o The same correction of the error on |Vcb|*G(1) from f+/f0 as above
has been corrected. Virtually no effect here, as it is negligible
compared to the other errors.
o New result from BELLE on charmless semileptonic B decays in the form
of an endpoint analysis. Included in summary plot, but not averaged
(since nothing in b->ulnu is yet averaged).
4. Conclusion
-------------
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