1. Introduction
---------------
All results and input files are available at
http://www.slac.stanford.edu/xorg/hfag/semi/summer04/summer04.shtml
In the following (in no particular order), the updates for summer 2004
with respect to winter conferences 2004 are discussed.
As usual, some of the error breakdowns can be found in
http://www.slac.stanford.edu/xorg/hfag/semi/summer04/summer04.xls
spreadsheet. This is relevant only for the branching fraction B -> X l
nu and |Vub|.
Both Belle and BABAR have shown many new measurements of Vub based on
inclusive semileptonic B decays; all are evaluated based on the shape
function parameters as determined with the BELLE b-> s gamma spectrum.
2. Changes to common parameters
-------------------------------
We use the updated input parameters for mixing and lifetimes. For more
information, please see
http://lepbosc.web.cern.ch/LEPBOSC/combined_results/mar_20b
and
http://lepbosc.web.cern.ch/LEPBOSC/combined_results/mar_20b/changes.txt
Some of the D branching fractions have changed with the publication of
PDG 2004. All new values are consistent with the old values within the
errors.
For f00 = BF(Upsilon(4S)->B0B0) we now take the value computed in
http://www.slac.stanford.edu/xorg/hfag/osc/beijing_2004/index.html
Assuming non-BBbar decays of the Upsilon(4S) to be negligible, the
precision of this averaged quantity is improved considerably compared
to previous versions. This is most obviously reflected in the chi2 of
the average for B0->D*+lnu, both for the branching fraction and |Vcb|.
3. Average of |Vub| from inclusive measurements on Upsilon(4S)
--------------------------------------------------------------
A substantial change has occurred here with the usage of the BELLE
photon spectrum measurement in B -> s gamma decays. This is used for
the determination of the central values and errors of shape function
parameters, used in virtually all |Vub| determinations in inclusive
charmless semileptonic B decays. The new shape function parameters
have substantially smaller errors (x2) than the ones determined by
CLEO and lead to an increase of Vub (because of their central values).
BELLE has a new determination of |Vub| based on events tagged with a
fully reconstructed hadronic decay of a B meson. This analyis is based
on a phasespace selection with mX < 1.7 GeV and Q2 > 8 GeV2. In
addition, it has re-evaluated its previous two measurements.
BABAR has also re-evaluated its mX < 1.55GeV analysis; note that there
is a typo in the conference paper, it has been corrected for the
average (many thanks to Tadao Nozaki for calling our attention to this
point). In addition, BABAR has three new |Vub| determinations: 1)
electron endpoint spectrum p > 2.0 GeV; 2) mX < 1.7GeV and Q2 > 8GeV2;
3) (El,Q2) cuts.
More details of the averaging are provided in the writeup.
4. Average of B0 -> D* l nu
---------------------------
The DELPHI measurement has been published since the last update, and
the BABAR measurement is close to submission.
5. |Vub| from exclusive measurements on Upsilon(4S)
---------------------------------------------------
This is still only a table and not an average. BABAR has updates on
the branching fraction measurements with events measured on the recoil
of a fully reconstructed hadronic B decay (BRECO) and -- for the first
time -- on the recoil of a partially reconstructed B decay.
BELLE has a measurement of B -> pi l nu, differential in Q2, on the
recoil of a semileptonic B decay and extract Vub in the high-Q2 range
where lattice QCD (unquenched, preliminary) formfactor calculations
are availble.
6. |Vcb| and HQE parameters from inclusive measurements
-------------------------------------------------------
Moments of various distributions have been measured by BABAR, BELLE,
CDF, and CLEO.
7. Conclusion
-------------
Your critical comments will be much appreciated. Please send them to