Hi Urs,

just (again) a few thoughts and remarks concerning this topic:

The maple code from Seven does not take into account the
correlation between Lambda_bar and lambda_1 which could be large.
In oder to obtain the correlation you just can take the
famous Lambda_bar vs. lambda_1 plot from CLEO (don't take the one
from DELPHI for obvious reasons :-) and estimate the correlation
from there. Once you have the correlation you can use the code
from Seven as starting base - I did this already for the exclusive
B->sg measurement when they needed Lambda_bar striped down by one
order for the BSG Neubert model. It worked.

Concerning the numbers of the QCD parameters
Lambda_bar and lambda_1 (or Lambda_bar and a in your case)
I strongly suggest to use the measurement from CLEO as input.

If I am not mistaken this numbers where used for the inclusive
Vcb value for ICHEP02.
I do not see any good reason not to use this procedure also
for the Vub measurement. Any other choice of numbers will have
to be justified and might face quite a bit of criticism from the
outside (non-BABAR) physics community.


Oliver

On Fri, 14 Feb 2003, Urs Langenegger wrote:

>
> Hoi,
>
> in general, the reference of choice is El Kahdra and Luke:
> hep-ph/0208114
>
> And now I remember that we discussed this already once before.
>
>   http://babar-hn.slac.stanford.edu:5090/HyperNews/get/ISLDecays/222.html
>
> The only  caveat here is  that I am  not sure whether  the correlation
> between lambda1 and lbar is taken into account. We should check it, of
> course.
>
> You can also get the writeup of the CKM workshop either in hardcopy in
> my office or from your (Italian) friends (PaoloG, AchilleS, MarcoB). I
> am not sure whether it is out already.
>
> Cheers,
> --U.
>
>