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Numerical problem for the SM Wilson coefficient of the process b->c \tau\nu

Posted: 29. Sep 2016, 20:10
by Dris
Dear Florian,
In the Flavorkit convention the SM Wilson coefficient at tree level is given by

C_SM= - g2^2*ZEL(3,3)*ZDL(3,j1)*ZUL(2,j1)/(2*mW^2)
~ g2^2* ZEL(3,3)*ZDL(3,3)*ZUL(2,3)/(2*mW^2)
the inputs are
g2=0.65 , ZEL(3,3)=1 , ZDL(3,3)=0.999 , ZUL(2,3) = 0.042

we should get C_SM=-1.37461*10^-6, but the output is -2.88944926*10^-6.

The inputs of PreSARAH and Flavorkit are attache.

Best.

Re: Numerical problem for the SM Wilson coefficient of the process b->c \tau\nu

Posted: 1. Oct 2016, 15:28
by FStaub
Hi,

here is a beta-version https://flstaub.web.cern.ch/flstaub/SAR ... 2b2.tar.gz with different normalisation.

Cheers,
Florian

Re: Numerical problem for the SM Wilson coefficient of the process b->c \tau\nu

Posted: 3. Oct 2016, 22:59
by Dris
Thanks a lot.

Dris.