tau decays

Hello everyone,

My problem is pretty much related with one of my previous questions (#227597).
I am working on tau decays, here is what I do;

import model sm-full
generate p p > ta+ ta-

@14TeV the tau-pair production cross section is 942.4 pb. Then, with the well known
branching ratio of br(ta- > mu- vm~ vt) = %17.41, I like to find leptonic decays of taus
with 942.4*0.1741^2 = 28.56 pb. So as the next step I do;

import model sm-full
generate p p > ta+ ta- ,\
(ta+ > vt~ mu+ vm) ,\
(ta- > vt mu- vm~)

I modify tau width (as Olivier suggested previously) 2.27x10^-12 ---> 2.27x10^-05
and set cut_decays F in run_card. The result is 1.119e-11, (which will be rescaled with 10^14)
and becomes 1119 pb. !!!!!!!

if I use default cuts on decay products then the result is 6.84e-14, and rescaling back with 10^14
becomes 6.84 pb.

I know that photon and Z interferes in s-channel, but why this interference should effect the results?
Why are these results not consistent? what am I missing here? And what would be the best way
to keep track of tau decays?

thanks in advance.

Alper.