Zero cross section for VBF-produced Higgs decay to 4l

Hi,

I'm trying to produce a Higgs via vector boson fusion and then decay to 4 leptons through ZZ*.

I'm also interested in the case where the Higgs decays to 2 photons, for this I use the HEFT model along with the following command:

generate p p > j j h \$\$z w+ w- /p a h HIW = 1 HIG = 0, h > a a

This seems to generate only those Feynman diagrams which produce the Higgs via vector boson fusion and everything works fine. Now, to change this to the 4 lepton case, for electrons I use:

generate p p > j j h \$\$z w+ w- /p a h HIW = 1 HIG = 0, (h > z z, z > e+ e-)

This results in a zero cross section (and also for z > mu+ mu- .) I can't figure out what's causing this problem, any ideas? I haven't modified any cards.

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marco zaro Edit question
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marco zaro
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 Revision history for this message marco zaro (marco-zaro) said on 2015-07-08: #1

Hi,
I think the problem is
(h > z z, z > e+ e-)
if the higgs is light, that forces the two z's to be onshell.
you'd better use

h > e+ e- z
or
h > e+ e- e+ e-

Does this help?

cheers,

Marco

 Revision history for this message William Beggar (yixoyehz) said on 2015-07-08: #2

The h > e+ e- z method worked, thanks!

 Revision history for this message William Beggar (yixoyehz) said on 2015-07-08: #3

Thanks marco zaro, that solved my question.