Specify decay channels using pythia

Asked by Peter Meiring on 2018-10-23

Hi,

In MG5_aMC_v2_6_3_2 I am using the model "loop_sm" to generate dihiggs events like:

./bin/mg5_aMC
import ./models/loop_sm
generate p p > h h [QCD]

This model does not allow for the inclusion of the decay channels of the 2 Higgs particles. If I do:

./bin/mg5_aMC
import ./models/loop_sm
generate p p > h h [QCD], (h > b b~ ), (h > a a)

It returns the following:

Command "generate p p > h h [QCD], (h > b b~ ), (h > a a)" interrupted with error:
InvalidCmd : ML5 cannot yet decay a core process including loop corrections.

Now I should be able to use pythia8 to set the decay channels of the Higgs particles. For example in the pythia8_card I should be able to do something like:

25:onMode=off
25:onIfAny=5 22

This, however, allows also for the possibility of hh > bb~bb~ or hh>aaaa. How can I specify that I only want hh>bbaa?

Cheers!
Peter

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Last query:
2018-10-23
Last reply:
2018-10-23

Hi,

I do not know, you should contact pythia author to know if/how this is possible.

Personally in that case I use madspin in "none" mode (no spin correlation and no offshell effect)

for example with the following script:

generate p p > h h [QCD]
output
launch
madspin=none
edit madspin --after_line=banner import model heft PATH_TO_HEFT_PARAM_CARD --bypass_check
decay h > b b~
decay h > a a --add

the last three lines is to change the madspin_card to

import model heft PATH_TO_HEFT_PARAM_CARD --bypass_check
set spinmode none
decay h > b b~
decay h > a a

Cheers,

Olivier

> On 23 Oct 2018, at 15:57, Peter Meiring <email address hidden> wrote:
>
> New question #675487 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/675487
>
> Hi,
>
> In MG5_aMC_v2_6_3_2 I am using the model "loop_sm" to generate dihiggs events like:
>
> ./bin/mg5_aMC
> import ./models/loop_sm
> generate p p > h h [QCD]
>
> This model does not allow for the inclusion of the decay channels of the 2 Higgs particles. If I do:
>
> ./bin/mg5_aMC
> import ./models/loop_sm
> generate p p > h h [QCD], (h > b b~ ), (h > a a)
>
> It returns the following:
>
> Command "generate p p > h h [QCD], (h > b b~ ), (h > a a)" interrupted with error:
> InvalidCmd : ML5 cannot yet decay a core process including loop corrections.
>
> Now I should be able to use pythia8 to set the decay channels of the Higgs particles. For example in the pythia8_card I should be able to do something like:
>
> 25:onMode=off
> 25:onIfAny=5 22
>
> This, however, allows also for the possibility of hh > bb~bb~ or hh>aaaa. How can I specify that I only want hh>bbaa?
>
> Cheers!
> Peter
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Can you help with this problem?

Provide an answer of your own, or ask Peter Meiring for more information if necessary.

To post a message you must log in.