Definition of yukawa top coupling

Hi,

Since this might be model dependent, I will give you how I found the information for the SM model, such that you can apply the same method for any model

first i have enter the command
display interactions h t t~
I got the following information
> Interactions 47 : t~ t h has the following property:
> {
> 'id': 62,
> 'particles': [-6,6,25],
> 'color': [1 T(1,0)],
> 'lorentz': ['FFS4'],
> 'couplings': {(0, 0): 'GC_94'},
> 'orders': {'QED': 1},
> 'loop_particles': None,
> 'type': 'base',
> 'perturbation_type': None
> }

Then I printed the value of the coupling via the command
display couplings GC_94
> name : GC_94
> value : -((complex(0,1)*yt)/cmath.sqrt(2))
> order : {'QED': 1}

Then one can look at the parameters via
display parameters
and search for yt
mdl_yt = (mdl_ymt*mdl_sqrt__2)/mdl_vev

looking at ymt, you will see that this is an external parameter (i.e. one of the entry of the param_card)

Cheers,

Olivier

> On 30 Dec 2021, at 14:45, Steven Jeremies <email address hidden> wrote:
>
> New question #700045 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/700045
>
> Dear mg5 Team,
>
> looking for the vlaue of yukawa top coupling I found the Yukawa block
>
> ## INFORMATION FOR YUKAWA
> ###################################
> Block yukawa
> 6 1.730000e+02 # ymt
> 15 1.777000e+00 # ymtau
>
> ###################################
>
> Does this mean the yukawa top coupling is defined via y_t = 0.5*g_w*mt/mW?
> Thanks in advance!
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.