MadGraph5_aMC@NLO

Yukawa mass difference

Asked by Andrea

Dear all,

I noticed that if I uses the parameter card that is in the official Madgraph Package 5-v1.5.12 and compare the parameters there to the ones I get if I calculate the parameter card with the tool from the Madgraph webpage, the Yukawa mass for the top quark is different.

For the downloaded package it is 1.74300000E+02 which is identical to the kinematic top mass while it is 1.64500000E+02 GeV for the tool from the webpage (while the kinematic mass is 1.74300000E+02). Is there any reason for that difference?

Cheers,
Andrea

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Valentin Hirschi (valentin-hirschi) said : 		#1

Hi Andrea,

I think this is because of the running of the top mass which should be
evaluated at the Higgs mass for the top Yukawa parameter. So you can either
chose to set the pole mass and Yukawa parameter different because of that
(hence resumming some subleading logs) or set them equal to preserve gauge
invariance. The two cards you compared apparently opted for a different
convention.

Cheers,

On Wed, Aug 21, 2013 at 1:01 PM, Andrea <
<email address hidden>> wrote:

> New question #234376 on MadGraph5:
> https://answers.launchpad.net/madgraph5/+question/234376
>
> Dear all,
>
> I noticed that if I uses the parameter card that is in the official
> Madgraph Package 5-v1.5.12 and compare the parameters there to the ones I
> get if I calculate the parameter card with the tool from the Madgraph
> webpage, the Yukawa mass for the top quark is different.
>
> For the downloaded package it is 1.74300000E+02 which is identical to the
> kinematic top mass while it is 1.64500000E+02 GeV for the tool from the
> webpage (while the kinematic mass is 1.74300000E+02). Is there any reason
> for that difference?
>
> Cheers,
> Andrea
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5.
>

--
Valentin

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