MadGraph5_aMC@NLO

Regarding the Direct calculation of Interference term

Asked by ouseph cj

Dear Madgraph Experts,
I am considering p v > p v process mediated with both Z and Zprime,
The total x-section is

\sigma_{tot} = \sigma_{Zp}+\sigma{inter}+\sigma_{SM} -----(1),

Is it possible to compute \sigma_{interference} directly through Madgraph ?
 [the calculated \sigma_{int} from (1) contains lot of numerical instability]

Best
ouseph

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Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

MG5aMC can compute interference term between various coupling order.
So if the Zp is associated to two coupling of type "BSM" and the sm is associated to two coupling of type "QED"
then you can use the following syntax:

generate p v > p v BSM^2==2 QED^2==2

(the ^2 means that the coupling restriction is applied at the diagram square level and not at the amplitude level)

Cheers,

Olivier

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ouseph cj (ouseph444) said : 		#2

Thanks Olivier Mattelaer, that solved my question.