MadGraph5_aMC@NLO

SM VBF Diagrams doubts

Asked by Nicolás Vergara

I have been performing a study with vector boson fusion processes. I noticed that a few Feynman diagramas, see ( https://github.com/Switchfools/VBFIm/blob/master/cp.png ), have a vertex with W+ instead of a W- as it would be expected by conservation of electric charge. Nevertheless, the final products from W´s decays are correct. I am wondering if for the W+ on the top vertex there is a time direction assumed and in reality it is a W- as expected. Thanks for your comments.
As additional information, I am using MadGraph version MadGraph5_aMC@NLO, and I generate the process as generate p p > l+ l- j j QCD = 0

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Last query:
Last reply:
Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

T-channel propagator are ambiguous on the notion of particle/anti-particle.
All vertex here conserve electric charge, it just depend of what you consider incoming/outcoming particle. (i.e. do you consider that you emit a W+ or do you consider that you absorbe a W-)

Cheers,

Olivier

> On 6 May 2020, at 18:13, Nicolás Vergara <email address hidden> wrote:
>
> New question #690510 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/690510
>
> I have been performing a study with vector boson fusion processes. I noticed that a few Feynman diagramas, see ( https://github.com/Switchfools/VBFIm/blob/master/cp.png ), have a vertex with W+ instead of a W- as it would be expected by conservation of electric charge. Nevertheless, the final products from W´s decays are correct. I am wondering if for the W+ on the top vertex there is a time direction assumed and in reality it is a W- as expected. Thanks for your comments.
> As additional information, I am using MadGraph version MadGraph5_aMC@NLO, and I generate the process as generate p p > l+ l- j j QCD = 0
>
> --
> 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 Nicolás Vergara for more information if necessary.

To post a message you must log in.