How to set aEWM1?

Asked by Gang Li on 2017-11-03

Dear MG5 team,

I am interested in the process

e+ e- > mu+ mu- a

at future e+ e- colliders, say ILC with sqrt{s}=250 GeV.

There are 2->3 subprocess (e+ e- > mu+ mu- a) and also 2->2 & 1->2 subprocess (e+ e- > z a, z > mu+ mu- ).

Now consider that Z boson is replace by Zprime with mass ranging from 10 GeV to 150 GeV, how should I set aEWM1?

Thanks a lot.

Best,
Gang Li

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
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Solved by:
Gang Li
Solved:
2017-11-05
Last query:
2017-11-05
Last reply:
2017-11-03

This question was reopened

Gang Li (ligangpku) said : #2

Sorry, I should explain that

Zprime coupling to leptons = \epsilon \times the SM Z boson coupling to leptons

where \epsilon is some mixing parameter.

Best,
Gang Li

Hi Gang Li,

MG5aMC does not support the running of aEWM1, which is probably your question here (is it)?
In principle since we do the running for the aS, you can trick the model to do such running by slightly modified the
Source/MODEL directory. (but you need to provide the running of aEWM1 via external function obviously)

Cheers,

Olivier

Gang Li (ligangpku) said : #4

Hi Olivier,

Thanks a lot. This helps.

Best,
Gang Li