MadGraph5_aMC@NLO

NLO EW corrections with different scheme

Asked by Halley_X

Hi,

I generate a DIS process with pure NLO EW corrections with either alpha(mz) scheme and Gmu scheme. The results of finite terms are very different within two renormalization scheme. As far as I know the difference of the results should be in nnlo, so I'm a little confused.

Sincerely,
Halley

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Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
davide.pagani.85 Edit question
Solved by:
Halley_X
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Olivier Mattelaer (olivier-mattelaer) said : 		#1

How do you DIS at NLO EW within our code?
We do have people starting the implementation of DIS a NLO in QCD within our code and this is not yet working.
(and I know that the code is crashing is someone tries to run it)
So I'm surprised that you do not have a crash in your case.

Can you show me your syntax such that I can investigate why the code is not crashing?

Cheers,

Olivier

Revision history for this message
Halley_X (neuromance) said (last edit ): 		#2

Maybe I didn't make it clear, I use just a initial quark without define a proton in my code cause I only need a subprocess amplitude, which is

set complex_mass_scheme true
import model loop_qcd_qed_sm_Gmu
generate e- u > ve d h [virt=QED]
launch

I get

|| Total(*) Born contribution (GeV^-2):
| Born = 8.9309535208003283e-10
|| Total(*) virtual contribution normalized with born*alpha_S/(2*pi):
| Finite = 2.0107572374825718e+01
| Single pole = -1.8628986150835700e-01
| Double pole = -9.9534614464732427e-02
| (*) The results above sum all starred contributions below

but when I import model loop_qcd_qed_sm which is alpha(mz) scheme, I get

|| Total(*) Born contribution (GeV^-2):
| Born = 9.6810946912626690e-10
|| Total(*) virtual contribution normalized with born*alpha_S/(2*pi):
| Finite = 1.5670263731171270e+01
| Single pole = -1.9136592875754771e-01
| Double pole = -1.0224675560089461e-01
| (*) The results above sum all starred contributions below

The finite terms are different in two schemes. Then I integrate MadLoop loop matrix elements in my own Monte Carlo program the results become more different.

Sincerely,
Halley

Revision history for this message
Halley_X (neuromance) said : 		#3

I misunderstood and my problem solved.