Help with MadSTR

Asked by Rameswar Sahu

Dear Experts,

      I am using the model file SMEFTatNLO with version 3.4.0 of Madgraph. For my work, I need the contribution of four quark operators at the one-loop level, and the authors of the model suggested, and I quote, "The 2. X.X series of MadGraph5_aMC@NLO cannot handle four-quark operators at one-loop". But for my work, I am also considering processes like p p > t w, where at NLO, there is a resonant top quark effect. To take care of those effects, I tried using MadSTR, but it shows the following error "Plugin PLUGIN.MadSTR is not supported by this version of MG5aMC." I checked the earlier queries and came to know that MadSTR at present can only work up to version 2 of Madgraph.

     Is there any alternate way to implement the DR/DS procedures to take care of these resonant effects? Any suggestion is appreciated.


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MadGraph5_aMC@NLO Edit question
marco zaro Edit question
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marco zaro (marco-zaro) said :

Dear Rameswar,
ineed, MadSTR currently works only with MG5_aMC v2 and it is not compatible with v3.
Since you are considering a pretty simple process, you can implement rather easily by hand DR1 just setting to zero the feynman diagrams (AMP(i)) corresponding to resonant top quarks in the real emission processes.
These diagrams appear only in the bbar and gg initiated real emissions.

Please let me know if you need more help

Best wishes,


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Rameswar Sahu (rama7262) said :

Dear Marco,

Thank you for your excellent suggestion. I implemented it, and the program worked smoothly. But p p > t w is not the only process that interests us. Our work also includes other processes like p p > t w h, p p > t w z, etc. These processes involve many diagrams. We will try to generate them using the above method. But if you know of any alternative treatment, it can save us so much time.



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