How to deal with 2HDM for loop

Hi,

> 1. Is there a loop 2HDM or effective 2HDM model? like heft?

Yes such model exists, you should check the FeynRules website.
http://feynrules.irmp.ucl.ac.be/wiki/NLOModels
and check the associate paper to check if this fits your need.

> 2. Why in the loop_MSSM there is no first or second generation quark ? Madgraph think the mass of them are 0 ? Can I change it?
> 3. I want to know which coupling is , for the top top h0 , I generate : t t > h2 and I find in the matrix1.f file ,:
> CALL FFS3_4_0(W(1,1),W(1,2),W(1,3),GC_1783,GC_1783,AMP(1))
> I think this means the coupling is the GC_1783 , can I just change it in the UFO ?

I do not know that model, I assign Hua-Sheng which would be able to answer that part.

> 4. Very strange, when I look at g g > h0 with top loop, I think in the matrix1.f , there should be a coupling GC_1783, but there is no. In fact , I don't find any coupling in the file . So in the loop case, if I want to change the coupling, What should I do?

Those should be in loop_matrix.f
But note that modifying by hand a NLO is very tricky since you need to ensure that all counter-term are changed in a coherent way
(both for UV counter-term and R2 piece).
Modify a LO model should typically be quite safe.

Cheers,

Olivier

> On Mar 7, 2016, at 16:42, Li <email address hidden> wrote:
>
> New question #288031 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/288031
>
> Hi,
> I want to calculate the cross section of a 2 Higgs model with quarks , for example : 1. g g > u u~ h0 via a t channel u/u~ 2. g g > h0 with a quark triangle loop. The h0 is like the 2HDM neutrino higgs
>
> I think MadGraph can do it for me. Then I find in 2HDM model, I can generate the first one and the cross section. But when I want to calculate second one, the madgraph 's 2HDM model can not calculate loop diagram . Then I turn to loop_MSSM and it can produce only the top and bottom quark loop , no first and second generation which I want.
>
> so , there are my questions:
> 1. Is there a loop 2HDM or effective 2HDM model? like heft?
> 2. Why in the loop_MSSM there is no first or second generation quark ? Madgraph think the mass of them are 0 ? Can I change it?
> 3. I want to know which coupling is , for the top top h0 , I generate : t t > h2 and I find in the matrix1.f file ,:
> CALL FFS3_4_0(W(1,1),W(1,2),W(1,3),GC_1783,GC_1783,AMP(1))
> I think this means the coupling is the GC_1783 , can I just change it in the UFO ?
> 4. Very strange, when I look at g g > h0 with top loop, I think in the matrix1.f , there should be a coupling GC_1783, but there is no. In fact , I don't find any coupling in the file . So in the loop case, if I want to change the coupling, What should I do?
>
> ALL I want to do is to calculate the cross section of 1. g g > u u~ h0 via a t channel u/u~ 2. g g > h0 with a quark triangle loop . I want to use 2HDM or MSSM for a prediction. If you have better idea , please tell me.
>
> Best,
> Li
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi,

For the question of loop_MSSM, I would suggest you to not to use this model since this model is not complete for NLO computations. It is only for internal tests. I guess at some point, we should move it to tests. If you want to use NLO model for MSSM, please use

https://feynrules.irmp.ucl.ac.be/wiki/NLOModels for the complete SUSY QCD corrections (click susyqcd_ufo.tar.gz) and the paper http://arxiv.org/abs/1510.00391 is for your reference.

For the coupling, yes, you are right. If you generate t t~ > h0, GC_1783 would be the coupling if you import the model via

> import model loop_MSSM-full

In such case, no merging of different couplings will be used.

Cheers,

Hua-Sheng
On Mar 7, 2016, at 5:57 PM, Olivier Mattelaer <email address hidden> wrote:

> Question #288031 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/288031
>
> Status: Open => Answered
>
> Olivier Mattelaer proposed the following answer:
> Hi,
>
>> 1. Is there a loop 2HDM or effective 2HDM model? like heft?
>
> Yes such model exists, you should check the FeynRules website.
> http://feynrules.irmp.ucl.ac.be/wiki/NLOModels
> and check the associate paper to check if this fits your need.
>
>> 2. Why in the loop_MSSM there is no first or second generation quark ? Madgraph think the mass of them are 0 ? Can I change it?
>> 3. I want to know which coupling is , for the top top h0 , I generate : t t > h2 and I find in the matrix1.f file ,:
>> CALL FFS3_4_0(W(1,1),W(1,2),W(1,3),GC_1783,GC_1783,AMP(1))
>> I think this means the coupling is the GC_1783 , can I just change it in the UFO ?
>
> I do not know that model, I assign Hua-Sheng which would be able to
> answer that part.
>
>
>> 4. Very strange, when I look at g g > h0 with top loop, I think in the matrix1.f , there should be a coupling GC_1783, but there is no. In fact , I don't find any coupling in the file . So in the loop case, if I want to change the coupling, What should I do?
>
> Those should be in loop_matrix.f
> But note that modifying by hand a NLO is very tricky since you need to ensure that all counter-term are changed in a coherent way
> (both for UV counter-term and R2 piece).
> Modify a LO model should typically be quite safe.
>
> Cheers,
>
> Olivier
>
>
>
>> On Mar 7, 2016, at 16:42, Li <email address hidden> wrote:
>>
>> New question #288031 on MadGraph5_aMC@NLO:
>> https://answers.launchpad.net/mg5amcnlo/+question/288031
>>
>> Hi,
>> I want to calculate the cross section of a 2 Higgs model with quarks , for example : 1. g g > u u~ h0 via a t channel u/u~ 2. g g > h0 with a quark triangle loop. The h0 is like the 2HDM neutrino higgs
>>
>> I think MadGraph can do it for me. Then I find in 2HDM model, I can generate the first one and the cross section. But when I want to calculate second one, the madgraph 's 2HDM model can not calculate loop diagram . Then I turn to loop_MSSM and it can produce only the top and bottom quark loop , no first and second generation which I want.
>>
>> so , there are my questions:
>> 1. Is there a loop 2HDM or effective 2HDM model? like heft?
>> 2. Why in the loop_MSSM there is no first or second generation quark ? Madgraph think the mass of them are 0 ? Can I change it?
>> 3. I want to know which coupling is , for the top top h0 , I generate : t t > h2 and I find in the matrix1.f file ,:
>> CALL FFS3_4_0(W(1,1),W(1,2),W(1,3),GC_1783,GC_1783,AMP(1))
>> I think this means the coupling is the GC_1783 , can I just change it in the UFO ?
>> 4. Very strange, when I look at g g > h0 with top loop, I think in the matrix1.f , there should be a coupling GC_1783, but there is no. In fact , I don't find any coupling in the file . So in the loop case, if I want to change the coupling, What should I do?
>>
>> ALL I want to do is to calculate the cross section of 1. g g > u u~ h0 via a t channel u/u~ 2. g g > h0 with a quark triangle loop . I want to use 2HDM or MSSM for a prediction. If you have better idea , please tell me.
>>
>> Best,
>> Li
>>
>> --
>> You received this question notification because you are an answer
>> contact for MadGraph5_aMC@NLO.
>
> --
> You received this question notification because you are assigned to this
> question.

Hi,
  Thanks all! Your explanation and the NLO Models are good!

Best,
Li

Hi,
  Sorry that I find a something confused, when I use the NLO 2hdm model, I generate t t~ > h2 , I find:

      CALL IXXXXX(P(0,1),MDL_MT,NHEL(1),+1*IC(1),W(1,1))
      CALL OXXXXX(P(0,2),MDL_MT,NHEL(2),-1*IC(2),W(1,2))
      CALL SXXXXX(P(0,3),+1*IC(3),W(1,3))
C Amplitude(s) for diagram number 1
      CALL FFS3_4_0(W(1,1),W(1,2),W(1,3),GC_441,GC_336,AMP(1))

  see that there are two couplings, but there should be just only one vertex, which is tth2 vertex?

Best,
Li

Hi,

Looks like this vertex is associated with two lorentz structure and each lorentz structure has it’s own coupling.

Cheers,

Olivier

> On Mar 8, 2016, at 07:32, Li <email address hidden> wrote:
>
> Question #288031 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/288031
>
> Status: Solved => Open
>
> Li is still having a problem:
> Hi,
> Sorry that I find a something confused, when I use the NLO 2hdm model, I generate t t~ > h2 , I find:
>
> CALL IXXXXX(P(0,1),MDL_MT,NHEL(1),+1*IC(1),W(1,1))
> CALL OXXXXX(P(0,2),MDL_MT,NHEL(2),-1*IC(2),W(1,2))
> CALL SXXXXX(P(0,3),+1*IC(3),W(1,3))
> C Amplitude(s) for diagram number 1
> CALL FFS3_4_0(W(1,1),W(1,2),W(1,3),GC_441,GC_336,AMP(1))
>
> see that there are two couplings, but there should be just only one
> vertex, which is tth2 vertex?
>
> Best,
> Li
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier,
  It is wired , but also , thanks a lot !

Best,
Li