# generating hh with different model

Dear all,

I continue my last question. In the last question, I learned that "p p > h h [QCD]" is a LO-process.

Now,I wander why we can make " generate p p > h h " run,when we import "model HeavyHisggsTHDM" or "heft".

What makes me confused is that ,if "p p > h h [QCD]" is LO, " generate p p > h h " can also work under the model above ,evenif it is without "[QCD]". I mean ,under these model , "p p > h h " is also a LO ? And ,Is there a default model corresponding to " p p > h h [QCD]"?

Thanks!

--xin

## Question information

- Language:
- English Edit question

- Status:
- Solved

- Assignee:
- No assignee Edit question

- Solved by:
- Brian Wang

- Solved:
- 2018-10-10

- Last query:
- 2018-10-10

- Last reply:
- 2018-10-10

Hi,

I can not comment for HeavyHisggsTHDM since this is not a default model. (And I do not know that one).

For the heft, the model defines a coupling for "h g g" vertex.

This vertex correspond to the full loop contracted to a single point in the infinite top mass limit.

Note that such limit is valid for single higgs production (and for higgs plus jet production if the jet(s) have a quite low transverse energy) but this is not valid for di-higgs production.

Now I know that some people have written the "g g h" vertex with the full top mass loop dependencies.

But I do not know if such model also include the correct "g g h h" vertex which simulates the box contribution.

Now some BSM model also predicts "g g h" vertex at tree-level (some EFT for example) so you have to read the paper associate to the model to know what each model is doing.

Cheers,

Olivier

PS: You might be interested in this paper: arXiv:1401.7340

Note also that the computation of the two-loop computation are now possible (not in our framework) see: arXiv:1608.04798

Brian Wang (brian1243) said : | #2 |

Hi Olivier，

Thanks for your detailed reply ! So patient you are ! I will have a look at these two papers.

Best Regards,

xin