= Zh production =

This page contains the codes for calculating cross sections or generate event for Zh associated production at LHC through gluon fusion. 

'''Authors :  Benoit Hespel and Eleni Vryonidou'''

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== SM ==

[[Image(ZH_diag.png)]]

We calculated the gluon-gluon fusion contribution to Zh production. This is formally part of the NNLO QCD corrections to ZH production in proton-proton collisions. We generate events using the infinite top mass EFT and then with a dedicated reweighting code we introduce the exact quark mass dependance of the loops. 

This code has been checked against the program vh@nnlo (arxiv:1210.5347 [hep-ph]) and can be downloaded here [attachment:ZH_code.tar.gz ZH_code]

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== 2HDM ==

We calculated the gluon-gluon fusion contribution to Zh_i production (where h_i stand for (h,H,A) with the usual notation: h for the light scalar neutral boson, H for the heavy one and A for the pseudoscalar boson). Like in the SM this is part of the NNLO QCD corrections to Zh_i production in proton-proton collisions. We also used exactly the same technique as before (reweighting of the EFT). 

For pheno studies assistance can be provided to obtain parameter cards for any given 2HDM input that can be used with the following codes.

=== Zh production ===

In the 2HDM there is one additionnal diagram contributing to Zh production with respect to the SM above: the s-channel A contribution.

[[Image(Zh1_diag.png)]]

The code can be downloaded here [attachment:Zh1_code.tar.gz Zh_code]

=== ZH production ===

[[Image(Zh2_diag.png)]]

The code can be downloaded here [attachment:Zh2_code.tar.gz ZH_code]


=== ZA production ===

[[Image(ZA_diag.png)]]

The code can be downloaded here [attachment:ZA_code.tar.gz ZA_code]