Higgs pair production

This page contains the codes for different models of the Higgs pair production at LHC through gluon fusion.

SM

In this model we calculated the Higgs pair production at LO in full theory for a top quark circulating in the loops (exact form factors at LO for the triangle loop and the box). If you want to circulate a bottom quark just change the mass of the top with the one of the bottom in the paramcard.

The output of MG5 in that case can be download in the attachments : SM

BSM : tthh coupling

Here we have implemented a new coupling tthh which has been described in terms of a new parameter c2 times the gghh coupling that we already had in the SM model. You can modify its value in the block bsminputs of the paramcard. So by setting c2 to 0 you will recover the above SM result.

The output of MG5 in that case can be download in the attachments : tthh

BSM : Additional heavy Higgs resonance

Finally in this case we have considered the possibility of having a heavy Higgs H (called hh in the MG files) as an intermediate state (so that we have the additional process p p > hh > h h that is taken into account). For this model in the paramcard you have the freedom of modifying a wide range of parameters :

• the top yukawa coupling (via the parameter cy)
• the SM-Higgs trilinear coupling (ctr)
• the H coupling to the top (cyH)
• the H coupling to 2 SM-Higgs (ctrH)

The parameters cy and ctr are just factors that multiply the SM couplings. The parameters cyH and ctrH are similarly used but for the new heavy Higgs. Finally you can also modify :

• the H mass (MHH)
• the H decay width (WHH)

The default values for all these parameters come from the Two Higgs Doublet Model (2HDM).

The output of MG5 in that case can be download in the attachments : HeavyHiggs

-- Main.!Hespel Benoît - 12 Dec 2013