Hi,

I have successfully implemented a model in SARAH with extensions to the Standard Model. I have two Higgs doublets along with a bi-doublet in the scalar sector and consequentially four VEVs. Now the minimisation equations that SARAH writes are alright but when I run MakeSPheno[], it only shows one error message as following:

SPheno::Tadpoles: No solution found for tadpole equations. Given parameters: (mu12,mu22,mu32,mu42)


The mu parameters are the mass squared parameters I require to be solved from the minimisation equations. Is it because Mathematica is unable to solve the equations? Is there a way out? Any comments/suggestions would be great.

Hi,

that's a bit strange because the equations should be linear in the mass squared parameters, so in principle it should be no problem to solve them. However, I wonder that you have four mass squared: I would expect that the bi-doublet just comes with one m^2 term? Thus, what is fourth parameter?

You can also try if works without calling MakeSPheno.

Cheers,
Florian

Hi,

Thanks for your reply. We have two mass-squared terms corresponding to the bi-doublet and its charge-conjugate state (refer to e.g: 1507.01923 (eq. 2.7) ). There is another issue I was meaning to ask you. How exactly should I write the charge-conjugate state? Simply writing conj[] is not the right way I guess.

Hi,

I'm not sure if I understood your question. But you might check http://sarah.hepforge.org/Diphoton_Models.tar.gz where also some left-right models are included which come with bi-doublets. Maybe, that helps.

Cheers,
Florian

Hi,

Sorry to bother you again. Just to be clearer, I have attached a short png file that clearly states my problem. It will be very helpful if you can please look into it. I have terms like Tr[\tilde\phi \dagger\phi] (phi being the bi-doublet) in the Lagrangian which are causing all the trouble. In the existing left-right models I didn't find such terms in the Lagrangian.

Hi,

well, conj[x] is really interpreted as the complex conjugation of the field. However, SARAH uses this information than to contract also the charge indices correctly, i.e. a 2x2 is contracted via \epsilon_ij while 2^* x 2 via a \delta_ij. Thus, you can use conj for both cases and depending on the different terms, the epsilon (=i\tau_2) are set. If the automatic contraction by SARAH is not the one you want to have (there is some ambiguity to form gauge invariant combination) you can set it manually, see also http://stauby.de/sarah_wiki/index.php?t ... ontraction

Cheers
Florian

Hi,

epsTensor does the trick. Thanks a lot. Now it works !!

Great. Have fun with your model!