Implementing massless graviton in Calchep

CalcHEP does not work with spin-2 massless particles.

I do not know how to write Feynman rules for this case and especially
the density matrix for in/out states.

Using g_{mu,nu} for graviton field we have huge number of unphysical
degrees of freedom. We should  control them somehow.

Sent me references, please,  if you have them. I'll try to implement.

Best

    Alexander Pukhov

4/19/22 04:35, Basabendu пишет:
> New question #701409 on CalcHEP:
> https://answers.launchpad.net/calchep/+question/701409
>
> Dear Experts,
>
> I am trying to implement massless spin-2 graviton in calchep. However, it seems I am unable to balance the Lorentz index for graviton vertex. Maybe I am doing something wrong here, but I would like to know if Calchep is capable of handling (massless) spin-2 particles. I am using version 3.8.10.
>
> Thank you.
>

Dear Prof. Pukhov,

Thank you for your reply. I do have the Feynman rules for graviton implementation. Please take a look at the Appendix of the following reference

https://journals.aps.org/prd/abstract/10.1103/PhysRevD.51.2751

I was following this reference to write the vertices. However, I think the problem is with the polarization as you have mentioned.