[Comphep-common] comphep question

[Alexander Kryukov]

Dear Oleg!

Unfortunately, the current version of CompHEP does not support such
feature. However we are working on the corresponding extension.

                   Best wishes,               A.Kryukov

On Mon, 2007-05-21 at 23:13 -0500, Oleg Antipin wrote:
> Dear Comphep Collaboration,
> 
> My name is Oleg Antipin and I am a HEP Ph.D. student at Iowa State University, USA. 
> 
> I have a question about comphep.
> 
> I am using version COMPHEP-4.4.3.
> Interaction vertices have the structure ~ [Factor*Lorentz part], where Factor is
> polinomial of model identifiers and constants.
> 
> I was wondering if it's possible to implement effective vertices into comphep?
> Say if vertex is absent at tree-level, at one loop level form-factors for
> effective vertices will be complicated functions of kinematical variables and
> kinematical regimes.
> Is there any way to define such at the Lagrangian level?
> It seems that program doesn't allow for the "Factor" to be function of the
> kinematical variables.
> Maybe it's possible to put them after program constructs the amplitude for the
> process?
> To give a concrete example, I want to define 2 gluons coupling to Higgs at one
> loop level (coupling occurs through the quark loop). Form-factor for this vertex
> will be real or imaginary function of the kinematical variable s=( p_gluon1 +
> p_gluon2 )^2 depending if Sqrt[s] is enough to produce quark pair.
> 
> Is it possible to create such a structures? 
> 
> Sincerely, Oleg Antipin.
> 
> 
-- 
Alexander Kryukov <kryukov at theory.sinp.msu.ru>
SINP MSU