Name: V. Shtabovenko (email_not_shown)
Date: 07/03/18-03:18:23 PM Z


Hi,

in the vanilla FeynArts this should work out of the box. In the patched
FeynArts, however,
the masses and couplings are renamed to FCGV["XYZ"] to avoid possible
clashes with the
already defined FeynCalc objects:

Options[FAPatch]

So instead of MZ you have FCGV["MZ"] and so on. Using

SetOptions[InitializeModel,
  ModelEdit :> (M$ClassesDescription =
     M$ClassesDescription /. {FCGV["MZ"] -> MZc, FCGV["MW"] -> MWc,
       FCGV["MH"] -> MHc})]
InitializeModel[{SM, UnitarySM},
   GenericModel -> {Lorentz, UnitaryLorentz}];

gives the desired result.

Cheers,
Vladyslav

Am 03.07.2018 um 18:52 schrieb D. Azevedo:
> Hello Vladyslav,
>
> I imagine this is probably something trivial but I am nonetheless struggling in adding widths to the internal propagators generated with FeynArts. In the manual there's a singular part explaining that
>
> SetOptions[InitializeModel, ModelEdit :>
> (M$ClassesDescription = M$ClassesDescription /. MZ -> MZc)]
>
> should suffice, though in my code
>
> SetOptions[InitializeModel,
> ModelEdit :> (M$ClassesDescription =
> M$ClassesDescription /. {MZ -> MZc, MW -> MWc, MH -> MHc})]
> InitializeModel[{SM, UnitarySM},
> GenericModel -> {Lorentz, UnitaryLorentz}];
>
> NoElectronHCoupling =
> ExcludeFieldPoints -> {FieldPoint[0][-F[2, {1}], F[1, {1}], S[3]],
> FieldPoint[0][-F[2, {1}], F[2, {1}], S[1]],
> FieldPoint[0][-F[2, {1}], F[2, {1}], S[2]]}
>
> part = InsertFields[
> CreateTopologies[0,
> 2 -> 3], {F[2, {1}], -F[2, {1}]} -> {F[3, {3}], -F[3, {3}], S[1]},
> Restrictions -> NoElectronHCoupling, InsertionLevel -> {Classes},
> Model -> {SM, UnitarySM},
> GenericModel -> {Lorentz, UnitaryLorentz}];
> Paint[part, PaintLevel -> {Classes}]
>
> The part pertaining the widths makes no change on the amplitudes (leading to no widths at the propagators). What am I doing wrong?
>
> Thank you,
> Duarte
>



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