Slightly positive fermion mass

[charlie]

Hi forum,

May I ask what is the purpose of the tiny positive piece that is added to fermions squared mass in TreeLevelMasses.f90,

Code: Select all

If (Abs(MFv2(i1)).Le.MaxMassNumericalZero) MFv2(i1) = Abs(MFv2(i1))+1.E-10_dp

In my model, this makes my Dirac neutrinos, massless at tree-level, to be Mnu^2=10^-10 GeV^2 instead.

[porod]

HI,

historically, this has been introduced to avoid numerical problems in loop functions where the fermion masses squared enter. However, in the meantime several special cases have been implemented to avoid such numerical problems. I will check if this is indeed still needed.

Best, Werner