Name: Paulina Knees Date: 07/16/20-10:45:12 PM Z


Dear author,
I’m calculating the decay width of a massive neutrino decaying to three SM neutrinos through a Z boson. But when I want to calculate the squared amplitude (including fermion spin sum), I get the following error message:

“Error! DiracTrace has encountered a fatal problem and must abort the computation. The problem reads: Trace still
contains chiral projectors.

I realised that the product of the amplitude and its conjugate contains terms with “gamma^$AL($188)” and “gamma^$AL($189)”, and I don’t really know what it is. Besides, the amplitude I get with FeynArts seems to be right.

Thank you very much for your time,
Bests,

Paulina ([pknees_at_HIDDEN-E-MAIL])