now, compare the results from my own workouts (14.7) in my own draft that ultimately leads to (17.3) i'm happy that i'm not that far off in my answers!
https://foxtrotpaparomeo.wordpress.com/2023/01/11/12012023first-order-calculations-of-the-probability-amplitude-for-higgs-boson-to-electron-positron-decay/
take note that (17.3), which is the absolute square of my probability amplitude, doesn't have a factor 2 because i haven't taken into account yet the other spin states of the fermion and anti-fermion in the decay process and you may refer to (10.5) in the resource material i have shared in the earlier toot and you may also notice that in the cited resource material, the reduced matrix (10.4) and the reduced matrix contained in (14.7) in my draft are the same although i have used different notations/symbols
https://foxtrotpaparomeo.wordpress.com/2023/01/11/12012023first-order-calculations-of-the-probability-amplitude-for-higgs-boson-to-electron-positron-decay/
