Comment Heim Theory says its mass is 0.51617049 MeV/c (Score 2) 226
http://en.wikipedia.org/wiki/Heim_theory is an alternate model of particle physics that does a pretty good job of predicting the mass of fundamental particles mathematically.
The theory also allows for particle states that don't exist in the Standard Model, including a neutral electron and two extra light neutrinos, and many other extra states.
What's the predicted mass of the neutral electron particle? It's 0.51617049 MeV/c.