The previous post misses the point of the mass formulas. Neither attempts to explain why the masses are what they are, they merely attempt to find a relationship that might be explained by a future theoretical model. An example of this in the past is the Balmer series of emission lines from...
I happened to run across PhysicsForums when I did a Bing search on the tau mass and found a thread concerning the Koide formula and a recent measurement by Belle.
My background is a PhD physicist specializing in high energy experimental physics, most recently with the University of Hawaii. I...
In 2006 I came up with a different relationship among the masses of the electron, muon, and tau, which I updated in 2009. Please see arXiv:physics/0602118 for details, but the bottom line is that my formula predicts a tau mass of 1776.81234 (33) MeV, which differs from the Koide prediction by...