A question was asked a number of times on this forum, mostly in 2011-2013, of the theoretical reasons for exactly 3 generations of elementary particles. The answers mentioned that certain observed processes could not happen with less than 3 generations, but at that time almost all sources (except this) agreed that the specific reasons for exactly 3 generations were unknown.

My question is if there have been any theoretical developments lately suggesting a theoretical reason fo the number of generations being exactly 3.

The question is about potential recent developments, please do not mark it as a "duplicate" of questions asked years ago.

  • $\begingroup$ A complete answer to this question would be "No". Or rather, theories may exist, but there is no confirmation as of yet for any beyond the SM theory. $\endgroup$ – Omry Oct 12 '17 at 8:06
  • 1
    $\begingroup$ If you have credible reason to believe there are new answers to old questions, the correct way to entice users to post these answers is to offer a bounty with the "Current answers are outdated" reason, not to duplicate the question. $\endgroup$ – ACuriousMind Oct 12 '17 at 8:22
  • $\begingroup$ @ACuriousMind With all due respect, this makes no sense. I have no reason to believe in anything, I am asking, not answering. The earlier question is not a duplicate, as there is a logical difference between only 3 (a limitation) and exactly 3 (a reflection of a fundamental symmetry). This censorship is unreasonable and unnecessary. $\endgroup$ – safesphere Oct 12 '17 at 14:57