In a parallel thread under the headline „Does formation of elementary particles confirm Mach's principle?“ (see reference below) we are meanwhile discussing the internal structure of protons and electrons. Special attention is devoted there to the Compton wavelength λC = h/mc which, in fact, represents the „experimental“ radius rCom of the respective particle. By multiplying with the respective rest mass mrest we obtain the simple relation mrestrCom = h/c which obviously applies to both, the proton (subscript p) and the electron (subscript e). So we can write:
mprp = mere = h/c
The above relation became essential to the development of a semi-classical „triple-gyro“ model of the proton (see reference below). Modeling was inspired by the idea that energy should generally occur in two distinct states of existence, a propagating and a localized one, with the latter being established by rotation. This, in fact, reflects the well known wave-particle duality as also suggested by Planck's constant h on the right hand side of the above relation.
Now we might raise the question whether or not it will make sense to define some elementary quanta of mass and length. Wolfgang Finkelnburg in his textbook „Einführung in die Atomphysik“ (see reference below) already in the 1940s proposed the Compton wavelength of the proton, besides the so called „classical“ electron radius (!), as a candidate for the shortest, i.e., elementary length. In view of mere = h/c, shouldn't we assume me to be a candidate for the smallest, i.e., elementary mass, as recently suggested by Sofia Wechsler in the parallel discussion mentioned above?
https://www.researchgate.net/post/Does_formation_of_elementary_particles_confirm_Machs_principle
Research Proposal Triple-gyro model for deduction of proton radius and magnetic moment
https://books.google.de/books/about/Einf%C3%BChrung_in_die_Atomphysik.html?id=nwQsAAAAIAAJ&redir_esc=y