Why is a Hydrogen Atom the most stable state? Free Neutron decay?

Question

A free Neutron decays into a hydrogen atom (Proton, Electron, Electron Neutrino) within 15 minutes. That means that a Down Quark transitions to an Up Quark because 2 Down Quarks + 1 Up Quark is an unstable configuration. (Of course, that implies that all the 95+% mass of a Neutron [and Proton], is TRULY made of "virtual particles.")

So, 2xDown, 1xUp is unstable, even though charge is conserved, yet 2xUp, 1xDown is MORE stable, even though charge is ALSO conserved (with the emission of an Electron)!

PLEASE, and I mean this whole-heartedly, WHY? Clearly, some criteria (mass, charge, etc.) has an implied priority, even though Physicists take Herculean efforts to prove such things are "conserved."

Answer 1

It is a law in physics that if a lower energy state exists , and conservation laws allow it the state will end at the lower energy state, the potential energy turning into kinetic, in the case of water flow from a higher to a lower level, and in various allowed by conservation laws particles in the case of a neutron decaying into a proton electron and electron antineutrino.

In elementary particles, the strong force binds quarks into forming hadrons, in a similar way that the electromagnetic binds electrons to a charged nucleus. The proton, the neutron, all the hadrons are bound states of the valence quarks which then decay to a lower energy level.

It is a complicated theory at the research stage still, QCD on the lattice, that can fit the spectrum of hadrons.

Yes , the proton for example is mainly a sea of quark antiquarks and gluons, see this article.