Why do certain mesons not self-destruct?
12433
How do $\pi^0$ particles exist?
86295
Creation and annihilation operators in the hydrogen atom
34280
Why does the quarks binding energy add mass to nucleons instead of reducing it?
123129
Why can't a particle penetrate an infinite potential barrier?
113599
A proton and antiproton annihilate at rest into pions
61603
Why is the Yang–Mills existence and mass gap problem so fundamental?
104852
Why can't a spin-1 particle decay into two identical spin-0 particles?
37227
Spontaneous pair production?
10413
Why do quarks tend to bond in groups of three?
44311
The Cracks in the Universe: Why are they lethal to some, but not to others?
1330
Fermions, different species and (anti-)commutation rules
29805
Why is quantum entanglement considered to be an active link between particles?
120567
Why is the decay of a neutral rho meson into two neutral pions forbidden?
35409
Massless charged particles
45283
Why don't virtual particles violate conservation of mass/energy?
62506
Why $SU(3)$ and not $U(3)$?
73049
Quantum Zeno effect and unstable particles