In these MIT Lecture notes (section 4.1.2, Page 7(53)) it says:
"We must then choose the odd-parity solution in order to obtain a finite wavefunction at $r= 0$. Thus in 3D, only the odd solutions are possible and we need a minimum potential well depth in order to find a bound state."
Could you explain to me why that's the case? Why are even functions not admissible solutions? Precluding these solutions doesn't make any physical sense, because an even distribution at the center does not seem to break any symmetry of the equation.
Is there a mistake in the lecture? or did I miss something?