In addition to this there is also a quantum effect called quantum tunneling [1] which allows for a very tiny probability for particles with insufficient energy

In addition to this there is also a quantum effect called quantum tunneling [1] which allows for a very tiny probability for particles with insufficient energy to fuse upon collision anyway. [1] https://en.wikipedia.org/wiki/Quantum_tunnelling#Nuclear_fusion_in_stars https://en.wikipedia.org/wiki/Quantum_tunnelling#Nuclear_fus...