Diproton

Diproton (pp)
properties
electric charge	2  e (+3.204 · 10 −19  C )
Spin parity	0 +
Isospin	1 (z component +1)
average lifespan	(not bound)

A diproton is a hypothetical atomic nucleus of helium , consisting of two protons and no neutrons . The strong interaction between the protons has an attractive effect, but at the same time there is also an electrostatic repulsion. The interaction of the two interactions shows that the diproton is not bound and therefore not stable.

If the strength of the strong interaction were only 2 percent stronger, the diproton would be stable. This case is sometimes referred to as a diproton disaster: In this case, life in the universe would not be possible. The fusion within the stars would be brought about by the strong interaction instead of the weak one and would take place about 10 ¹⁸ times faster. Stars would perform nuclear fusion so quickly that no life could develop ( Freeman Dyson ).

The fact that the diproton is not bound can be explained by the Pauli principle together with the fact that the strong interaction is stronger for parallel spins than for antiparallel spins. This is also the reason why the deuteron only exists in the triplet state (S = 1). Since the protons in the hypothetical diproton are identical fermions , they are subject to the Pauli principle, i.e. that is, they cannot have the same quantum numbers . The spins must be aligned antiparallel (singlet). However, this state is not bound due to the spin-dependency of the nuclear force (the nuclear force is stronger with parallel spins of the nucleons). The same consideration applies to the Dineutron .

Diprotons were observed as short-lived states in 2002 in two-proton emission .

Individual evidence

1. ↑ Represented, for example, in PCW Davies , The anthropic principle, Progress in Particle and Nuclear Physics, Volume 10, 1983, p. 8