The main observables of the rare two-proton emission process—half-life, total energy of the decay, as well as energy and angular correlations between the emitted protons—have been measured for ${}^{48}\mathrm{Ni}$ and ${}^{45}\mathrm{Fe}$ in a recent experiment performed at the GANIL/LISE3 facility. The results, together with previous experimental work, are compared for the first time with calculations performed in the recently developed Gamow coupled-channel (GCC) framework and with three-body predictions from the literature. The comparison with the ${}^{48}\mathrm{Ni}$ and the ${}^{45}\mathrm{Fe}$ two-proton angular distributions with the GCC calculations confirms the adopted strength of the proton-proton interaction for both nuclei, and the predominance of emission at small angles. A comparison with three-body model angular distributions indicates the shell closure of the $f_{7/2}$ orbital for ${}^{48}\mathrm{Ni}$ and a substantial occupancy of the $p$ orbital for ${}^{45}\mathrm{Fe}$. Discrepancies between experimental data and theoretical predictions arise when studying the other observables: half-lives, total energy of the decay, and energy correlations, showing the complexity of the description of the two-proton emission process.

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• Lifetimes & widths
• Nuclear decay
• Nuclear forces
• Nuclear many-body theory
• Nuclear structure & decays
• Proton emission
• 39 ≤ A ≤ 58
• Hyperspherical method
• Optical, coupled-channel & distorted wave models